fix: Fix per-file config interaction with one py_binary per main

CHANGELOG.md

@@ -40,6 +40,10 @@ A brief description of the categories of changes:
 * (toolchains) `py_runtime` can now take an executable target. Note: runfiles
  from the target are not supported yet.
 
+* (gazelle) When `python_generation_mode` is set to `file`, create one `py_binary`
+ target for each file with `if __name__ == "__main__"` instead of just one
+ `py_binary` for the whole module.
+
 ### Fixed
 
 * (gazelle) The gazelle plugin helper was not working with Python toolchains 3.11

gazelle/README.md

@@ -250,8 +250,20 @@ When no such entry point exists, Gazelle will look for a line like this in the t
 if __name == "__main__":
 ```
 
-Gazelle will create `py_binary` target will be created for every module with such line, with the target name
-being the same as module name.
+Gazelle will create a `py_binary` target for every module with such a line, with
+the target name the same as the module name.
+
+If `python_generation_mode` is set to `file`, then instead of one `py_binary`
+target per module, Gazelle will create one `py_binary` target for each file with
+such a line, and the name of the target will match the name of the script.
+
+Note that it's possible for another script to depend on a `py_binary` target and
+import from the `py_binary`'s scripts. This can have possible negative effects on
+Bazel analysis time and runfiles size compared to depending on a `py_library`
+target. The simplest way to avoid these negative effects is to extract library
+code into a separate script without a `main` line. Gazelle will then create a
+`py_library` target for that library code, and other scripts can depend on that
+`py_library` target.
 
 ## Developer Notes
 

gazelle/python/generate.go

@@ -225,23 +225,17 @@ func (py *Python) GenerateRules(args language.GenerateArgs) language.GenerateRes
  log.Fatalf("ERROR: %v\n", err)
  }
 
- // Check if a target with the same name we are generating already
- // exists, and if it is of a different kind from the one we are
- // generating. If so, we have to throw an error since Gazelle won't
- // generate it correctly.
- if err := ensureNoCollision(args.File, pyLibraryTargetName, actualPyLibraryKind); err != nil {
- fqTarget := label.New("", args.Rel, pyLibraryTargetName)
- err := fmt.Errorf("failed to generate target %q of kind %q: %w. "+
- "Use the '# gazelle:%s' directive to change the naming convention.",
- fqTarget.String(), actualPyLibraryKind, err, pythonconfig.LibraryNamingConvention)
- collisionErrors.Add(err)
- }
-
  if !hasPyBinaryEntryPointFile {
  // Creating one py_binary target per main module when __main__.py doesn't exist.
  mainFileNames := make([]string, 0, len(mainModules))
  for name := range mainModules {
  mainFileNames = append(mainFileNames, name)
+
+ // Remove the file from srcs if we're doing per-file library generation so
+ // that we don't also generate a py_library target for it.
+ if cfg.PerFileGeneration() {
+ srcs.Remove(name)
+ }
  }
  sort.Strings(mainFileNames)
  for _, filename := range mainFileNames {
@@ -262,6 +256,23 @@ func (py *Python) GenerateRules(args language.GenerateArgs) language.GenerateRes
  }
  }
 
+ // If we're doing per-file generation, srcs could be empty at this point, meaning we shouldn't make a py_library.
+ if srcs.Empty() {
+ return
+ }
+
+ // Check if a target with the same name we are generating already
+ // exists, and if it is of a different kind from the one we are
+ // generating. If so, we have to throw an error since Gazelle won't
+ // generate it correctly.
+ if err := ensureNoCollision(args.File, pyLibraryTargetName, actualPyLibraryKind); err != nil {
+ fqTarget := label.New("", args.Rel, pyLibraryTargetName)
+ err := fmt.Errorf("failed to generate target %q of kind %q: %w. "+
+ "Use the '# gazelle:%s' directive to change the naming convention.",
+ fqTarget.String(), actualPyLibraryKind, err, pythonconfig.LibraryNamingConvention)
+ collisionErrors.Add(err)
+ }
+
  pyLibrary := newTargetBuilder(pyLibraryKind, pyLibraryTargetName, pythonProjectRoot, args.Rel, pyFileNames).
  addVisibility(visibility).
  addSrcs(srcs).

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/BUILD.in

@@ -0,0 +1,4 @@
+# gazelle:python_generation_mode file
+
+# gazelle:resolve py numpy @pip//:numpy
+# gazelle:resolve py pandas @pip//:pandas

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/BUILD.out

@@ -0,0 +1,46 @@
+load("@rules_python//python:defs.bzl", "py_binary", "py_library")
+
+# gazelle:python_generation_mode file
+
+# gazelle:resolve py numpy @pip//:numpy
+# gazelle:resolve py pandas @pip//:pandas
+
+py_library(
+ name = "lib",
+ srcs = ["lib.py"],
+ visibility = ["//:__subpackages__"],
+ deps = [
+ "@pip//:numpy",
+ "@pip//:pandas",
+ ],
+)
+
+py_library(
+ name = "lib2",
+ srcs = ["lib2.py"],
+ visibility = ["//:__subpackages__"],
+ deps = [
+ ":lib",
+ ":lib_and_main",
+ ],
+)
+
+py_binary(
+ name = "lib_and_main",
+ srcs = ["lib_and_main.py"],
+ visibility = ["//:__subpackages__"],
+)
+
+py_binary(
+ name = "main",
+ srcs = ["main.py"],
+ visibility = ["//:__subpackages__"],
+ deps = ["@pip//:pandas"],
+)
+
+py_binary(
+ name = "main2",
+ srcs = ["main2.py"],
+ visibility = ["//:__subpackages__"],
+ deps = [":lib2"],
+)

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/README.md

@@ -0,0 +1,4 @@
+# Binary without entrypoint
+
+This test case asserts that when there is no __main__.py, a py_binary is generated per file main module, and that this
+py_binary is instead of (not in addition to) any py_library target.

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/WORKSPACE

@@ -0,0 +1 @@
+# This is a Bazel workspace for the Gazelle test data.

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/lib.py

@@ -0,0 +1,2 @@
+import numpy
+import pandas

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/lib2.py

@@ -0,0 +1,2 @@
+import lib
+import lib_and_main

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/lib_and_main.py

@@ -0,0 +1,6 @@
+def library_func():
+ print("library_func")
+
+
+if __name__ == "__main__":
+ library_func()

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/main.py

@@ -0,0 +1,4 @@
+import pandas
+
+if __name__ == "__main__":
+ run()

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/main2.py

@@ -0,0 +1,4 @@
+import lib2
+
+if __name__ == "__main__":
+ lib2.lib_and_main.library_func()

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/test.yaml

@@ -0,0 +1,17 @@
+# Copyright 2023 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+---
+expect:
+ exit_code: 0

CHANGELOG.md

@@ -40,6 +40,10 @@ A brief description of the categories of changes:
 * (toolchains) `py_runtime` can now take an executable target. Note: runfiles
  from the target are not supported yet.
 
+* (gazelle) When `python_generation_mode` is set to `file`, create one `py_binary`
+ target for each file with `if __name__ == "__main__"` instead of just one
+ `py_binary` for the whole module.
+
 ### Fixed
 
 * (gazelle) The gazelle plugin helper was not working with Python toolchains 3.11

gazelle/README.md

@@ -250,8 +250,20 @@ When no such entry point exists, Gazelle will look for a line like this in the t
 if __name == "__main__":
 ```
 
