mlir: fix break/continue inside a try/with#27

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gf712 merged 1 commit into from
Jun 28, 2026
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mlir: fix break/continue inside a try/with #27

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288 changes: 288 additions & 0 deletions integration/tests/break_continue_in_try.py
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# Regression test: `break`/`continue` that leaves a `try`/`except` or `with`
# block inside a loop. These previously produced a `cf.br` from inside the
# still-nested python.try/with region to a block in the enclosing loop region
# (an invalid cross-region branch), which sent MLIR's region DCE into unbounded
# recursion and crashed the compiler. os.py's removedirs()/_walk() hit this,
# so `import os` segfaulted.

# break out of an except handler (while) -- the removedirs() shape.
def break_in_except_while(items):
out = []
i = 0
while i < 5:
try:
out.append(items[i])
except IndexError:
break
i += 1
return out

assert break_in_except_while([10, 20]) == [10, 20], break_in_except_while([10, 20])

# continue out of an except handler (for).
def continue_in_except_for(items):
out = []
for x in items:
try:
if x == 0:
raise ValueError("zero")
out.append(x)
except ValueError:
continue
return out

assert continue_in_except_for([1, 0, 2, 0, 5]) == [1, 2, 5], continue_in_except_for([1, 0, 2, 0, 5])

# break from the try body itself (not from a handler).
def break_in_try_body():
out = []
i = 0
while i < 10:
try:
out.append(i)
if i == 3:
break
except Exception:
out.append(-1)
i += 1
return out

assert break_in_try_body() == [0, 1, 2, 3], break_in_try_body()

# break/continue out of a `with` must still run __exit__.
class CM:
def __init__(self, log):
self._log = log
def __enter__(self):
self._log.append("enter")
return self
def __exit__(self, *a):
self._log.append("exit")
return False

def break_out_of_with():
log = []
i = 0
while i < 3:
with CM(log):
if i == 1:
break
i += 1
return log

assert break_out_of_with() == ["enter", "exit", "enter", "exit"], break_out_of_with()

def continue_out_of_with():
log = []
for i in range(3):
with CM(log):
if i == 1:
continue
log.append(("after", i))
return log

assert continue_out_of_with() == [
"enter", "exit", ("after", 0),
"enter", "exit",
"enter", "exit", ("after", 2),
], continue_out_of_with()

# nested try/except with break in the inner handler -- the _walk() shape.
def nested_try_break(values):
out = []
it = iter(values)
while True:
try:
try:
v = next(it)
except StopIteration:
break
except RuntimeError:
out.append("runtime")
continue
out.append(v)
return out

assert nested_try_break([1, 2, 3]) == [1, 2, 3], nested_try_break([1, 2, 3])

# break/continue out of a try must still run its finally first.
def break_in_except_with_finally():
out = []
i = 0
while i < 5:
try:
out.append(("body", i))
raise ValueError
except ValueError:
out.append(("except", i))
break
finally:
out.append(("finally", i))
i += 1
return out

assert break_in_except_with_finally() == [
("body", 0), ("except", 0), ("finally", 0),
], break_in_except_with_finally()

def continue_with_finally():
out = []
for i in range(3):
try:
if i == 1:
raise ValueError
out.append(("ok", i))
except ValueError:
continue
finally:
out.append(("fin", i))
return out

assert continue_with_finally() == [
("ok", 0), ("fin", 0), ("fin", 1), ("ok", 2), ("fin", 2),
], continue_with_finally()

# both break and continue, each unwinding the same finally.
def break_and_continue_with_finally():
out = []
for i in range(6):
try:
if i == 1:
continue
if i == 4:
break
out.append(("ok", i))
finally:
out.append(("fin", i))
return out

assert break_and_continue_with_finally() == [
("ok", 0), ("fin", 0),
("fin", 1),
("ok", 2), ("fin", 2),
("ok", 3), ("fin", 3),
("fin", 4),
], break_and_continue_with_finally()

# break from the try body (no exception raised) still runs finally.
def break_in_body_with_finally():
out = []
i = 0
while i < 5:
try:
out.append(("body", i))
if i == 2:
break
finally:
out.append(("fin", i))
i += 1
return out

assert break_in_body_with_finally() == [
("body", 0), ("fin", 0),
("body", 1), ("fin", 1),
("body", 2), ("fin", 2),
], break_in_body_with_finally()

# break through *nested* try/finally runs every finally, innermost first.
def break_through_nested_finally():
out = []
i = 0
while i < 4:
try:
try:
out.append(("body", i))
if i == 1:
break
finally:
out.append(("inner-fin", i))
finally:
out.append(("outer-fin", i))
i += 1
return out

assert break_through_nested_finally() == [
("body", 0), ("inner-fin", 0), ("outer-fin", 0),
("body", 1), ("inner-fin", 1), ("outer-fin", 1),
], break_through_nested_finally()

# break written *inside* a finally exits the loop.
def break_inside_finally():
out = []
for i in range(4):
try:
out.append(("body", i))
finally:
out.append(("fin", i))
if i == 1:
break
return out

assert break_inside_finally() == [
("body", 0), ("fin", 0), ("body", 1), ("fin", 1),
], break_inside_finally()

# a break inside a finally swallows an exception that is in flight -- even one
# raised by a called function.
def boom():
raise RuntimeError("from callee")

def break_inside_finally_swallows_exception():
out = []
for i in range(4):
try:
out.append(("body", i))
if i == 1:
boom()
finally:
out.append(("fin", i))
if i == 1:
break
return out

assert break_inside_finally_swallows_exception() == [
("body", 0), ("fin", 0), ("body", 1), ("fin", 1),
], break_inside_finally_swallows_exception()

# a continue inside a finally overrides a break in the try body.
def finally_continue_overrides_break():
out = []
for i in range(4):
try:
out.append(("body", i))
if i == 1:
break
finally:
out.append(("fin", i))
if i == 1:
continue
return out

assert finally_continue_overrides_break() == [
("body", 0), ("fin", 0),
("body", 1), ("fin", 1),
("body", 2), ("fin", 2),
("body", 3), ("fin", 3),
], finally_continue_overrides_break()

# a break inside an inner finally still runs the enclosing finally.
def break_inside_inner_finally():
out = []
for i in range(3):
try:
try:
out.append(("inner-body", i))
finally:
out.append(("inner-fin", i))
if i == 1:
break
finally:
out.append(("outer-fin", i))
return out

assert break_inside_inner_finally() == [
("inner-body", 0), ("inner-fin", 0), ("outer-fin", 0),
("inner-body", 1), ("inner-fin", 1), ("outer-fin", 1),
], break_inside_inner_finally()

print("break_continue_in_try: ok")
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})();
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var __re = new RegExp('^' + "github\\.com" + '

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mlir: fix break/continue inside a try/with#27

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 Merged

gf712
merged 1 commit into

from

Jun 28, 2026
 Merged


mlir: fix break/continue inside a try/with
#27
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288 changes: 288 additions & 0 deletions
integration/tests/break_continue_in_try.py

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,288 @@
# Regression test: `break`/`continue` that leaves a `try`/`except` or `with`
# block inside a loop. These previously produced a `cf.br` from inside the
# still-nested python.try/with region to a block in the enclosing loop region
# (an invalid cross-region branch), which sent MLIR's region DCE into unbounded
# recursion and crashed the compiler. os.py's removedirs()/_walk() hit this,
# so `import os` segfaulted.

