Panic surface: unreachable!() clusters and mutex-poison cascade #116

Closed
#240
Closed
Panic surface: unreachable!() clusters and mutex-poison cascade#116
#240
Labels
bugSomething isn't working

Description

@Tryanks
Tryanks
opened on Jul 19, 2026

Status — partially changed, still open (reviewed 2026-08-22)

The terminal was split into PTY and grid components, the big chat.rs was split into chat/mod.rs + chat/model.rs + components, and several unrelated crash paths were hardened — but the invariant/panic sweep itself is not complete.

Current evidence on main (e8a5f1cc)

  1. Invariant aborts

    • 8 production unreachable!() sites remain (test-module sites excluded): 5 in crates/ui/src/chat/mod.rs (302, 313, 375, 513, 778), plus crates/ui/src/chat/components/subagent.rs:39, crates/core/src/session.rs:1095, and crates/runtime/src/app/orchestrate.rs:931.
    • The earlier crates/agent/src/acp.rsunreachable!() cluster is gone, and the count is down from 13; the remaining sites still turn presentation- and session-state assumptions into process aborts.

  2. Mutex poisoning

    • std::sync::Mutex with lock().unwrap() remains widespread: crates/agent/src/acp.rs (37 call sites), crates/term/src/grid_emulator.rs (9), crates/term/src/pty.rs (5), crates/term/src/pty_info.rs (1).
    • A panic while holding any of these shared locks can cascade into later UI/reader-thread panics.

  3. Child-pipe assumptions

    • ACP launch still uses expect("piped stdin/stdout/stderr") after spawning the agent (crates/agent/src/acp.rs:327-329), and ACP terminal creation has the same stdout/stderr assumptions (acp.rs:2423-2424).
    • These should surface structured start/terminal errors rather than aborting.

Direction

  • Replace externally reachable unreachable!() branches with logged fallback/error events; keep debug_assert! for developer visibility.
  • Use non-poisoning mutexes where appropriate, or recover poison explicitly when continuing is safe.
  • Convert child-pipe expect calls and counter-overflow expects into propagated errors.
  • Add targeted tests that inject unexpected variants, poisoned locks, and missing child pipes.

Acceptance criteria

No provider output, recoverable process-launch failure, or terminal worker panic can abort the application solely through these clusters.

Effort: M · Risk: LOW–MED

Metadata

Metadata

Assignees

No one assigned

    Labels

    bugSomething isn't working

    Projects

    No projects

      Milestone

      No milestone

      Relationships

      None yet

      Development

      No branches or pull requests

      Issue actions

      , 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
       blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

      Skip to content
      Panic surface: unreachable!() clusters and mutex-poison cascade #116
      Closed
      #240
      Closed
      Panic surface: unreachable!() clusters and mutex-poison cascade#116
      #240
      Labels
      bugSomething isn't working
      Description
      @Tryanks
      Tryanks
      opened on Jul 19, 2026
      Status — partially changed, still open (reviewed 2026-08-22)
      The terminal was split into PTY and grid components, the big chat.rs was split into chat/mod.rs + chat/model.rs + components, and several unrelated crash paths were hardened — but the invariant/panic sweep itself is not complete.
      Current evidence on main (e8a5f1cc)
      1. Invariant aborts
        • 8 production unreachable!() sites remain (test-module sites excluded): 5 in crates/ui/src/chat/mod.rs (302, 313, 375, 513, 778), plus crates/ui/src/chat/components/subagent.rs:39, crates/core/src/session.rs:1095, and crates/runtime/src/app/orchestrate.rs:931.
        • The earlier crates/agent/src/acp.rsunreachable!() cluster is gone, and the count is down from 13; the remaining sites still turn presentation- and session-state assumptions into process aborts.
      2. Mutex poisoning
        • std::sync::Mutex with lock().unwrap() remains widespread: crates/agent/src/acp.rs (37 call sites), crates/term/src/grid_emulator.rs (9), crates/term/src/pty.rs (5), crates/term/src/pty_info.rs (1).
        • A panic while holding any of these shared locks can cascade into later UI/reader-thread panics.
      3. Child-pipe assumptions
        • ACP launch still uses expect("piped stdin/stdout/stderr") after spawning the agent (crates/agent/src/acp.rs:327-329), and ACP terminal creation has the same stdout/stderr assumptions (acp.rs:2423-2424).
        • These should surface structured start/terminal errors rather than aborting.
      Direction
      • Replace externally reachable unreachable!() branches with logged fallback/error events; keep debug_assert! for developer visibility.
      • Use non-poisoning mutexes where appropriate, or recover poison explicitly when continuing is safe.
      • Convert child-pipe expect calls and counter-overflow expects into propagated errors.
      • Add targeted tests that inject unexpected variants, poisoned locks, and missing child pipes.
      Acceptance criteria
      No provider output, recoverable process-launch failure, or terminal worker panic can abort the application solely through these clusters.
      Effort: M · Risk: LOW–MED
      Metadata
      Metadata
      Assignees
      No one assigned
        Labels
        bugSomething isn't working
        Projects
        No projects
          Milestone
          No milestone
          Relationships
          None yet
          Development
          No branches or pull requests
          Issue actions
          