-Gazelle will create `py_binary` target will be created for every module with such line, with the target name
-being the same as module name.
+Gazelle will create a `py_binary` target for every module with such a line, with
+the target name the same as the module name.
+
+If `python_generation_mode` is set to `file`, then instead of one `py_binary`
+target per module, Gazelle will create one `py_binary` target for each file with
+such a line, and the name of the target will match the name of the script.
+
+Note that it's possible for another script to depend on a `py_binary` target and
+import from the `py_binary`'s scripts. This can have possible negative effects on
+Bazel analysis time and runfiles size compared to depending on a `py_library`
+target. The simplest way to avoid these negative effects is to extract library
+code into a separate script without a `main` line. Gazelle will then create a
+`py_library` target for that library code, and other scripts can depend on that
+`py_library` target.
 
 ## Developer Notes
 

gazelle/python/generate.go

@@ -225,23 +225,17 @@ func (py *Python) GenerateRules(args language.GenerateArgs) language.GenerateRes
  log.Fatalf("ERROR: %v\n", err)
  }
 
- // Check if a target with the same name we are generating already
- // exists, and if it is of a different kind from the one we are
- // generating. If so, we have to throw an error since Gazelle won't
- // generate it correctly.
- if err := ensureNoCollision(args.File, pyLibraryTargetName, actualPyLibraryKind); err != nil {
- fqTarget := label.New("", args.Rel, pyLibraryTargetName)
- err := fmt.Errorf("failed to generate target %q of kind %q: %w. "+
- "Use the '# gazelle:%s' directive to change the naming convention.",
- fqTarget.String(), actualPyLibraryKind, err, pythonconfig.LibraryNamingConvention)
- collisionErrors.Add(err)
- }
-
  if !hasPyBinaryEntryPointFile {
  // Creating one py_binary target per main module when __main__.py doesn't exist.
  mainFileNames := make([]string, 0, len(mainModules))
  for name := range mainModules {
  mainFileNames = append(mainFileNames, name)
+
+ // Remove the file from srcs if we're doing per-file library generation so
+ // that we don't also generate a py_library target for it.
+ if cfg.PerFileGeneration() {
+ srcs.Remove(name)
+ }
  }
  sort.Strings(mainFileNames)
  for _, filename := range mainFileNames {
@@ -262,6 +256,23 @@ func (py *Python) GenerateRules(args language.GenerateArgs) language.GenerateRes
  }
  }
 
+ // If we're doing per-file generation, srcs could be empty at this point, meaning we shouldn't make a py_library.
+ if srcs.Empty() {
+ return
+ }
+
+ // Check if a target with the same name we are generating already
+ // exists, and if it is of a different kind from the one we are
+ // generating. If so, we have to throw an error since Gazelle won't
+ // generate it correctly.
+ if err := ensureNoCollision(args.File, pyLibraryTargetName, actualPyLibraryKind); err != nil {
+ fqTarget := label.New("", args.Rel, pyLibraryTargetName)
+ err := fmt.Errorf("failed to generate target %q of kind %q: %w. "+
+ "Use the '# gazelle:%s' directive to change the naming convention.",
+ fqTarget.String(), actualPyLibraryKind, err, pythonconfig.LibraryNamingConvention)
+ collisionErrors.Add(err)
+ }
+
  pyLibrary := newTargetBuilder(pyLibraryKind, pyLibraryTargetName, pythonProjectRoot, args.Rel, pyFileNames).
  addVisibility(visibility).
  addSrcs(srcs).

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/BUILD.in

@@ -0,0 +1,4 @@
+# gazelle:python_generation_mode file
+
+# gazelle:resolve py numpy @pip//:numpy
+# gazelle:resolve py pandas @pip//:pandas

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/BUILD.out

@@ -0,0 +1,46 @@
+load("@rules_python//python:defs.bzl", "py_binary", "py_library")
+
+# gazelle:python_generation_mode file
+
+# gazelle:resolve py numpy @pip//:numpy
+# gazelle:resolve py pandas @pip//:pandas
+
+py_library(
+ name = "lib",
+ srcs = ["lib.py"],
+ visibility = ["//:__subpackages__"],
+ deps = [
+ "@pip//:numpy",
+ "@pip//:pandas",
+ ],
+)
+
+py_library(
+ name = "lib2",
+ srcs = ["lib2.py"],
+ visibility = ["//:__subpackages__"],
+ deps = [
+ ":lib",
+ ":lib_and_main",
+ ],
+)
+
+py_binary(
+ name = "lib_and_main",
+ srcs = ["lib_and_main.py"],
+ visibility = ["//:__subpackages__"],
+)
+
+py_binary(
+ name = "main",
+ srcs = ["main.py"],
+ visibility = ["//:__subpackages__"],
+ deps = ["@pip//:pandas"],
+)
+
+py_binary(
+ name = "main2",
+ srcs = ["main2.py"],
+ visibility = ["//:__subpackages__"],
+ deps = [":lib2"],
+)

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/README.md

@@ -0,0 +1,4 @@
+# Binary without entrypoint
+
+This test case asserts that when there is no __main__.py, a py_binary is generated per file main module, and that this
+py_binary is instead of (not in addition to) any py_library target.

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/WORKSPACE

@@ -0,0 +1 @@
+# This is a Bazel workspace for the Gazelle test data.

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/lib.py

@@ -0,0 +1,2 @@
+import numpy
+import pandas

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/lib2.py

@@ -0,0 +1,2 @@
+import lib
+import lib_and_main

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/lib_and_main.py

@@ -0,0 +1,6 @@
+def library_func():
+ print("library_func")
+
+
+if __name__ == "__main__":
+ library_func()

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/main.py

@@ -0,0 +1,4 @@
+import pandas
+
+if __name__ == "__main__":
+ run()

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/main2.py

@@ -0,0 +1,4 @@
+import lib2
+
+if __name__ == "__main__":
+ lib2.lib_and_main.library_func()

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/test.yaml

@@ -0,0 +1,17 @@
+# Copyright 2023 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+---
+expect:
+ exit_code: 0

CHANGELOG.md

@@ -40,6 +40,10 @@ A brief description of the categories of changes:
 * (toolchains) `py_runtime` can now take an executable target. Note: runfiles
  from the target are not supported yet.
 