# break out of an except handler (while) -- the removedirs() shape.
def break_in_except_while(items):
 out = []
 i = 0
 while i < 5:
 try:
 out.append(items[i])
 except IndexError:
 break
 i += 1
 return out

assert break_in_except_while([10, 20]) == [10, 20], break_in_except_while([10, 20])

# continue out of an except handler (for).
def continue_in_except_for(items):
 out = []
 for x in items:
 try:
 if x == 0:
 raise ValueError("zero")
 out.append(x)
 except ValueError:
 continue
 return out

assert continue_in_except_for([1, 0, 2, 0, 5]) == [1, 2, 5], continue_in_except_for([1, 0, 2, 0, 5])

# break from the try body itself (not from a handler).
def break_in_try_body():
 out = []
 i = 0
 while i < 10:
 try:
 out.append(i)
 if i == 3:
 break
 except Exception:
 out.append(-1)
 i += 1
 return out

assert break_in_try_body() == [0, 1, 2, 3], break_in_try_body()

# break/continue out of a `with` must still run __exit__.
class CM:
 def __init__(self, log):
 self._log = log
 def __enter__(self):
 self._log.append("enter")
 return self
 def __exit__(self, *a):
 self._log.append("exit")
 return False

def break_out_of_with():
 log = []
 i = 0
 while i < 3:
 with CM(log):
 if i == 1:
 break
 i += 1
 return log

assert break_out_of_with() == ["enter", "exit", "enter", "exit"], break_out_of_with()

def continue_out_of_with():
 log = []
 for i in range(3):
 with CM(log):
 if i == 1:
 continue
 log.append(("after", i))
 return log

assert continue_out_of_with() == [
 "enter", "exit", ("after", 0),
 "enter", "exit",
 "enter", "exit", ("after", 2),
], continue_out_of_with()

# nested try/except with break in the inner handler -- the _walk() shape.
def nested_try_break(values):
 out = []
 it = iter(values)
 while True:
 try:
 try:
 v = next(it)
 except StopIteration:
 break
 except RuntimeError:
 out.append("runtime")
 continue
 out.append(v)
 return out

assert nested_try_break([1, 2, 3]) == [1, 2, 3], nested_try_break([1, 2, 3])

# break/continue out of a try must still run its finally first.
def break_in_except_with_finally():
 out = []
 i = 0
 while i < 5:
 try:
 out.append(("body", i))
 raise ValueError
 except ValueError:
 out.append(("except", i))
 break
 finally:
 out.append(("finally", i))
 i += 1
 return out

assert break_in_except_with_finally() == [
 ("body", 0), ("except", 0), ("finally", 0),
], break_in_except_with_finally()

def continue_with_finally():
 out = []
 for i in range(3):
 try:
 if i == 1:
 raise ValueError
 out.append(("ok", i))
 except ValueError:
 continue
 finally:
 out.append(("fin", i))
 return out

assert continue_with_finally() == [
 ("ok", 0), ("fin", 0), ("fin", 1), ("ok", 2), ("fin", 2),
], continue_with_finally()

# both break and continue, each unwinding the same finally.
def break_and_continue_with_finally():
 out = []
 for i in range(6):
 try:
 if i == 1:
 continue
 if i == 4:
 break
 out.append(("ok", i))
 finally:
 out.append(("fin", i))
 return out

assert break_and_continue_with_finally() == [
 ("ok", 0), ("fin", 0),
 ("fin", 1),
 ("ok", 2), ("fin", 2),
 ("ok", 3), ("fin", 3),
 ("fin", 4),
], break_and_continue_with_finally()

# break from the try body (no exception raised) still runs finally.
def break_in_body_with_finally():
 out = []
 i = 0
 while i < 5:
 try:
 out.append(("body", i))
 if i == 2:
 break
 finally:
 out.append(("fin", i))
 i += 1
 return out

assert break_in_body_with_finally() == [
 ("body", 0), ("fin", 0),
 ("body", 1), ("fin", 1),
 ("body", 2), ("fin", 2),
], break_in_body_with_finally()

# break through *nested* try/finally runs every finally, innermost first.
def break_through_nested_finally():
 out = []
 i = 0
 while i < 4:
 try:
 try:
 out.append(("body", i))
 if i == 1:
 break
 finally:
 out.append(("inner-fin", i))
 finally:
 out.append(("outer-fin", i))
 i += 1
 return out

assert break_through_nested_finally() == [
 ("body", 0), ("inner-fin", 0), ("outer-fin", 0),
 ("body", 1), ("inner-fin", 1), ("outer-fin", 1),
], break_through_nested_finally()

# break written *inside* a finally exits the loop.
def break_inside_finally():
 out = []
 for i in range(4):
 try:
 out.append(("body", i))
 finally:
 out.append(("fin", i))
 if i == 1:
 break
 return out

assert break_inside_finally() == [
 ("body", 0), ("fin", 0), ("body", 1), ("fin", 1),
], break_inside_finally()

# a break inside a finally swallows an exception that is in flight -- even one
# raised by a called function.
def boom():
 raise RuntimeError("from callee")

def break_inside_finally_swallows_exception():
 out = []
 for i in range(4):
 try:
 out.append(("body", i))
 if i == 1:
 boom()
 finally:
 out.append(("fin", i))
 if i == 1:
 break
 return out

assert break_inside_finally_swallows_exception() == [
 ("body", 0), ("fin", 0), ("body", 1), ("fin", 1),
], break_inside_finally_swallows_exception()

# a continue inside a finally overrides a break in the try body.
def finally_continue_overrides_break():
 out = []
 for i in range(4):
 try:
 out.append(("body", i))
 if i == 1:
 break
 finally:
 out.append(("fin", i))
 if i == 1:
 continue
 return out

assert finally_continue_overrides_break() == [
 ("body", 0), ("fin", 0),
 ("body", 1), ("fin", 1),
 ("body", 2), ("fin", 2),
 ("body", 3), ("fin", 3),
], finally_continue_overrides_break()

# a break inside an inner finally still runs the enclosing finally.
def break_inside_inner_finally():
 out = []
 for i in range(3):
 try:
 try:
 out.append(("inner-body", i))
 finally:
 out.append(("inner-fin", i))
 if i == 1:
 break
 finally:
 out.append(("outer-fin", i))
 return out

assert break_inside_inner_finally() == [
 ("inner-body", 0), ("inner-fin", 0), ("outer-fin", 0),
 ("inner-body", 1), ("inner-fin", 1), ("outer-fin", 1),
], break_inside_inner_finally()

print("break_continue_in_try: ok")
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mlir: fix break/continue inside a try/with#27

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 Merged

gf712
merged 1 commit into

from

Jun 28, 2026
 Merged


mlir: fix break/continue inside a try/with
#27
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288 changes: 288 additions & 0 deletions
integration/tests/break_continue_in_try.py

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,288 @@
# Regression test: `break`/`continue` that leaves a `try`/`except` or `with`
# block inside a loop. These previously produced a `cf.br` from inside the
# still-nested python.try/with region to a block in the enclosing loop region
# (an invalid cross-region branch), which sent MLIR's region DCE into unbounded
# recursion and crashed the compiler. os.py's removedirs()/_walk() hit this,
# so `import os` segfaulted.