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

          Skip to content
          Panic surface: unreachable!() clusters and mutex-poison cascade #116
          Closed
          #240
          Closed
          Panic surface: unreachable!() clusters and mutex-poison cascade#116
          #240
          Labels
          bugSomething isn't working
          Description
          @Tryanks
          Tryanks
          opened on Jul 19, 2026
          Status — partially changed, still open (reviewed 2026-08-22)
          The terminal was split into PTY and grid components, the big chat.rs was split into chat/mod.rs + chat/model.rs + components, and several unrelated crash paths were hardened — but the invariant/panic sweep itself is not complete.
          Current evidence on main (e8a5f1cc)
          1. Invariant aborts
            • 8 production unreachable!() sites remain (test-module sites excluded): 5 in crates/ui/src/chat/mod.rs (302, 313, 375, 513, 778), plus crates/ui/src/chat/components/subagent.rs:39, crates/core/src/session.rs:1095, and crates/runtime/src/app/orchestrate.rs:931.
            • The earlier crates/agent/src/acp.rsunreachable!() cluster is gone, and the count is down from 13; the remaining sites still turn presentation- and session-state assumptions into process aborts.
          2. Mutex poisoning
            • std::sync::Mutex with lock().unwrap() remains widespread: crates/agent/src/acp.rs (37 call sites), crates/term/src/grid_emulator.rs (9), crates/term/src/pty.rs (5), crates/term/src/pty_info.rs (1).
            • A panic while holding any of these shared locks can cascade into later UI/reader-thread panics.
          3. Child-pipe assumptions
            • ACP launch still uses expect("piped stdin/stdout/stderr") after spawning the agent (crates/agent/src/acp.rs:327-329), and ACP terminal creation has the same stdout/stderr assumptions (acp.rs:2423-2424).
            • These should surface structured start/terminal errors rather than aborting.
          Direction
          • Replace externally reachable unreachable!() branches with logged fallback/error events; keep debug_assert! for developer visibility.
          • Use non-poisoning mutexes where appropriate, or recover poison explicitly when continuing is safe.
          • Convert child-pipe expect calls and counter-overflow expects into propagated errors.
          • Add targeted tests that inject unexpected variants, poisoned locks, and missing child pipes.
          Acceptance criteria
          No provider output, recoverable process-launch failure, or terminal worker panic can abort the application solely through these clusters.
          Effort: M · Risk: LOW–MED
          Metadata
          Metadata
          Assignees
          No one assigned
            Labels
            bugSomething isn't working
            Projects
            No projects
              Milestone
              No milestone
              Relationships
              None yet
              Development
              No branches or pull requests
              Issue actions
              
, '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('^' + ".*" + '