+* (gazelle) When `python_generation_mode` is set to `file`, create one `py_binary`
+ target for each file with `if __name__ == "__main__"` instead of just one
+ `py_binary` for the whole module.
+
 ### Fixed
 
 * (gazelle) The gazelle plugin helper was not working with Python toolchains 3.11

gazelle/README.md

@@ -250,8 +250,20 @@ When no such entry point exists, Gazelle will look for a line like this in the t
 if __name == "__main__":
 ```
 
-Gazelle will create `py_binary` target will be created for every module with such line, with the target name
-being the same as module name.
+Gazelle will create a `py_binary` target for every module with such a line, with
+the target name the same as the module name.
+
+If `python_generation_mode` is set to `file`, then instead of one `py_binary`
+target per module, Gazelle will create one `py_binary` target for each file with
+such a line, and the name of the target will match the name of the script.
+
+Note that it's possible for another script to depend on a `py_binary` target and
+import from the `py_binary`'s scripts. This can have possible negative effects on
+Bazel analysis time and runfiles size compared to depending on a `py_library`
+target. The simplest way to avoid these negative effects is to extract library
+code into a separate script without a `main` line. Gazelle will then create a
+`py_library` target for that library code, and other scripts can depend on that
+`py_library` target.
 
 ## Developer Notes
 

gazelle/python/generate.go

@@ -225,23 +225,17 @@ func (py *Python) GenerateRules(args language.GenerateArgs) language.GenerateRes
  log.Fatalf("ERROR: %v\n", err)
  }
 
- // Check if a target with the same name we are generating already
- // exists, and if it is of a different kind from the one we are
- // generating. If so, we have to throw an error since Gazelle won't
- // generate it correctly.
- if err := ensureNoCollision(args.File, pyLibraryTargetName, actualPyLibraryKind); err != nil {
- fqTarget := label.New("", args.Rel, pyLibraryTargetName)
- err := fmt.Errorf("failed to generate target %q of kind %q: %w. "+
- "Use the '# gazelle:%s' directive to change the naming convention.",
- fqTarget.String(), actualPyLibraryKind, err, pythonconfig.LibraryNamingConvention)
- collisionErrors.Add(err)
- }
-
  if !hasPyBinaryEntryPointFile {
  // Creating one py_binary target per main module when __main__.py doesn't exist.
  mainFileNames := make([]string, 0, len(mainModules))
  for name := range mainModules {
  mainFileNames = append(mainFileNames, name)
+
+ // Remove the file from srcs if we're doing per-file library generation so
+ // that we don't also generate a py_library target for it.
+ if cfg.PerFileGeneration() {
+ srcs.Remove(name)
+ }
  }
  sort.Strings(mainFileNames)
  for _, filename := range mainFileNames {
@@ -262,6 +256,23 @@ func (py *Python) GenerateRules(args language.GenerateArgs) language.GenerateRes
  }
  }
 
+ // If we're doing per-file generation, srcs could be empty at this point, meaning we shouldn't make a py_library.
+ if srcs.Empty() {
+ return
+ }
+
+ // Check if a target with the same name we are generating already
+ // exists, and if it is of a different kind from the one we are
+ // generating. If so, we have to throw an error since Gazelle won't
+ // generate it correctly.
+ if err := ensureNoCollision(args.File, pyLibraryTargetName, actualPyLibraryKind); err != nil {
+ fqTarget := label.New("", args.Rel, pyLibraryTargetName)
+ err := fmt.Errorf("failed to generate target %q of kind %q: %w. "+
+ "Use the '# gazelle:%s' directive to change the naming convention.",
+ fqTarget.String(), actualPyLibraryKind, err, pythonconfig.LibraryNamingConvention)
+ collisionErrors.Add(err)
+ }
+
  pyLibrary := newTargetBuilder(pyLibraryKind, pyLibraryTargetName, pythonProjectRoot, args.Rel, pyFileNames).
  addVisibility(visibility).
  addSrcs(srcs).

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/BUILD.in

@@ -0,0 +1,4 @@
+# gazelle:python_generation_mode file
+
+# gazelle:resolve py numpy @pip//:numpy
+# gazelle:resolve py pandas @pip//:pandas

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/BUILD.out

@@ -0,0 +1,46 @@
+load("@rules_python//python:defs.bzl", "py_binary", "py_library")
+
+# gazelle:python_generation_mode file
+
+# gazelle:resolve py numpy @pip//:numpy
+# gazelle:resolve py pandas @pip//:pandas
+
+py_library(
+ name = "lib",
+ srcs = ["lib.py"],
+ visibility = ["//:__subpackages__"],
+ deps = [
+ "@pip//:numpy",
+ "@pip//:pandas",
+ ],
+)
+
+py_library(
+ name = "lib2",
+ srcs = ["lib2.py"],
+ visibility = ["//:__subpackages__"],
+ deps = [
+ ":lib",
+ ":lib_and_main",
+ ],
+)
+
+py_binary(
+ name = "lib_and_main",
+ srcs = ["lib_and_main.py"],
+ visibility = ["//:__subpackages__"],
+)
+
+py_binary(
+ name = "main",
+ srcs = ["main.py"],
+ visibility = ["//:__subpackages__"],
+ deps = ["@pip//:pandas"],
+)
+
+py_binary(
+ name = "main2",
+ srcs = ["main2.py"],
+ visibility = ["//:__subpackages__"],
+ deps = [":lib2"],
+)

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/README.md

@@ -0,0 +1,4 @@
+# Binary without entrypoint
+
+This test case asserts that when there is no __main__.py, a py_binary is generated per file main module, and that this
+py_binary is instead of (not in addition to) any py_library target.

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/WORKSPACE

@@ -0,0 +1 @@
+# This is a Bazel workspace for the Gazelle test data.

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/lib.py

@@ -0,0 +1,2 @@
+import numpy
+import pandas

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/lib2.py

@@ -0,0 +1,2 @@
+import lib
+import lib_and_main

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/lib_and_main.py

@@ -0,0 +1,6 @@
+def library_func():
+ print("library_func")
+
+
+if __name__ == "__main__":
+ library_func()

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/main.py

@@ -0,0 +1,4 @@
+import pandas
+
+if __name__ == "__main__":
+ run()

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/main2.py

@@ -0,0 +1,4 @@
+import lib2
+
+if __name__ == "__main__":
+ lib2.lib_and_main.library_func()

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/test.yaml

@@ -0,0 +1,17 @@
+# Copyright 2023 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+---
+expect:
+ exit_code: 0

CHANGELOG.md

@@ -40,6 +40,10 @@ A brief description of the categories of changes:
 * (toolchains) `py_runtime` can now take an executable target. Note: runfiles
  from the target are not supported yet.
 
+* (gazelle) When `python_generation_mode` is set to `file`, create one `py_binary`
+ target for each file with `if __name__ == "__main__"` instead of just one
+ `py_binary` for the whole module.
+
 ### Fixed
 
 * (gazelle) The gazelle plugin helper was not working with Python toolchains 3.11

gazelle/README.md

@@ -250,8 +250,20 @@ When no such entry point exists, Gazelle will look for a line like this in the t
 if __name == "__main__":
 ```
 