# break out of an except handler (while) -- the removedirs() shape.
def break_in_except_while(items):
 out = []
 i = 0
 while i < 5:
 try:
 out.append(items[i])
 except IndexError:
 break
 i += 1
 return out

assert break_in_except_while([10, 20]) == [10, 20], break_in_except_while([10, 20])

# continue out of an except handler (for).
def continue_in_except_for(items):
 out = []
 for x in items:
 try:
 if x == 0:
 raise ValueError("zero")
 out.append(x)
 except ValueError:
 continue
 return out

assert continue_in_except_for([1, 0, 2, 0, 5]) == [1, 2, 5], continue_in_except_for([1, 0, 2, 0, 5])

# break from the try body itself (not from a handler).
def break_in_try_body():
 out = []
 i = 0
 while i < 10:
 try:
 out.append(i)
 if i == 3:
 break
 except Exception:
 out.append(-1)
 i += 1
 return out

assert break_in_try_body() == [0, 1, 2, 3], break_in_try_body()

# break/continue out of a `with` must still run __exit__.
class CM:
 def __init__(self, log):
 self._log = log
 def __enter__(self):
 self._log.append("enter")
 return self
 def __exit__(self, *a):
 self._log.append("exit")
 return False

def break_out_of_with():
 log = []
 i = 0
 while i < 3:
 with CM(log):
 if i == 1:
 break
 i += 1
 return log

assert break_out_of_with() == ["enter", "exit", "enter", "exit"], break_out_of_with()

def continue_out_of_with():
 log = []
 for i in range(3):
 with CM(log):
 if i == 1:
 continue
 log.append(("after", i))
 return log

assert continue_out_of_with() == [
 "enter", "exit", ("after", 0),
 "enter", "exit",
 "enter", "exit", ("after", 2),
], continue_out_of_with()

# nested try/except with break in the inner handler -- the _walk() shape.
def nested_try_break(values):
 out = []
 it = iter(values)
 while True:
 try:
 try:
 v = next(it)
 except StopIteration:
 break
 except RuntimeError:
 out.append("runtime")
 continue
 out.append(v)
 return out

assert nested_try_break([1, 2, 3]) == [1, 2, 3], nested_try_break([1, 2, 3])

# break/continue out of a try must still run its finally first.
def break_in_except_with_finally():
 out = []
 i = 0
 while i < 5:
 try:
 out.append(("body", i))
 raise ValueError
 except ValueError:
 out.append(("except", i))
 break
 finally:
 out.append(("finally", i))
 i += 1
 return out

assert break_in_except_with_finally() == [
 ("body", 0), ("except", 0), ("finally", 0),
], break_in_except_with_finally()

def continue_with_finally():
 out = []
 for i in range(3):
 try:
 if i == 1:
 raise ValueError
 out.append(("ok", i))
 except ValueError:
 continue
 finally:
 out.append(("fin", i))
 return out

assert continue_with_finally() == [
 ("ok", 0), ("fin", 0), ("fin", 1), ("ok", 2), ("fin", 2),
], continue_with_finally()

# both break and continue, each unwinding the same finally.
def break_and_continue_with_finally():
 out = []
 for i in range(6):
 try:
 if i == 1:
 continue
 if i == 4:
 break
 out.append(("ok", i))
 finally:
 out.append(("fin", i))
 return out

assert break_and_continue_with_finally() == [
 ("ok", 0), ("fin", 0),
 ("fin", 1),
 ("ok", 2), ("fin", 2),
 ("ok", 3), ("fin", 3),
 ("fin", 4),
], break_and_continue_with_finally()

# break from the try body (no exception raised) still runs finally.
def break_in_body_with_finally():
 out = []
 i = 0
 while i < 5:
 try:
 out.append(("body", i))
 if i == 2:
 break
 finally:
 out.append(("fin", i))
 i += 1
 return out

assert break_in_body_with_finally() == [
 ("body", 0), ("fin", 0),
 ("body", 1), ("fin", 1),
 ("body", 2), ("fin", 2),
], break_in_body_with_finally()

# break through *nested* try/finally runs every finally, innermost first.
def break_through_nested_finally():
 out = []
 i = 0
 while i < 4:
 try:
 try:
 out.append(("body", i))
 if i == 1:
 break
 finally:
 out.append(("inner-fin", i))
 finally:
 out.append(("outer-fin", i))
 i += 1
 return out

assert break_through_nested_finally() == [
 ("body", 0), ("inner-fin", 0), ("outer-fin", 0),
 ("body", 1), ("inner-fin", 1), ("outer-fin", 1),
], break_through_nested_finally()

# break written *inside* a finally exits the loop.
def break_inside_finally():
 out = []
 for i in range(4):
 try:
 out.append(("body", i))
 finally:
 out.append(("fin", i))
 if i == 1:
 break
 return out

assert break_inside_finally() == [
 ("body", 0), ("fin", 0), ("body", 1), ("fin", 1),
], break_inside_finally()

# a break inside a finally swallows an exception that is in flight -- even one
# raised by a called function.
def boom():
 raise RuntimeError("from callee")

def break_inside_finally_swallows_exception():
 out = []
 for i in range(4):
 try:
 out.append(("body", i))
 if i == 1:
 boom()
 finally:
 out.append(("fin", i))
 if i == 1:
 break
 return out

assert break_inside_finally_swallows_exception() == [
 ("body", 0), ("fin", 0), ("body", 1), ("fin", 1),
], break_inside_finally_swallows_exception()

# a continue inside a finally overrides a break in the try body.
def finally_continue_overrides_break():
 out = []
 for i in range(4):
 try:
 out.append(("body", i))
 if i == 1:
 break
 finally:
 out.append(("fin", i))
 if i == 1:
 continue
 return out

assert finally_continue_overrides_break() == [
 ("body", 0), ("fin", 0),
 ("body", 1), ("fin", 1),
 ("body", 2), ("fin", 2),
 ("body", 3), ("fin", 3),
], finally_continue_overrides_break()

# a break inside an inner finally still runs the enclosing finally.
def break_inside_inner_finally():
 out = []
 for i in range(3):
 try:
 try:
 out.append(("inner-body", i))
 finally:
 out.append(("inner-fin", i))
 if i == 1:
 break
 finally:
 out.append(("outer-fin", i))
 return out

assert break_inside_inner_finally() == [
 ("inner-body", 0), ("inner-fin", 0), ("outer-fin", 0),
 ("inner-body", 1), ("inner-fin", 1), ("outer-fin", 1),
], break_inside_inner_finally()

print("break_continue_in_try: ok")
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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mlir: fix break/continue inside a try/with#27

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Jun 28, 2026
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mlir: fix break/continue inside a try/with
#27
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288 changes: 288 additions & 0 deletions
integration/tests/break_continue_in_try.py

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,288 @@
# Regression test: `break`/`continue` that leaves a `try`/`except` or `with`
# block inside a loop. These previously produced a `cf.br` from inside the
# still-nested python.try/with region to a block in the enclosing loop region
# (an invalid cross-region branch), which sent MLIR's region DCE into unbounded
# recursion and crashed the compiler. os.py's removedirs()/_walk() hit this,
# so `import os` segfaulted.