              Skip to content
              Panic surface: unreachable!() clusters and mutex-poison cascade #116
              Closed
              #240
              Closed
              Panic surface: unreachable!() clusters and mutex-poison cascade#116
              #240
              Labels
              bugSomething isn't working
              Description
              @Tryanks
              Tryanks
              opened on Jul 19, 2026
              Status — partially changed, still open (reviewed 2026-08-22)
              The terminal was split into PTY and grid components, the big chat.rs was split into chat/mod.rs + chat/model.rs + components, and several unrelated crash paths were hardened — but the invariant/panic sweep itself is not complete.
              Current evidence on main (e8a5f1cc)
              1. Invariant aborts
                • 8 production unreachable!() sites remain (test-module sites excluded): 5 in crates/ui/src/chat/mod.rs (302, 313, 375, 513, 778), plus crates/ui/src/chat/components/subagent.rs:39, crates/core/src/session.rs:1095, and crates/runtime/src/app/orchestrate.rs:931.
                • The earlier crates/agent/src/acp.rsunreachable!() cluster is gone, and the count is down from 13; the remaining sites still turn presentation- and session-state assumptions into process aborts.
              2. Mutex poisoning
                • std::sync::Mutex with lock().unwrap() remains widespread: crates/agent/src/acp.rs (37 call sites), crates/term/src/grid_emulator.rs (9), crates/term/src/pty.rs (5), crates/term/src/pty_info.rs (1).
                • A panic while holding any of these shared locks can cascade into later UI/reader-thread panics.
              3. Child-pipe assumptions
                • ACP launch still uses expect("piped stdin/stdout/stderr") after spawning the agent (crates/agent/src/acp.rs:327-329), and ACP terminal creation has the same stdout/stderr assumptions (acp.rs:2423-2424).
                • These should surface structured start/terminal errors rather than aborting.
              Direction
              • Replace externally reachable unreachable!() branches with logged fallback/error events; keep debug_assert! for developer visibility.
              • Use non-poisoning mutexes where appropriate, or recover poison explicitly when continuing is safe.
              • Convert child-pipe expect calls and counter-overflow expects into propagated errors.
              • Add targeted tests that inject unexpected variants, poisoned locks, and missing child pipes.
              Acceptance criteria
              No provider output, recoverable process-launch failure, or terminal worker panic can abort the application solely through these clusters.
              Effort: M · Risk: LOW–MED
              Metadata
              Metadata
              Assignees
              No one assigned
                Labels
                bugSomething isn't working
                Projects
                No projects
                  Milestone
                  No milestone
                  Relationships
                  None yet
                  Development
                  No branches or pull requests
                  Issue actions
                  
, '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" + '

                  Skip to content
                  Panic surface: unreachable!() clusters and mutex-poison cascade #116
                  Closed
                  #240
                  Closed
                  Panic surface: unreachable!() clusters and mutex-poison cascade#116
                  #240
                  Labels
                  bugSomething isn't working
                  Description
                  @Tryanks
                  Tryanks
                  opened on Jul 19, 2026
                  Status — partially changed, still open (reviewed 2026-08-22)
                  The terminal was split into PTY and grid components, the big chat.rs was split into chat/mod.rs + chat/model.rs + components, and several unrelated crash paths were hardened — but the invariant/panic sweep itself is not complete.
                  Current evidence on main (e8a5f1cc)
                  1. Invariant aborts
                    • 8 production unreachable!() sites remain (test-module sites excluded): 5 in crates/ui/src/chat/mod.rs (302, 313, 375, 513, 778), plus crates/ui/src/chat/components/subagent.rs:39, crates/core/src/session.rs:1095, and crates/runtime/src/app/orchestrate.rs:931.
                    • The earlier crates/agent/src/acp.rsunreachable!() cluster is gone, and the count is down from 13; the remaining sites still turn presentation- and session-state assumptions into process aborts.
                  2. Mutex poisoning
                    • std::sync::Mutex with lock().unwrap() remains widespread: crates/agent/src/acp.rs (37 call sites), crates/term/src/grid_emulator.rs (9), crates/term/src/pty.rs (5), crates/term/src/pty_info.rs (1).
                    • A panic while holding any of these shared locks can cascade into later UI/reader-thread panics.
                  3. Child-pipe assumptions
                    • ACP launch still uses expect("piped stdin/stdout/stderr") after spawning the agent (crates/agent/src/acp.rs:327-329), and ACP terminal creation has the same stdout/stderr assumptions (acp.rs:2423-2424).
                    • These should surface structured start/terminal errors rather than aborting.
                  Direction
                  • Replace externally reachable unreachable!() branches with logged fallback/error events; keep debug_assert! for developer visibility.
                  • Use non-poisoning mutexes where appropriate, or recover poison explicitly when continuing is safe.
                  • Convert child-pipe expect calls and counter-overflow expects into propagated errors.
                  • Add targeted tests that inject unexpected variants, poisoned locks, and missing child pipes.
                  Acceptance criteria
                  No provider output, recoverable process-launch failure, or terminal worker panic can abort the application solely through these clusters.
                  Effort: M · Risk: LOW–MED
                  Metadata
                  Metadata
                  Assignees
                  No one assigned
                    Labels
                    bugSomething isn't working
                    Projects
                    No projects
                      Milestone
                      No milestone
                      Relationships
                      None yet
                      Development
                      No branches or pull requests
                      Issue actions
                      