-Gazelle will create `py_binary` target will be created for every module with such line, with the target name
-being the same as module name.
+Gazelle will create a `py_binary` target for every module with such a line, with
+the target name the same as the module name.
+
+If `python_generation_mode` is set to `file`, then instead of one `py_binary`
+target per module, Gazelle will create one `py_binary` target for each file with
+such a line, and the name of the target will match the name of the script.
+
+Note that it's possible for another script to depend on a `py_binary` target and
+import from the `py_binary`'s scripts. This can have possible negative effects on
+Bazel analysis time and runfiles size compared to depending on a `py_library`
+target. The simplest way to avoid these negative effects is to extract library
+code into a separate script without a `main` line. Gazelle will then create a
+`py_library` target for that library code, and other scripts can depend on that
+`py_library` target.
 
 ## Developer Notes
 

gazelle/python/generate.go

@@ -225,23 +225,17 @@ func (py *Python) GenerateRules(args language.GenerateArgs) language.GenerateRes
  log.Fatalf("ERROR: %v\n", err)
  }
 
- // Check if a target with the same name we are generating already
- // exists, and if it is of a different kind from the one we are
- // generating. If so, we have to throw an error since Gazelle won't
- // generate it correctly.
- if err := ensureNoCollision(args.File, pyLibraryTargetName, actualPyLibraryKind); err != nil {
- fqTarget := label.New("", args.Rel, pyLibraryTargetName)
- err := fmt.Errorf("failed to generate target %q of kind %q: %w. "+
- "Use the '# gazelle:%s' directive to change the naming convention.",
- fqTarget.String(), actualPyLibraryKind, err, pythonconfig.LibraryNamingConvention)
- collisionErrors.Add(err)
- }
-
  if !hasPyBinaryEntryPointFile {
  // Creating one py_binary target per main module when __main__.py doesn't exist.
  mainFileNames := make([]string, 0, len(mainModules))
  for name := range mainModules {
  mainFileNames = append(mainFileNames, name)
+
+ // Remove the file from srcs if we're doing per-file library generation so
+ // that we don't also generate a py_library target for it.
+ if cfg.PerFileGeneration() {
+ srcs.Remove(name)
+ }
  }
  sort.Strings(mainFileNames)
  for _, filename := range mainFileNames {
@@ -262,6 +256,23 @@ func (py *Python) GenerateRules(args language.GenerateArgs) language.GenerateRes
  }
  }
 
+ // If we're doing per-file generation, srcs could be empty at this point, meaning we shouldn't make a py_library.
+ if srcs.Empty() {
+ return
+ }
+
+ // Check if a target with the same name we are generating already
+ // exists, and if it is of a different kind from the one we are
+ // generating. If so, we have to throw an error since Gazelle won't
+ // generate it correctly.
+ if err := ensureNoCollision(args.File, pyLibraryTargetName, actualPyLibraryKind); err != nil {
+ fqTarget := label.New("", args.Rel, pyLibraryTargetName)
+ err := fmt.Errorf("failed to generate target %q of kind %q: %w. "+
+ "Use the '# gazelle:%s' directive to change the naming convention.",
+ fqTarget.String(), actualPyLibraryKind, err, pythonconfig.LibraryNamingConvention)
+ collisionErrors.Add(err)
+ }
+
  pyLibrary := newTargetBuilder(pyLibraryKind, pyLibraryTargetName, pythonProjectRoot, args.Rel, pyFileNames).
  addVisibility(visibility).
  addSrcs(srcs).

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/BUILD.in

@@ -0,0 +1,4 @@
+# gazelle:python_generation_mode file
+
+# gazelle:resolve py numpy @pip//:numpy
+# gazelle:resolve py pandas @pip//:pandas

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/BUILD.out

@@ -0,0 +1,46 @@
+load("@rules_python//python:defs.bzl", "py_binary", "py_library")
+
+# gazelle:python_generation_mode file
+
+# gazelle:resolve py numpy @pip//:numpy
+# gazelle:resolve py pandas @pip//:pandas
+
+py_library(
+ name = "lib",
+ srcs = ["lib.py"],
+ visibility = ["//:__subpackages__"],
+ deps = [
+ "@pip//:numpy",
+ "@pip//:pandas",
+ ],
+)
+
+py_library(
+ name = "lib2",
+ srcs = ["lib2.py"],
+ visibility = ["//:__subpackages__"],
+ deps = [
+ ":lib",
+ ":lib_and_main",
+ ],
+)
+
+py_binary(
+ name = "lib_and_main",
+ srcs = ["lib_and_main.py"],
+ visibility = ["//:__subpackages__"],
+)
+
+py_binary(
+ name = "main",
+ srcs = ["main.py"],
+ visibility = ["//:__subpackages__"],
+ deps = ["@pip//:pandas"],
+)
+
+py_binary(
+ name = "main2",
+ srcs = ["main2.py"],
+ visibility = ["//:__subpackages__"],
+ deps = [":lib2"],
+)

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/README.md

@@ -0,0 +1,4 @@
+# Binary without entrypoint
+
+This test case asserts that when there is no __main__.py, a py_binary is generated per file main module, and that this
+py_binary is instead of (not in addition to) any py_library target.

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/WORKSPACE

@@ -0,0 +1 @@
+# This is a Bazel workspace for the Gazelle test data.

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/lib.py

@@ -0,0 +1,2 @@
+import numpy
+import pandas

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/lib2.py

@@ -0,0 +1,2 @@
+import lib
+import lib_and_main

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/lib_and_main.py

@@ -0,0 +1,6 @@
+def library_func():
+ print("library_func")
+
+
+if __name__ == "__main__":
+ library_func()

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/main.py

@@ -0,0 +1,4 @@
+import pandas
+
+if __name__ == "__main__":
+ run()

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/main2.py

@@ -0,0 +1,4 @@
+import lib2
+
+if __name__ == "__main__":
+ lib2.lib_and_main.library_func()

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/test.yaml

@@ -0,0 +1,17 @@
+# Copyright 2023 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+---
+expect:
+ exit_code: 0

CHANGELOG.md

@@ -40,6 +40,10 @@ A brief description of the categories of changes:
 * (toolchains) `py_runtime` can now take an executable target. Note: runfiles
  from the target are not supported yet.
 