# break out of an except handler (while) -- the removedirs() shape.
def break_in_except_while(items):
 out = []
 i = 0
 while i < 5:
 try:
 out.append(items[i])
 except IndexError:
 break
 i += 1
 return out

assert break_in_except_while([10, 20]) == [10, 20], break_in_except_while([10, 20])

# continue out of an except handler (for).
def continue_in_except_for(items):
 out = []
 for x in items:
 try:
 if x == 0:
 raise ValueError("zero")
 out.append(x)
 except ValueError:
 continue
 return out

assert continue_in_except_for([1, 0, 2, 0, 5]) == [1, 2, 5], continue_in_except_for([1, 0, 2, 0, 5])

# break from the try body itself (not from a handler).
def break_in_try_body():
 out = []
 i = 0
 while i < 10:
 try:
 out.append(i)
 if i == 3:
 break
 except Exception:
 out.append(-1)
 i += 1
 return out

assert break_in_try_body() == [0, 1, 2, 3], break_in_try_body()

# break/continue out of a `with` must still run __exit__.
class CM:
 def __init__(self, log):
 self._log = log
 def __enter__(self):
 self._log.append("enter")
 return self
 def __exit__(self, *a):
 self._log.append("exit")
 return False

def break_out_of_with():
 log = []
 i = 0
 while i < 3:
 with CM(log):
 if i == 1:
 break
 i += 1
 return log

assert break_out_of_with() == ["enter", "exit", "enter", "exit"], break_out_of_with()

def continue_out_of_with():
 log = []
 for i in range(3):
 with CM(log):
 if i == 1:
 continue
 log.append(("after", i))
 return log

assert continue_out_of_with() == [
 "enter", "exit", ("after", 0),
 "enter", "exit",
 "enter", "exit", ("after", 2),
], continue_out_of_with()

# nested try/except with break in the inner handler -- the _walk() shape.
def nested_try_break(values):
 out = []
 it = iter(values)
 while True:
 try:
 try:
 v = next(it)
 except StopIteration:
 break
 except RuntimeError:
 out.append("runtime")
 continue
 out.append(v)
 return out

assert nested_try_break([1, 2, 3]) == [1, 2, 3], nested_try_break([1, 2, 3])

# break/continue out of a try must still run its finally first.
def break_in_except_with_finally():
 out = []
 i = 0
 while i < 5:
 try:
 out.append(("body", i))
 raise ValueError
 except ValueError:
 out.append(("except", i))
 break
 finally:
 out.append(("finally", i))
 i += 1
 return out

assert break_in_except_with_finally() == [
 ("body", 0), ("except", 0), ("finally", 0),
], break_in_except_with_finally()

def continue_with_finally():
 out = []
 for i in range(3):
 try:
 if i == 1:
 raise ValueError
 out.append(("ok", i))
 except ValueError:
 continue
 finally:
 out.append(("fin", i))
 return out

assert continue_with_finally() == [
 ("ok", 0), ("fin", 0), ("fin", 1), ("ok", 2), ("fin", 2),
], continue_with_finally()

# both break and continue, each unwinding the same finally.
def break_and_continue_with_finally():
 out = []
 for i in range(6):
 try:
 if i == 1:
 continue
 if i == 4:
 break
 out.append(("ok", i))
 finally:
 out.append(("fin", i))
 return out

assert break_and_continue_with_finally() == [
 ("ok", 0), ("fin", 0),
 ("fin", 1),
 ("ok", 2), ("fin", 2),
 ("ok", 3), ("fin", 3),
 ("fin", 4),
], break_and_continue_with_finally()

# break from the try body (no exception raised) still runs finally.
def break_in_body_with_finally():
 out = []
 i = 0
 while i < 5:
 try:
 out.append(("body", i))
 if i == 2:
 break
 finally:
 out.append(("fin", i))
 i += 1
 return out

assert break_in_body_with_finally() == [
 ("body", 0), ("fin", 0),
 ("body", 1), ("fin", 1),
 ("body", 2), ("fin", 2),
], break_in_body_with_finally()

# break through *nested* try/finally runs every finally, innermost first.
def break_through_nested_finally():
 out = []
 i = 0
 while i < 4:
 try:
 try:
 out.append(("body", i))
 if i == 1:
 break
 finally:
 out.append(("inner-fin", i))
 finally:
 out.append(("outer-fin", i))
 i += 1
 return out

assert break_through_nested_finally() == [
 ("body", 0), ("inner-fin", 0), ("outer-fin", 0),
 ("body", 1), ("inner-fin", 1), ("outer-fin", 1),
], break_through_nested_finally()

# break written *inside* a finally exits the loop.
def break_inside_finally():
 out = []
 for i in range(4):
 try:
 out.append(("body", i))
 finally:
 out.append(("fin", i))
 if i == 1:
 break
 return out

assert break_inside_finally() == [
 ("body", 0), ("fin", 0), ("body", 1), ("fin", 1),
], break_inside_finally()

# a break inside a finally swallows an exception that is in flight -- even one
# raised by a called function.
def boom():
 raise RuntimeError("from callee")

def break_inside_finally_swallows_exception():
 out = []
 for i in range(4):
 try:
 out.append(("body", i))
 if i == 1:
 boom()
 finally:
 out.append(("fin", i))
 if i == 1:
 break
 return out

assert break_inside_finally_swallows_exception() == [
 ("body", 0), ("fin", 0), ("body", 1), ("fin", 1),
], break_inside_finally_swallows_exception()

# a continue inside a finally overrides a break in the try body.
def finally_continue_overrides_break():
 out = []
 for i in range(4):
 try:
 out.append(("body", i))
 if i == 1:
 break
 finally:
 out.append(("fin", i))
 if i == 1:
 continue
 return out

assert finally_continue_overrides_break() == [
 ("body", 0), ("fin", 0),
 ("body", 1), ("fin", 1),
 ("body", 2), ("fin", 2),
 ("body", 3), ("fin", 3),
], finally_continue_overrides_break()

# a break inside an inner finally still runs the enclosing finally.
def break_inside_inner_finally():
 out = []
 for i in range(3):
 try:
 try:
 out.append(("inner-body", i))
 finally:
 out.append(("inner-fin", i))
 if i == 1:
 break
 finally:
 out.append(("outer-fin", i))
 return out

assert break_inside_inner_finally() == [
 ("inner-body", 0), ("inner-fin", 0), ("outer-fin", 0),
 ("inner-body", 1), ("inner-fin", 1), ("outer-fin", 1),
], break_inside_inner_finally()

print("break_continue_in_try: ok")
Loading
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

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mlir: fix break/continue inside a try/with#27

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gf712
merged 1 commit into

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Jun 28, 2026
 Merged


mlir: fix break/continue inside a try/with
#27
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288 changes: 288 additions & 0 deletions
integration/tests/break_continue_in_try.py

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,288 @@
# Regression test: `break`/`continue` that leaves a `try`/`except` or `with`
# block inside a loop. These previously produced a `cf.br` from inside the
# still-nested python.try/with region to a block in the enclosing loop region
# (an invalid cross-region branch), which sent MLIR's region DCE into unbounded
# recursion and crashed the compiler. os.py's removedirs()/_walk() hit this,
# so `import os` segfaulted.