, '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
                      Panic surface: unreachable!() clusters and mutex-poison cascade #116
                      Closed
                      #240
                      Closed
                      Panic surface: unreachable!() clusters and mutex-poison cascade#116
                      #240
                      Labels
                      bugSomething isn't working
                      Description
                      @Tryanks
                      Tryanks
                      opened on Jul 19, 2026
                      Status — partially changed, still open (reviewed 2026-08-22)
                      The terminal was split into PTY and grid components, the big chat.rs was split into chat/mod.rs + chat/model.rs + components, and several unrelated crash paths were hardened — but the invariant/panic sweep itself is not complete.
                      Current evidence on main (e8a5f1cc)
                      1. Invariant aborts
                        • 8 production unreachable!() sites remain (test-module sites excluded): 5 in crates/ui/src/chat/mod.rs (302, 313, 375, 513, 778), plus crates/ui/src/chat/components/subagent.rs:39, crates/core/src/session.rs:1095, and crates/runtime/src/app/orchestrate.rs:931.
                        • The earlier crates/agent/src/acp.rsunreachable!() cluster is gone, and the count is down from 13; the remaining sites still turn presentation- and session-state assumptions into process aborts.
                      2. Mutex poisoning
                        • std::sync::Mutex with lock().unwrap() remains widespread: crates/agent/src/acp.rs (37 call sites), crates/term/src/grid_emulator.rs (9), crates/term/src/pty.rs (5), crates/term/src/pty_info.rs (1).
                        • A panic while holding any of these shared locks can cascade into later UI/reader-thread panics.
                      3. Child-pipe assumptions
                        • ACP launch still uses expect("piped stdin/stdout/stderr") after spawning the agent (crates/agent/src/acp.rs:327-329), and ACP terminal creation has the same stdout/stderr assumptions (acp.rs:2423-2424).
                        • These should surface structured start/terminal errors rather than aborting.
                      Direction
                      • Replace externally reachable unreachable!() branches with logged fallback/error events; keep debug_assert! for developer visibility.
                      • Use non-poisoning mutexes where appropriate, or recover poison explicitly when continuing is safe.
                      • Convert child-pipe expect calls and counter-overflow expects into propagated errors.
                      • Add targeted tests that inject unexpected variants, poisoned locks, and missing child pipes.
                      Acceptance criteria
                      No provider output, recoverable process-launch failure, or terminal worker panic can abort the application solely through these clusters.
                      Effort: M · Risk: LOW–MED
                      Metadata
                      Metadata
                      Assignees
                      No one assigned
                        Labels
                        bugSomething isn't working
                        Projects
                        No projects
                          Milestone
                          No milestone
                          Relationships
                          None yet
                          Development
                          No branches or pull requests
                          Issue actions
                          
, '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('^' + ".*" + '