+* (gazelle) When `python_generation_mode` is set to `file`, create one `py_binary`
+ target for each file with `if __name__ == "__main__"` instead of just one
+ `py_binary` for the whole module.
+
 ### Fixed
 
 * (gazelle) The gazelle plugin helper was not working with Python toolchains 3.11

gazelle/README.md

@@ -250,8 +250,20 @@ When no such entry point exists, Gazelle will look for a line like this in the t
 if __name == "__main__":
 ```
 
-Gazelle will create `py_binary` target will be created for every module with such line, with the target name
-being the same as module name.
+Gazelle will create a `py_binary` target for every module with such a line, with
+the target name the same as the module name.
+
+If `python_generation_mode` is set to `file`, then instead of one `py_binary`
+target per module, Gazelle will create one `py_binary` target for each file with
+such a line, and the name of the target will match the name of the script.
+
+Note that it's possible for another script to depend on a `py_binary` target and
+import from the `py_binary`'s scripts. This can have possible negative effects on
+Bazel analysis time and runfiles size compared to depending on a `py_library`
+target. The simplest way to avoid these negative effects is to extract library
+code into a separate script without a `main` line. Gazelle will then create a
+`py_library` target for that library code, and other scripts can depend on that
+`py_library` target.
 
 ## Developer Notes
 

gazelle/python/generate.go

@@ -225,23 +225,17 @@ func (py *Python) GenerateRules(args language.GenerateArgs) language.GenerateRes
  log.Fatalf("ERROR: %v\n", err)
  }
 
- // Check if a target with the same name we are generating already
- // exists, and if it is of a different kind from the one we are
- // generating. If so, we have to throw an error since Gazelle won't
- // generate it correctly.
- if err := ensureNoCollision(args.File, pyLibraryTargetName, actualPyLibraryKind); err != nil {
- fqTarget := label.New("", args.Rel, pyLibraryTargetName)
- err := fmt.Errorf("failed to generate target %q of kind %q: %w. "+
- "Use the '# gazelle:%s' directive to change the naming convention.",
- fqTarget.String(), actualPyLibraryKind, err, pythonconfig.LibraryNamingConvention)
- collisionErrors.Add(err)
- }
-
  if !hasPyBinaryEntryPointFile {
  // Creating one py_binary target per main module when __main__.py doesn't exist.
  mainFileNames := make([]string, 0, len(mainModules))
  for name := range mainModules {
  mainFileNames = append(mainFileNames, name)
+
+ // Remove the file from srcs if we're doing per-file library generation so
+ // that we don't also generate a py_library target for it.
+ if cfg.PerFileGeneration() {
+ srcs.Remove(name)
+ }
  }
  sort.Strings(mainFileNames)
  for _, filename := range mainFileNames {
@@ -262,6 +256,23 @@ func (py *Python) GenerateRules(args language.GenerateArgs) language.GenerateRes
  }
  }
 
+ // If we're doing per-file generation, srcs could be empty at this point, meaning we shouldn't make a py_library.
+ if srcs.Empty() {
+ return
+ }
+
+ // Check if a target with the same name we are generating already
+ // exists, and if it is of a different kind from the one we are
+ // generating. If so, we have to throw an error since Gazelle won't
+ // generate it correctly.
+ if err := ensureNoCollision(args.File, pyLibraryTargetName, actualPyLibraryKind); err != nil {
+ fqTarget := label.New("", args.Rel, pyLibraryTargetName)
+ err := fmt.Errorf("failed to generate target %q of kind %q: %w. "+
+ "Use the '# gazelle:%s' directive to change the naming convention.",
+ fqTarget.String(), actualPyLibraryKind, err, pythonconfig.LibraryNamingConvention)
+ collisionErrors.Add(err)
+ }
+
  pyLibrary := newTargetBuilder(pyLibraryKind, pyLibraryTargetName, pythonProjectRoot, args.Rel, pyFileNames).
  addVisibility(visibility).
  addSrcs(srcs).

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/BUILD.in

@@ -0,0 +1,4 @@
+# gazelle:python_generation_mode file
+
+# gazelle:resolve py numpy @pip//:numpy
+# gazelle:resolve py pandas @pip//:pandas

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/BUILD.out

@@ -0,0 +1,46 @@
+load("@rules_python//python:defs.bzl", "py_binary", "py_library")
+
+# gazelle:python_generation_mode file
+
+# gazelle:resolve py numpy @pip//:numpy
+# gazelle:resolve py pandas @pip//:pandas
+
+py_library(
+ name = "lib",
+ srcs = ["lib.py"],
+ visibility = ["//:__subpackages__"],
+ deps = [
+ "@pip//:numpy",
+ "@pip//:pandas",
+ ],
+)
+
+py_library(
+ name = "lib2",
+ srcs = ["lib2.py"],
+ visibility = ["//:__subpackages__"],
+ deps = [
+ ":lib",
+ ":lib_and_main",
+ ],
+)
+
+py_binary(
+ name = "lib_and_main",
+ srcs = ["lib_and_main.py"],
+ visibility = ["//:__subpackages__"],
+)
+
+py_binary(
+ name = "main",
+ srcs = ["main.py"],
+ visibility = ["//:__subpackages__"],
+ deps = ["@pip//:pandas"],
+)
+
+py_binary(
+ name = "main2",
+ srcs = ["main2.py"],
+ visibility = ["//:__subpackages__"],
+ deps = [":lib2"],
+)

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/README.md

@@ -0,0 +1,4 @@
+# Binary without entrypoint
+
+This test case asserts that when there is no __main__.py, a py_binary is generated per file main module, and that this
+py_binary is instead of (not in addition to) any py_library target.

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/WORKSPACE

@@ -0,0 +1 @@
+# This is a Bazel workspace for the Gazelle test data.

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/lib.py

@@ -0,0 +1,2 @@
+import numpy
+import pandas

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/lib2.py

@@ -0,0 +1,2 @@
+import lib
+import lib_and_main

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/lib_and_main.py

@@ -0,0 +1,6 @@
+def library_func():
+ print("library_func")
+
+
+if __name__ == "__main__":
+ library_func()

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/main.py

@@ -0,0 +1,4 @@
+import pandas
+
+if __name__ == "__main__":
+ run()

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/main2.py

@@ -0,0 +1,4 @@
+import lib2
+
+if __name__ == "__main__":
+ lib2.lib_and_main.library_func()

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/test.yaml

@@ -0,0 +1,17 @@
+# Copyright 2023 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+---
+expect:
+ exit_code: 0

CHANGELOG.md

@@ -40,6 +40,10 @@ A brief description of the categories of changes:
 * (toolchains) `py_runtime` can now take an executable target. Note: runfiles
  from the target are not supported yet.
 
+* (gazelle) When `python_generation_mode` is set to `file`, create one `py_binary`
+ target for each file with `if __name__ == "__main__"` instead of just one
+ `py_binary` for the whole module.
+
 ### Fixed
 
 * (gazelle) The gazelle plugin helper was not working with Python toolchains 3.11

gazelle/README.md

@@ -250,8 +250,20 @@ When no such entry point exists, Gazelle will look for a line like this in the t
 if __name == "__main__":
 ```
 