# break out of an except handler (while) -- the removedirs() shape.
def break_in_except_while(items):
 out = []
 i = 0
 while i < 5:
 try:
 out.append(items[i])
 except IndexError:
 break
 i += 1
 return out

assert break_in_except_while([10, 20]) == [10, 20], break_in_except_while([10, 20])

# continue out of an except handler (for).
def continue_in_except_for(items):
 out = []
 for x in items:
 try:
 if x == 0:
 raise ValueError("zero")
 out.append(x)
 except ValueError:
 continue
 return out

assert continue_in_except_for([1, 0, 2, 0, 5]) == [1, 2, 5], continue_in_except_for([1, 0, 2, 0, 5])

# break from the try body itself (not from a handler).
def break_in_try_body():
 out = []
 i = 0
 while i < 10:
 try:
 out.append(i)
 if i == 3:
 break
 except Exception:
 out.append(-1)
 i += 1
 return out

assert break_in_try_body() == [0, 1, 2, 3], break_in_try_body()

# break/continue out of a `with` must still run __exit__.
class CM:
 def __init__(self, log):
 self._log = log
 def __enter__(self):
 self._log.append("enter")
 return self
 def __exit__(self, *a):
 self._log.append("exit")
 return False

def break_out_of_with():
 log = []
 i = 0
 while i < 3:
 with CM(log):
 if i == 1:
 break
 i += 1
 return log

assert break_out_of_with() == ["enter", "exit", "enter", "exit"], break_out_of_with()

def continue_out_of_with():
 log = []
 for i in range(3):
 with CM(log):
 if i == 1:
 continue
 log.append(("after", i))
 return log

assert continue_out_of_with() == [
 "enter", "exit", ("after", 0),
 "enter", "exit",
 "enter", "exit", ("after", 2),
], continue_out_of_with()

# nested try/except with break in the inner handler -- the _walk() shape.
def nested_try_break(values):
 out = []
 it = iter(values)
 while True:
 try:
 try:
 v = next(it)
 except StopIteration:
 break
 except RuntimeError:
 out.append("runtime")
 continue
 out.append(v)
 return out

assert nested_try_break([1, 2, 3]) == [1, 2, 3], nested_try_break([1, 2, 3])

# break/continue out of a try must still run its finally first.
def break_in_except_with_finally():
 out = []
 i = 0
 while i < 5:
 try:
 out.append(("body", i))
 raise ValueError
 except ValueError:
 out.append(("except", i))
 break
 finally:
 out.append(("finally", i))
 i += 1
 return out

assert break_in_except_with_finally() == [
 ("body", 0), ("except", 0), ("finally", 0),
], break_in_except_with_finally()

def continue_with_finally():
 out = []
 for i in range(3):
 try:
 if i == 1:
 raise ValueError
 out.append(("ok", i))
 except ValueError:
 continue
 finally:
 out.append(("fin", i))
 return out

assert continue_with_finally() == [
 ("ok", 0), ("fin", 0), ("fin", 1), ("ok", 2), ("fin", 2),
], continue_with_finally()

# both break and continue, each unwinding the same finally.
def break_and_continue_with_finally():
 out = []
 for i in range(6):
 try:
 if i == 1:
 continue
 if i == 4:
 break
 out.append(("ok", i))
 finally:
 out.append(("fin", i))
 return out

assert break_and_continue_with_finally() == [
 ("ok", 0), ("fin", 0),
 ("fin", 1),
 ("ok", 2), ("fin", 2),
 ("ok", 3), ("fin", 3),
 ("fin", 4),
], break_and_continue_with_finally()

# break from the try body (no exception raised) still runs finally.
def break_in_body_with_finally():
 out = []
 i = 0
 while i < 5:
 try:
 out.append(("body", i))
 if i == 2:
 break
 finally:
 out.append(("fin", i))
 i += 1
 return out

assert break_in_body_with_finally() == [
 ("body", 0), ("fin", 0),
 ("body", 1), ("fin", 1),
 ("body", 2), ("fin", 2),
], break_in_body_with_finally()

# break through *nested* try/finally runs every finally, innermost first.
def break_through_nested_finally():
 out = []
 i = 0
 while i < 4:
 try:
 try:
 out.append(("body", i))
 if i == 1:
 break
 finally:
 out.append(("inner-fin", i))
 finally:
 out.append(("outer-fin", i))
 i += 1
 return out

assert break_through_nested_finally() == [
 ("body", 0), ("inner-fin", 0), ("outer-fin", 0),
 ("body", 1), ("inner-fin", 1), ("outer-fin", 1),
], break_through_nested_finally()

# break written *inside* a finally exits the loop.
def break_inside_finally():
 out = []
 for i in range(4):
 try:
 out.append(("body", i))
 finally:
 out.append(("fin", i))
 if i == 1:
 break
 return out

assert break_inside_finally() == [
 ("body", 0), ("fin", 0), ("body", 1), ("fin", 1),
], break_inside_finally()

# a break inside a finally swallows an exception that is in flight -- even one
# raised by a called function.
def boom():
 raise RuntimeError("from callee")

def break_inside_finally_swallows_exception():
 out = []
 for i in range(4):
 try:
 out.append(("body", i))
 if i == 1:
 boom()
 finally:
 out.append(("fin", i))
 if i == 1:
 break
 return out

assert break_inside_finally_swallows_exception() == [
 ("body", 0), ("fin", 0), ("body", 1), ("fin", 1),
], break_inside_finally_swallows_exception()

# a continue inside a finally overrides a break in the try body.
def finally_continue_overrides_break():
 out = []
 for i in range(4):
 try:
 out.append(("body", i))
 if i == 1:
 break
 finally:
 out.append(("fin", i))
 if i == 1:
 continue
 return out

assert finally_continue_overrides_break() == [
 ("body", 0), ("fin", 0),
 ("body", 1), ("fin", 1),
 ("body", 2), ("fin", 2),
 ("body", 3), ("fin", 3),
], finally_continue_overrides_break()

# a break inside an inner finally still runs the enclosing finally.
def break_inside_inner_finally():
 out = []
 for i in range(3):
 try:
 try:
 out.append(("inner-body", i))
 finally:
 out.append(("inner-fin", i))
 if i == 1:
 break
 finally:
 out.append(("outer-fin", i))
 return out

assert break_inside_inner_finally() == [
 ("inner-body", 0), ("inner-fin", 0), ("outer-fin", 0),
 ("inner-body", 1), ("inner-fin", 1), ("outer-fin", 1),
], break_inside_inner_finally()

print("break_continue_in_try: ok")
Loading
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
mlir: fix break/continue inside a try/with#27

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Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

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 Merged

gf712
merged 1 commit into

from

Jun 28, 2026
 Merged


mlir: fix break/continue inside a try/with
#27
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288 changes: 288 additions & 0 deletions
integration/tests/break_continue_in_try.py

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,288 @@
# Regression test: `break`/`continue` that leaves a `try`/`except` or `with`
# block inside a loop. These previously produced a `cf.br` from inside the
# still-nested python.try/with region to a block in the enclosing loop region
# (an invalid cross-region branch), which sent MLIR's region DCE into unbounded
# recursion and crashed the compiler. os.py's removedirs()/_walk() hit this,
# so `import os` segfaulted.