                          Skip to content
                          Panic surface: unreachable!() clusters and mutex-poison cascade #116
                          Closed
                          #240
                          Closed
                          Panic surface: unreachable!() clusters and mutex-poison cascade#116
                          #240
                          Labels
                          bugSomething isn't working
                          Description
                          @Tryanks
                          Tryanks
                          opened on Jul 19, 2026
                          Status — partially changed, still open (reviewed 2026-08-22)
                          The terminal was split into PTY and grid components, the big chat.rs was split into chat/mod.rs + chat/model.rs + components, and several unrelated crash paths were hardened — but the invariant/panic sweep itself is not complete.
                          Current evidence on main (e8a5f1cc)
                          1. Invariant aborts
                            • 8 production unreachable!() sites remain (test-module sites excluded): 5 in crates/ui/src/chat/mod.rs (302, 313, 375, 513, 778), plus crates/ui/src/chat/components/subagent.rs:39, crates/core/src/session.rs:1095, and crates/runtime/src/app/orchestrate.rs:931.
                            • The earlier crates/agent/src/acp.rsunreachable!() cluster is gone, and the count is down from 13; the remaining sites still turn presentation- and session-state assumptions into process aborts.
                          2. Mutex poisoning
                            • std::sync::Mutex with lock().unwrap() remains widespread: crates/agent/src/acp.rs (37 call sites), crates/term/src/grid_emulator.rs (9), crates/term/src/pty.rs (5), crates/term/src/pty_info.rs (1).
                            • A panic while holding any of these shared locks can cascade into later UI/reader-thread panics.
                          3. Child-pipe assumptions
                            • ACP launch still uses expect("piped stdin/stdout/stderr") after spawning the agent (crates/agent/src/acp.rs:327-329), and ACP terminal creation has the same stdout/stderr assumptions (acp.rs:2423-2424).
                            • These should surface structured start/terminal errors rather than aborting.
                          Direction
                          • Replace externally reachable unreachable!() branches with logged fallback/error events; keep debug_assert! for developer visibility.
                          • Use non-poisoning mutexes where appropriate, or recover poison explicitly when continuing is safe.
                          • Convert child-pipe expect calls and counter-overflow expects into propagated errors.
                          • Add targeted tests that inject unexpected variants, poisoned locks, and missing child pipes.
                          Acceptance criteria
                          No provider output, recoverable process-launch failure, or terminal worker panic can abort the application solely through these clusters.
                          Effort: M · Risk: LOW–MED
                          Metadata
                          Metadata
                          Assignees
                          No one assigned
                            Labels
                            bugSomething isn't working
                            Projects
                            No projects
                              Milestone
                              No milestone
                              Relationships
                              None yet
                              Development
                              No branches or pull requests
                              Issue actions
                              
, '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); }
})();
})();

                              Skip to content
                              Panic surface: unreachable!() clusters and mutex-poison cascade #116
                              Closed
                              #240
                              Closed
                              Panic surface: unreachable!() clusters and mutex-poison cascade#116
                              #240
                              Labels
                              bugSomething isn't working
                              Description
                              @Tryanks
                              Tryanks
                              opened on Jul 19, 2026
                              Status — partially changed, still open (reviewed 2026-08-22)
                              The terminal was split into PTY and grid components, the big chat.rs was split into chat/mod.rs + chat/model.rs + components, and several unrelated crash paths were hardened — but the invariant/panic sweep itself is not complete.
                              Current evidence on main (e8a5f1cc)
                              1. Invariant aborts
                                • 8 production unreachable!() sites remain (test-module sites excluded): 5 in crates/ui/src/chat/mod.rs (302, 313, 375, 513, 778), plus crates/ui/src/chat/components/subagent.rs:39, crates/core/src/session.rs:1095, and crates/runtime/src/app/orchestrate.rs:931.
                                • The earlier crates/agent/src/acp.rsunreachable!() cluster is gone, and the count is down from 13; the remaining sites still turn presentation- and session-state assumptions into process aborts.
                              2. Mutex poisoning
                                • std::sync::Mutex with lock().unwrap() remains widespread: crates/agent/src/acp.rs (37 call sites), crates/term/src/grid_emulator.rs (9), crates/term/src/pty.rs (5), crates/term/src/pty_info.rs (1).
                                • A panic while holding any of these shared locks can cascade into later UI/reader-thread panics.
                              3. Child-pipe assumptions
                                • ACP launch still uses expect("piped stdin/stdout/stderr") after spawning the agent (crates/agent/src/acp.rs:327-329), and ACP terminal creation has the same stdout/stderr assumptions (acp.rs:2423-2424).
                                • These should surface structured start/terminal errors rather than aborting.
                              Direction
                              • Replace externally reachable unreachable!() branches with logged fallback/error events; keep debug_assert! for developer visibility.
                              • Use non-poisoning mutexes where appropriate, or recover poison explicitly when continuing is safe.
                              • Convert child-pipe expect calls and counter-overflow expects into propagated errors.
                              • Add targeted tests that inject unexpected variants, poisoned locks, and missing child pipes.
                              Acceptance criteria
                              No provider output, recoverable process-launch failure, or terminal worker panic can abort the application solely through these clusters.
                              Effort: M · Risk: LOW–MED
                              Metadata
                              Metadata
                              Assignees
                              No one assigned
                                Labels
                                bugSomething isn't working
                                Projects
                                No projects
                                  Milestone
                                  No milestone
                                  Relationships
                                  None yet
                                  Development
                                  No branches or pull requests
                                  Issue actions