-Gazelle will create `py_binary` target will be created for every module with such line, with the target name
-being the same as module name.
+Gazelle will create a `py_binary` target for every module with such a line, with
+the target name the same as the module name.
+
+If `python_generation_mode` is set to `file`, then instead of one `py_binary`
+target per module, Gazelle will create one `py_binary` target for each file with
+such a line, and the name of the target will match the name of the script.
+
+Note that it's possible for another script to depend on a `py_binary` target and
+import from the `py_binary`'s scripts. This can have possible negative effects on
+Bazel analysis time and runfiles size compared to depending on a `py_library`
+target. The simplest way to avoid these negative effects is to extract library
+code into a separate script without a `main` line. Gazelle will then create a
+`py_library` target for that library code, and other scripts can depend on that
+`py_library` target.
 
 ## Developer Notes
 

gazelle/python/generate.go

@@ -225,23 +225,17 @@ func (py *Python) GenerateRules(args language.GenerateArgs) language.GenerateRes
  log.Fatalf("ERROR: %v\n", err)
  }
 
- // Check if a target with the same name we are generating already
- // exists, and if it is of a different kind from the one we are
- // generating. If so, we have to throw an error since Gazelle won't
- // generate it correctly.
- if err := ensureNoCollision(args.File, pyLibraryTargetName, actualPyLibraryKind); err != nil {
- fqTarget := label.New("", args.Rel, pyLibraryTargetName)
- err := fmt.Errorf("failed to generate target %q of kind %q: %w. "+
- "Use the '# gazelle:%s' directive to change the naming convention.",
- fqTarget.String(), actualPyLibraryKind, err, pythonconfig.LibraryNamingConvention)
- collisionErrors.Add(err)
- }
-
  if !hasPyBinaryEntryPointFile {
  // Creating one py_binary target per main module when __main__.py doesn't exist.
  mainFileNames := make([]string, 0, len(mainModules))
  for name := range mainModules {
  mainFileNames = append(mainFileNames, name)
+
+ // Remove the file from srcs if we're doing per-file library generation so
+ // that we don't also generate a py_library target for it.
+ if cfg.PerFileGeneration() {
+ srcs.Remove(name)
+ }
  }
  sort.Strings(mainFileNames)
  for _, filename := range mainFileNames {
@@ -262,6 +256,23 @@ func (py *Python) GenerateRules(args language.GenerateArgs) language.GenerateRes
  }
  }
 
+ // If we're doing per-file generation, srcs could be empty at this point, meaning we shouldn't make a py_library.
+ if srcs.Empty() {
+ return
+ }
+
+ // Check if a target with the same name we are generating already
+ // exists, and if it is of a different kind from the one we are
+ // generating. If so, we have to throw an error since Gazelle won't
+ // generate it correctly.
+ if err := ensureNoCollision(args.File, pyLibraryTargetName, actualPyLibraryKind); err != nil {
+ fqTarget := label.New("", args.Rel, pyLibraryTargetName)
+ err := fmt.Errorf("failed to generate target %q of kind %q: %w. "+
+ "Use the '# gazelle:%s' directive to change the naming convention.",
+ fqTarget.String(), actualPyLibraryKind, err, pythonconfig.LibraryNamingConvention)
+ collisionErrors.Add(err)
+ }
+
  pyLibrary := newTargetBuilder(pyLibraryKind, pyLibraryTargetName, pythonProjectRoot, args.Rel, pyFileNames).
  addVisibility(visibility).
  addSrcs(srcs).

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/BUILD.in

@@ -0,0 +1,4 @@
+# gazelle:python_generation_mode file
+
+# gazelle:resolve py numpy @pip//:numpy
+# gazelle:resolve py pandas @pip//:pandas

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/BUILD.out

@@ -0,0 +1,46 @@
+load("@rules_python//python:defs.bzl", "py_binary", "py_library")
+
+# gazelle:python_generation_mode file
+
+# gazelle:resolve py numpy @pip//:numpy
+# gazelle:resolve py pandas @pip//:pandas
+
+py_library(
+ name = "lib",
+ srcs = ["lib.py"],
+ visibility = ["//:__subpackages__"],
+ deps = [
+ "@pip//:numpy",
+ "@pip//:pandas",
+ ],
+)
+
+py_library(
+ name = "lib2",
+ srcs = ["lib2.py"],
+ visibility = ["//:__subpackages__"],
+ deps = [
+ ":lib",
+ ":lib_and_main",
+ ],
+)
+
+py_binary(
+ name = "lib_and_main",
+ srcs = ["lib_and_main.py"],
+ visibility = ["//:__subpackages__"],
+)
+
+py_binary(
+ name = "main",
+ srcs = ["main.py"],
+ visibility = ["//:__subpackages__"],
+ deps = ["@pip//:pandas"],
+)
+
+py_binary(
+ name = "main2",
+ srcs = ["main2.py"],
+ visibility = ["//:__subpackages__"],
+ deps = [":lib2"],
+)

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/README.md

@@ -0,0 +1,4 @@
+# Binary without entrypoint
+
+This test case asserts that when there is no __main__.py, a py_binary is generated per file main module, and that this
+py_binary is instead of (not in addition to) any py_library target.

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/WORKSPACE

@@ -0,0 +1 @@
+# This is a Bazel workspace for the Gazelle test data.

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/lib.py

@@ -0,0 +1,2 @@
+import numpy
+import pandas

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/lib2.py

@@ -0,0 +1,2 @@
+import lib
+import lib_and_main

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/lib_and_main.py

@@ -0,0 +1,6 @@
+def library_func():
+ print("library_func")
+
+
+if __name__ == "__main__":
+ library_func()

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/main.py

@@ -0,0 +1,4 @@
+import pandas
+
+if __name__ == "__main__":
+ run()

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/main2.py

@@ -0,0 +1,4 @@
+import lib2
+
+if __name__ == "__main__":
+ lib2.lib_and_main.library_func()

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/test.yaml

@@ -0,0 +1,17 @@
+# Copyright 2023 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+---
+expect:
+ exit_code: 0

CHANGELOG.md

@@ -40,6 +40,10 @@ A brief description of the categories of changes:
 * (toolchains) `py_runtime` can now take an executable target. Note: runfiles
  from the target are not supported yet.
 