# break out of an except handler (while) -- the removedirs() shape.
def break_in_except_while(items):
 out = []
 i = 0
 while i < 5:
 try:
 out.append(items[i])
 except IndexError:
 break
 i += 1
 return out

assert break_in_except_while([10, 20]) == [10, 20], break_in_except_while([10, 20])

# continue out of an except handler (for).
def continue_in_except_for(items):
 out = []
 for x in items:
 try:
 if x == 0:
 raise ValueError("zero")
 out.append(x)
 except ValueError:
 continue
 return out

assert continue_in_except_for([1, 0, 2, 0, 5]) == [1, 2, 5], continue_in_except_for([1, 0, 2, 0, 5])

# break from the try body itself (not from a handler).
def break_in_try_body():
 out = []
 i = 0
 while i < 10:
 try:
 out.append(i)
 if i == 3:
 break
 except Exception:
 out.append(-1)
 i += 1
 return out

assert break_in_try_body() == [0, 1, 2, 3], break_in_try_body()

# break/continue out of a `with` must still run __exit__.
class CM:
 def __init__(self, log):
 self._log = log
 def __enter__(self):
 self._log.append("enter")
 return self
 def __exit__(self, *a):
 self._log.append("exit")
 return False

def break_out_of_with():
 log = []
 i = 0
 while i < 3:
 with CM(log):
 if i == 1:
 break
 i += 1
 return log

assert break_out_of_with() == ["enter", "exit", "enter", "exit"], break_out_of_with()

def continue_out_of_with():
 log = []
 for i in range(3):
 with CM(log):
 if i == 1:
 continue
 log.append(("after", i))
 return log

assert continue_out_of_with() == [
 "enter", "exit", ("after", 0),
 "enter", "exit",
 "enter", "exit", ("after", 2),
], continue_out_of_with()

# nested try/except with break in the inner handler -- the _walk() shape.
def nested_try_break(values):
 out = []
 it = iter(values)
 while True:
 try:
 try:
 v = next(it)
 except StopIteration:
 break
 except RuntimeError:
 out.append("runtime")
 continue
 out.append(v)
 return out

assert nested_try_break([1, 2, 3]) == [1, 2, 3], nested_try_break([1, 2, 3])

# break/continue out of a try must still run its finally first.
def break_in_except_with_finally():
 out = []
 i = 0
 while i < 5:
 try:
 out.append(("body", i))
 raise ValueError
 except ValueError:
 out.append(("except", i))
 break
 finally:
 out.append(("finally", i))
 i += 1
 return out

assert break_in_except_with_finally() == [
 ("body", 0), ("except", 0), ("finally", 0),
], break_in_except_with_finally()

def continue_with_finally():
 out = []
 for i in range(3):
 try:
 if i == 1:
 raise ValueError
 out.append(("ok", i))
 except ValueError:
 continue
 finally:
 out.append(("fin", i))
 return out

assert continue_with_finally() == [
 ("ok", 0), ("fin", 0), ("fin", 1), ("ok", 2), ("fin", 2),
], continue_with_finally()

# both break and continue, each unwinding the same finally.
def break_and_continue_with_finally():
 out = []
 for i in range(6):
 try:
 if i == 1:
 continue
 if i == 4:
 break
 out.append(("ok", i))
 finally:
 out.append(("fin", i))
 return out

assert break_and_continue_with_finally() == [
 ("ok", 0), ("fin", 0),
 ("fin", 1),
 ("ok", 2), ("fin", 2),
 ("ok", 3), ("fin", 3),
 ("fin", 4),
], break_and_continue_with_finally()

# break from the try body (no exception raised) still runs finally.
def break_in_body_with_finally():
 out = []
 i = 0
 while i < 5:
 try:
 out.append(("body", i))
 if i == 2:
 break
 finally:
 out.append(("fin", i))
 i += 1
 return out

assert break_in_body_with_finally() == [
 ("body", 0), ("fin", 0),
 ("body", 1), ("fin", 1),
 ("body", 2), ("fin", 2),
], break_in_body_with_finally()

# break through *nested* try/finally runs every finally, innermost first.
def break_through_nested_finally():
 out = []
 i = 0
 while i < 4:
 try:
 try:
 out.append(("body", i))
 if i == 1:
 break
 finally:
 out.append(("inner-fin", i))
 finally:
 out.append(("outer-fin", i))
 i += 1
 return out

assert break_through_nested_finally() == [
 ("body", 0), ("inner-fin", 0), ("outer-fin", 0),
 ("body", 1), ("inner-fin", 1), ("outer-fin", 1),
], break_through_nested_finally()

# break written *inside* a finally exits the loop.
def break_inside_finally():
 out = []
 for i in range(4):
 try:
 out.append(("body", i))
 finally:
 out.append(("fin", i))
 if i == 1:
 break
 return out

assert break_inside_finally() == [
 ("body", 0), ("fin", 0), ("body", 1), ("fin", 1),
], break_inside_finally()

# a break inside a finally swallows an exception that is in flight -- even one
# raised by a called function.
def boom():
 raise RuntimeError("from callee")

def break_inside_finally_swallows_exception():
 out = []
 for i in range(4):
 try:
 out.append(("body", i))
 if i == 1:
 boom()
 finally:
 out.append(("fin", i))
 if i == 1:
 break
 return out

assert break_inside_finally_swallows_exception() == [
 ("body", 0), ("fin", 0), ("body", 1), ("fin", 1),
], break_inside_finally_swallows_exception()

# a continue inside a finally overrides a break in the try body.
def finally_continue_overrides_break():
 out = []
 for i in range(4):
 try:
 out.append(("body", i))
 if i == 1:
 break
 finally:
 out.append(("fin", i))
 if i == 1:
 continue
 return out

assert finally_continue_overrides_break() == [
 ("body", 0), ("fin", 0),
 ("body", 1), ("fin", 1),
 ("body", 2), ("fin", 2),
 ("body", 3), ("fin", 3),
], finally_continue_overrides_break()

# a break inside an inner finally still runs the enclosing finally.
def break_inside_inner_finally():
 out = []
 for i in range(3):
 try:
 try:
 out.append(("inner-body", i))
 finally:
 out.append(("inner-fin", i))
 if i == 1:
 break
 finally:
 out.append(("outer-fin", i))
 return out

assert break_inside_inner_finally() == [
 ("inner-body", 0), ("inner-fin", 0), ("outer-fin", 0),
 ("inner-body", 1), ("inner-fin", 1), ("outer-fin", 1),
], break_inside_inner_finally()

print("break_continue_in_try: ok")
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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mlir: fix break/continue inside a try/with#27

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Jun 28, 2026
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mlir: fix break/continue inside a try/with
#27
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288 changes: 288 additions & 0 deletions
integration/tests/break_continue_in_try.py

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,288 @@
# Regression test: `break`/`continue` that leaves a `try`/`except` or `with`
# block inside a loop. These previously produced a `cf.br` from inside the
# still-nested python.try/with region to a block in the enclosing loop region
# (an invalid cross-region branch), which sent MLIR's region DCE into unbounded
# recursion and crashed the compiler. os.py's removedirs()/_walk() hit this,
# so `import os` segfaulted.