+* (gazelle) When `python_generation_mode` is set to `file`, create one `py_binary`
+ target for each file with `if __name__ == "__main__"` instead of just one
+ `py_binary` for the whole module.
+
 ### Fixed
 
 * (gazelle) The gazelle plugin helper was not working with Python toolchains 3.11

gazelle/README.md

@@ -250,8 +250,20 @@ When no such entry point exists, Gazelle will look for a line like this in the t
 if __name == "__main__":
 ```
 
-Gazelle will create `py_binary` target will be created for every module with such line, with the target name
-being the same as module name.
+Gazelle will create a `py_binary` target for every module with such a line, with
+the target name the same as the module name.
+
+If `python_generation_mode` is set to `file`, then instead of one `py_binary`
+target per module, Gazelle will create one `py_binary` target for each file with
+such a line, and the name of the target will match the name of the script.
+
+Note that it's possible for another script to depend on a `py_binary` target and
+import from the `py_binary`'s scripts. This can have possible negative effects on
+Bazel analysis time and runfiles size compared to depending on a `py_library`
+target. The simplest way to avoid these negative effects is to extract library
+code into a separate script without a `main` line. Gazelle will then create a
+`py_library` target for that library code, and other scripts can depend on that
+`py_library` target.
 
 ## Developer Notes
 

gazelle/python/generate.go

@@ -225,23 +225,17 @@ func (py *Python) GenerateRules(args language.GenerateArgs) language.GenerateRes
  log.Fatalf("ERROR: %v\n", err)
  }
 
- // Check if a target with the same name we are generating already
- // exists, and if it is of a different kind from the one we are
- // generating. If so, we have to throw an error since Gazelle won't
- // generate it correctly.
- if err := ensureNoCollision(args.File, pyLibraryTargetName, actualPyLibraryKind); err != nil {
- fqTarget := label.New("", args.Rel, pyLibraryTargetName)
- err := fmt.Errorf("failed to generate target %q of kind %q: %w. "+
- "Use the '# gazelle:%s' directive to change the naming convention.",
- fqTarget.String(), actualPyLibraryKind, err, pythonconfig.LibraryNamingConvention)
- collisionErrors.Add(err)
- }
-
  if !hasPyBinaryEntryPointFile {
  // Creating one py_binary target per main module when __main__.py doesn't exist.
  mainFileNames := make([]string, 0, len(mainModules))
  for name := range mainModules {
  mainFileNames = append(mainFileNames, name)
+
+ // Remove the file from srcs if we're doing per-file library generation so
+ // that we don't also generate a py_library target for it.
+ if cfg.PerFileGeneration() {
+ srcs.Remove(name)
+ }
  }
  sort.Strings(mainFileNames)
  for _, filename := range mainFileNames {
@@ -262,6 +256,23 @@ func (py *Python) GenerateRules(args language.GenerateArgs) language.GenerateRes
  }
  }
 
+ // If we're doing per-file generation, srcs could be empty at this point, meaning we shouldn't make a py_library.
+ if srcs.Empty() {
+ return
+ }
+
+ // Check if a target with the same name we are generating already
+ // exists, and if it is of a different kind from the one we are
+ // generating. If so, we have to throw an error since Gazelle won't
+ // generate it correctly.
+ if err := ensureNoCollision(args.File, pyLibraryTargetName, actualPyLibraryKind); err != nil {
+ fqTarget := label.New("", args.Rel, pyLibraryTargetName)
+ err := fmt.Errorf("failed to generate target %q of kind %q: %w. "+
+ "Use the '# gazelle:%s' directive to change the naming convention.",
+ fqTarget.String(), actualPyLibraryKind, err, pythonconfig.LibraryNamingConvention)
+ collisionErrors.Add(err)
+ }
+
  pyLibrary := newTargetBuilder(pyLibraryKind, pyLibraryTargetName, pythonProjectRoot, args.Rel, pyFileNames).
  addVisibility(visibility).
  addSrcs(srcs).

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/BUILD.in

@@ -0,0 +1,4 @@
+# gazelle:python_generation_mode file
+
+# gazelle:resolve py numpy @pip//:numpy
+# gazelle:resolve py pandas @pip//:pandas

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/BUILD.out

@@ -0,0 +1,46 @@
+load("@rules_python//python:defs.bzl", "py_binary", "py_library")
+
+# gazelle:python_generation_mode file
+
+# gazelle:resolve py numpy @pip//:numpy
+# gazelle:resolve py pandas @pip//:pandas
+
+py_library(
+ name = "lib",
+ srcs = ["lib.py"],
+ visibility = ["//:__subpackages__"],
+ deps = [
+ "@pip//:numpy",
+ "@pip//:pandas",
+ ],
+)
+
+py_library(
+ name = "lib2",
+ srcs = ["lib2.py"],
+ visibility = ["//:__subpackages__"],
+ deps = [
+ ":lib",
+ ":lib_and_main",
+ ],
+)
+
+py_binary(
+ name = "lib_and_main",
+ srcs = ["lib_and_main.py"],
+ visibility = ["//:__subpackages__"],
+)
+
+py_binary(
+ name = "main",
+ srcs = ["main.py"],
+ visibility = ["//:__subpackages__"],
+ deps = ["@pip//:pandas"],
+)
+
+py_binary(
+ name = "main2",
+ srcs = ["main2.py"],
+ visibility = ["//:__subpackages__"],
+ deps = [":lib2"],
+)

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/README.md

@@ -0,0 +1,4 @@
+# Binary without entrypoint
+
+This test case asserts that when there is no __main__.py, a py_binary is generated per file main module, and that this
+py_binary is instead of (not in addition to) any py_library target.

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/WORKSPACE

@@ -0,0 +1 @@
+# This is a Bazel workspace for the Gazelle test data.

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/lib.py

@@ -0,0 +1,2 @@
+import numpy
+import pandas

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/lib2.py

@@ -0,0 +1,2 @@
+import lib
+import lib_and_main

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/lib_and_main.py

@@ -0,0 +1,6 @@
+def library_func():
+ print("library_func")
+
+
+if __name__ == "__main__":
+ library_func()

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/main.py

@@ -0,0 +1,4 @@
+import pandas
+
+if __name__ == "__main__":
+ run()

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/main2.py

@@ -0,0 +1,4 @@
+import lib2
+
+if __name__ == "__main__":
+ lib2.lib_and_main.library_func()

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/test.yaml

@@ -0,0 +1,17 @@
+# Copyright 2023 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+---
+expect:
+ exit_code: 0

CHANGELOG.md

@@ -40,6 +40,10 @@ A brief description of the categories of changes:
 * (toolchains) `py_runtime` can now take an executable target. Note: runfiles
  from the target are not supported yet.
 
+* (gazelle) When `python_generation_mode` is set to `file`, create one `py_binary`
+ target for each file with `if __name__ == "__main__"` instead of just one
+ `py_binary` for the whole module.
+
 ### Fixed
 
 * (gazelle) The gazelle plugin helper was not working with Python toolchains 3.11

gazelle/README.md

@@ -250,8 +250,20 @@ When no such entry point exists, Gazelle will look for a line like this in the t
 if __name == "__main__":
 ```
 
-Gazelle will create `py_binary` target will be created for every module with such line, with the target name
-being the same as module name.
+Gazelle will create a `py_binary` target for every module with such a line, with
+the target name the same as the module name.
+
+If `python_generation_mode` is set to `file`, then instead of one `py_binary`
+target per module, Gazelle will create one `py_binary` target for each file with
+such a line, and the name of the target will match the name of the script.
+
+Note that it's possible for another script to depend on a `py_binary` target and
+import from the `py_binary`'s scripts. This can have possible negative effects on
+Bazel analysis time and runfiles size compared to depending on a `py_library`
+target. The simplest way to avoid these negative effects is to extract library
+code into a separate script without a `main` line. Gazelle will then create a
+`py_library` target for that library code, and other scripts can depend on that
+`py_library` target.
 
 ## Developer Notes
 

gazelle/python/generate.go

@@ -225,23 +225,17 @@ func (py *Python) GenerateRules(args language.GenerateArgs) language.GenerateRes
  log.Fatalf("ERROR: %v\n", err)
  }
 
- // Check if a target with the same name we are generating already
- // exists, and if it is of a different kind from the one we are
- // generating. If so, we have to throw an error since Gazelle won't
- // generate it correctly.
- if err := ensureNoCollision(args.File, pyLibraryTargetName, actualPyLibraryKind); err != nil {
- fqTarget := label.New("", args.Rel, pyLibraryTargetName)
- err := fmt.Errorf("failed to generate target %q of kind %q: %w. "+
- "Use the '# gazelle:%s' directive to change the naming convention.",
- fqTarget.String(), actualPyLibraryKind, err, pythonconfig.LibraryNamingConvention)
- collisionErrors.Add(err)
- }
-
  if !hasPyBinaryEntryPointFile {
  // Creating one py_binary target per main module when __main__.py doesn't exist.
  mainFileNames := make([]string, 0, len(mainModules))
  for name := range mainModules {
  mainFileNames = append(mainFileNames, name)
+
+ // Remove the file from srcs if we're doing per-file library generation so
+ // that we don't also generate a py_library target for it.
+ if cfg.PerFileGeneration() {
+ srcs.Remove(name)
+ }
  }
  sort.Strings(mainFileNames)
  for _, filename := range mainFileNames {
@@ -262,6 +256,23 @@ func (py *Python) GenerateRules(args language.GenerateArgs) language.GenerateRes
  }
  }
 
+ // If we're doing per-file generation, srcs could be empty at this point, meaning we shouldn't make a py_library.
+ if srcs.Empty() {
+ return
+ }
+
+ // Check if a target with the same name we are generating already
+ // exists, and if it is of a different kind from the one we are
+ // generating. If so, we have to throw an error since Gazelle won't
+ // generate it correctly.
+ if err := ensureNoCollision(args.File, pyLibraryTargetName, actualPyLibraryKind); err != nil {
+ fqTarget := label.New("", args.Rel, pyLibraryTargetName)
+ err := fmt.Errorf("failed to generate target %q of kind %q: %w. "+
+ "Use the '# gazelle:%s' directive to change the naming convention.",
+ fqTarget.String(), actualPyLibraryKind, err, pythonconfig.LibraryNamingConvention)
+ collisionErrors.Add(err)
+ }
+
  pyLibrary := newTargetBuilder(pyLibraryKind, pyLibraryTargetName, pythonProjectRoot, args.Rel, pyFileNames).
  addVisibility(visibility).
  addSrcs(srcs).

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/BUILD.in

@@ -0,0 +1,4 @@
+# gazelle:python_generation_mode file
+
+# gazelle:resolve py numpy @pip//:numpy
+# gazelle:resolve py pandas @pip//:pandas

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/BUILD.out

@@ -0,0 +1,46 @@
+load("@rules_python//python:defs.bzl", "py_binary", "py_library")
+
+# gazelle:python_generation_mode file
+
+# gazelle:resolve py numpy @pip//:numpy
+# gazelle:resolve py pandas @pip//:pandas
+
+py_library(
+ name = "lib",
+ srcs = ["lib.py"],
+ visibility = ["//:__subpackages__"],
+ deps = [
+ "@pip//:numpy",
+ "@pip//:pandas",
+ ],
+)
+
+py_library(
+ name = "lib2",
+ srcs = ["lib2.py"],
+ visibility = ["//:__subpackages__"],
+ deps = [
+ ":lib",
+ ":lib_and_main",
+ ],
+)
+
+py_binary(
+ name = "lib_and_main",
+ srcs = ["lib_and_main.py"],
+ visibility = ["//:__subpackages__"],
+)
+
+py_binary(
+ name = "main",
+ srcs = ["main.py"],
+ visibility = ["//:__subpackages__"],
+ deps = ["@pip//:pandas"],
+)
+
+py_binary(
+ name = "main2",
+ srcs = ["main2.py"],
+ visibility = ["//:__subpackages__"],
+ deps = [":lib2"],
+)

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/README.md

@@ -0,0 +1,4 @@
+# Binary without entrypoint
+
+This test case asserts that when there is no __main__.py, a py_binary is generated per file main module, and that this
+py_binary is instead of (not in addition to) any py_library target.

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/WORKSPACE

@@ -0,0 +1 @@
+# This is a Bazel workspace for the Gazelle test data.

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/lib.py

@@ -0,0 +1,2 @@
+import numpy
+import pandas

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/lib2.py

@@ -0,0 +1,2 @@
+import lib
+import lib_and_main

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/lib_and_main.py

@@ -0,0 +1,6 @@
+def library_func():
+ print("library_func")
+
+
+if __name__ == "__main__":
+ library_func()

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/main.py

@@ -0,0 +1,4 @@
+import pandas
+
+if __name__ == "__main__":
+ run()

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/main2.py

@@ -0,0 +1,4 @@
+import lib2
+
+if __name__ == "__main__":
+ lib2.lib_and_main.library_func()

gazelle/python/testdata/binary_without_entrypoint_per_file_generation/test.yaml

@@ -0,0 +1,17 @@
+# Copyright 2023 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+---
+expect:
+ exit_code: 0