# break out of an except handler (while) -- the removedirs() shape.
def break_in_except_while(items):
 out = []
 i = 0
 while i < 5:
 try:
 out.append(items[i])
 except IndexError:
 break
 i += 1
 return out

assert break_in_except_while([10, 20]) == [10, 20], break_in_except_while([10, 20])

# continue out of an except handler (for).
def continue_in_except_for(items):
 out = []
 for x in items:
 try:
 if x == 0:
 raise ValueError("zero")
 out.append(x)
 except ValueError:
 continue
 return out

assert continue_in_except_for([1, 0, 2, 0, 5]) == [1, 2, 5], continue_in_except_for([1, 0, 2, 0, 5])

# break from the try body itself (not from a handler).
def break_in_try_body():
 out = []
 i = 0
 while i < 10:
 try:
 out.append(i)
 if i == 3:
 break
 except Exception:
 out.append(-1)
 i += 1
 return out

assert break_in_try_body() == [0, 1, 2, 3], break_in_try_body()

# break/continue out of a `with` must still run __exit__.
class CM:
 def __init__(self, log):
 self._log = log
 def __enter__(self):
 self._log.append("enter")
 return self
 def __exit__(self, *a):
 self._log.append("exit")
 return False

def break_out_of_with():
 log = []
 i = 0
 while i < 3:
 with CM(log):
 if i == 1:
 break
 i += 1
 return log

assert break_out_of_with() == ["enter", "exit", "enter", "exit"], break_out_of_with()

def continue_out_of_with():
 log = []
 for i in range(3):
 with CM(log):
 if i == 1:
 continue
 log.append(("after", i))
 return log

assert continue_out_of_with() == [
 "enter", "exit", ("after", 0),
 "enter", "exit",
 "enter", "exit", ("after", 2),
], continue_out_of_with()

# nested try/except with break in the inner handler -- the _walk() shape.
def nested_try_break(values):
 out = []
 it = iter(values)
 while True:
 try:
 try:
 v = next(it)
 except StopIteration:
 break
 except RuntimeError:
 out.append("runtime")
 continue
 out.append(v)
 return out

assert nested_try_break([1, 2, 3]) == [1, 2, 3], nested_try_break([1, 2, 3])

# break/continue out of a try must still run its finally first.
def break_in_except_with_finally():
 out = []
 i = 0
 while i < 5:
 try:
 out.append(("body", i))
 raise ValueError
 except ValueError:
 out.append(("except", i))
 break
 finally:
 out.append(("finally", i))
 i += 1
 return out

assert break_in_except_with_finally() == [
 ("body", 0), ("except", 0), ("finally", 0),
], break_in_except_with_finally()

def continue_with_finally():
 out = []
 for i in range(3):
 try:
 if i == 1:
 raise ValueError
 out.append(("ok", i))
 except ValueError:
 continue
 finally:
 out.append(("fin", i))
 return out

assert continue_with_finally() == [
 ("ok", 0), ("fin", 0), ("fin", 1), ("ok", 2), ("fin", 2),
], continue_with_finally()

# both break and continue, each unwinding the same finally.
def break_and_continue_with_finally():
 out = []
 for i in range(6):
 try:
 if i == 1:
 continue
 if i == 4:
 break
 out.append(("ok", i))
 finally:
 out.append(("fin", i))
 return out

assert break_and_continue_with_finally() == [
 ("ok", 0), ("fin", 0),
 ("fin", 1),
 ("ok", 2), ("fin", 2),
 ("ok", 3), ("fin", 3),
 ("fin", 4),
], break_and_continue_with_finally()

# break from the try body (no exception raised) still runs finally.
def break_in_body_with_finally():
 out = []
 i = 0
 while i < 5:
 try:
 out.append(("body", i))
 if i == 2:
 break
 finally:
 out.append(("fin", i))
 i += 1
 return out

assert break_in_body_with_finally() == [
 ("body", 0), ("fin", 0),
 ("body", 1), ("fin", 1),
 ("body", 2), ("fin", 2),
], break_in_body_with_finally()

# break through *nested* try/finally runs every finally, innermost first.
def break_through_nested_finally():
 out = []
 i = 0
 while i < 4:
 try:
 try:
 out.append(("body", i))
 if i == 1:
 break
 finally:
 out.append(("inner-fin", i))
 finally:
 out.append(("outer-fin", i))
 i += 1
 return out

assert break_through_nested_finally() == [
 ("body", 0), ("inner-fin", 0), ("outer-fin", 0),
 ("body", 1), ("inner-fin", 1), ("outer-fin", 1),
], break_through_nested_finally()

# break written *inside* a finally exits the loop.
def break_inside_finally():
 out = []
 for i in range(4):
 try:
 out.append(("body", i))
 finally:
 out.append(("fin", i))
 if i == 1:
 break
 return out

assert break_inside_finally() == [
 ("body", 0), ("fin", 0), ("body", 1), ("fin", 1),
], break_inside_finally()

# a break inside a finally swallows an exception that is in flight -- even one
# raised by a called function.
def boom():
 raise RuntimeError("from callee")

def break_inside_finally_swallows_exception():
 out = []
 for i in range(4):
 try:
 out.append(("body", i))
 if i == 1:
 boom()
 finally:
 out.append(("fin", i))
 if i == 1:
 break
 return out

assert break_inside_finally_swallows_exception() == [
 ("body", 0), ("fin", 0), ("body", 1), ("fin", 1),
], break_inside_finally_swallows_exception()

# a continue inside a finally overrides a break in the try body.
def finally_continue_overrides_break():
 out = []
 for i in range(4):
 try:
 out.append(("body", i))
 if i == 1:
 break
 finally:
 out.append(("fin", i))
 if i == 1:
 continue
 return out

assert finally_continue_overrides_break() == [
 ("body", 0), ("fin", 0),
 ("body", 1), ("fin", 1),
 ("body", 2), ("fin", 2),
 ("body", 3), ("fin", 3),
], finally_continue_overrides_break()

# a break inside an inner finally still runs the enclosing finally.
def break_inside_inner_finally():
 out = []
 for i in range(3):
 try:
 try:
 out.append(("inner-body", i))
 finally:
 out.append(("inner-fin", i))
 if i == 1:
 break
 finally:
 out.append(("outer-fin", i))
 return out

assert break_inside_inner_finally() == [
 ("inner-body", 0), ("inner-fin", 0), ("outer-fin", 0),
 ("inner-body", 1), ("inner-fin", 1), ("outer-fin", 1),
], break_inside_inner_finally()

print("break_continue_in_try: ok")
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

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mlir: fix break/continue inside a try/with#27

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 Merged

gf712
merged 1 commit into

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Jun 28, 2026
 Merged


mlir: fix break/continue inside a try/with
#27
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288 changes: 288 additions & 0 deletions
integration/tests/break_continue_in_try.py

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,288 @@
# Regression test: `break`/`continue` that leaves a `try`/`except` or `with`
# block inside a loop. These previously produced a `cf.br` from inside the
# still-nested python.try/with region to a block in the enclosing loop region
# (an invalid cross-region branch), which sent MLIR's region DCE into unbounded
# recursion and crashed the compiler. os.py's removedirs()/_walk() hit this,
# so `import os` segfaulted.

# break out of an except handler (while) -- the removedirs() shape.
def break_in_except_while(items):
 out = []
 i = 0
 while i < 5:
 try:
 out.append(items[i])
 except IndexError:
 break
 i += 1
 return out

assert break_in_except_while([10, 20]) == [10, 20], break_in_except_while([10, 20])

# continue out of an except handler (for).
def continue_in_except_for(items):
 out = []
 for x in items:
 try:
 if x == 0:
 raise ValueError("zero")
 out.append(x)
 except ValueError:
 continue
 return out

assert continue_in_except_for([1, 0, 2, 0, 5]) == [1, 2, 5], continue_in_except_for([1, 0, 2, 0, 5])

# break from the try body itself (not from a handler).
def break_in_try_body():
 out = []
 i = 0
 while i < 10:
 try:
 out.append(i)
 if i == 3:
 break
 except Exception:
 out.append(-1)
 i += 1
 return out

assert break_in_try_body() == [0, 1, 2, 3], break_in_try_body()

# break/continue out of a `with` must still run __exit__.
class CM:
 def __init__(self, log):
 self._log = log
 def __enter__(self):
 self._log.append("enter")
 return self
 def __exit__(self, *a):
 self._log.append("exit")
 return False

def break_out_of_with():
 log = []
 i = 0
 while i < 3:
 with CM(log):
 if i == 1:
 break
 i += 1
 return log

assert break_out_of_with() == ["enter", "exit", "enter", "exit"], break_out_of_with()

def continue_out_of_with():
 log = []
 for i in range(3):
 with CM(log):
 if i == 1:
 continue
 log.append(("after", i))
 return log

assert continue_out_of_with() == [
 "enter", "exit", ("after", 0),
 "enter", "exit",
 "enter", "exit", ("after", 2),
], continue_out_of_with()

# nested try/except with break in the inner handler -- the _walk() shape.
def nested_try_break(values):
 out = []
 it = iter(values)
 while True:
 try:
 try:
 v = next(it)
 except StopIteration:
 break
 except RuntimeError:
 out.append("runtime")
 continue
 out.append(v)
 return out

assert nested_try_break([1, 2, 3]) == [1, 2, 3], nested_try_break([1, 2, 3])

# break/continue out of a try must still run its finally first.
def break_in_except_with_finally():
 out = []
 i = 0
 while i < 5:
 try:
 out.append(("body", i))
 raise ValueError
 except ValueError:
 out.append(("except", i))
 break
 finally:
 out.append(("finally", i))
 i += 1
 return out

assert break_in_except_with_finally() == [
 ("body", 0), ("except", 0), ("finally", 0),
], break_in_except_with_finally()

def continue_with_finally():
 out = []
 for i in range(3):
 try:
 if i == 1:
 raise ValueError
 out.append(("ok", i))
 except ValueError:
 continue
 finally:
 out.append(("fin", i))
 return out

assert continue_with_finally() == [
 ("ok", 0), ("fin", 0), ("fin", 1), ("ok", 2), ("fin", 2),
], continue_with_finally()

# both break and continue, each unwinding the same finally.
def break_and_continue_with_finally():
 out = []
 for i in range(6):
 try:
 if i == 1:
 continue
 if i == 4:
 break
 out.append(("ok", i))
 finally:
 out.append(("fin", i))
 return out

assert break_and_continue_with_finally() == [
 ("ok", 0), ("fin", 0),
 ("fin", 1),
 ("ok", 2), ("fin", 2),
 ("ok", 3), ("fin", 3),
 ("fin", 4),
], break_and_continue_with_finally()

# break from the try body (no exception raised) still runs finally.
def break_in_body_with_finally():
 out = []
 i = 0
 while i < 5:
 try:
 out.append(("body", i))
 if i == 2:
 break
 finally:
 out.append(("fin", i))
 i += 1
 return out

assert break_in_body_with_finally() == [
 ("body", 0), ("fin", 0),
 ("body", 1), ("fin", 1),
 ("body", 2), ("fin", 2),
], break_in_body_with_finally()

# break through *nested* try/finally runs every finally, innermost first.
def break_through_nested_finally():
 out = []
 i = 0
 while i < 4:
 try:
 try:
 out.append(("body", i))
 if i == 1:
 break
 finally:
 out.append(("inner-fin", i))
 finally:
 out.append(("outer-fin", i))
 i += 1
 return out

assert break_through_nested_finally() == [
 ("body", 0), ("inner-fin", 0), ("outer-fin", 0),
 ("body", 1), ("inner-fin", 1), ("outer-fin", 1),
], break_through_nested_finally()

# break written *inside* a finally exits the loop.
def break_inside_finally():
 out = []
 for i in range(4):
 try:
 out.append(("body", i))
 finally:
 out.append(("fin", i))
 if i == 1:
 break
 return out

assert break_inside_finally() == [
 ("body", 0), ("fin", 0), ("body", 1), ("fin", 1),
], break_inside_finally()

# a break inside a finally swallows an exception that is in flight -- even one
# raised by a called function.
def boom():
 raise RuntimeError("from callee")

def break_inside_finally_swallows_exception():
 out = []
 for i in range(4):
 try:
 out.append(("body", i))
 if i == 1:
 boom()
 finally:
 out.append(("fin", i))
 if i == 1:
 break
 return out

assert break_inside_finally_swallows_exception() == [
 ("body", 0), ("fin", 0), ("body", 1), ("fin", 1),
], break_inside_finally_swallows_exception()

# a continue inside a finally overrides a break in the try body.
def finally_continue_overrides_break():
 out = []
 for i in range(4):
 try:
 out.append(("body", i))
 if i == 1:
 break
 finally:
 out.append(("fin", i))
 if i == 1:
 continue
 return out

assert finally_continue_overrides_break() == [
 ("body", 0), ("fin", 0),
 ("body", 1), ("fin", 1),
 ("body", 2), ("fin", 2),
 ("body", 3), ("fin", 3),
], finally_continue_overrides_break()

# a break inside an inner finally still runs the enclosing finally.
def break_inside_inner_finally():
 out = []
 for i in range(3):
 try:
 try:
 out.append(("inner-body", i))
 finally:
 out.append(("inner-fin", i))
 if i == 1:
 break
 finally:
 out.append(("outer-fin", i))
 return out

assert break_inside_inner_finally() == [
 ("inner-body", 0), ("inner-fin", 0), ("outer-fin", 0),
 ("inner-body", 1), ("inner-fin", 1), ("outer-fin", 1),
], break_inside_inner_finally()

print("break_continue_in_try: ok")
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