Files
OneCAD-Simulation/docs/crash-reports.md
jyvikoandClaude Opus 5.5 af9b4bb222 app: startup steps in the crash journal, and a Windows exception filter (#299)
egui-wgpu's startup hook and the app's own steps (window, app setup, viewport
pipelines, first frame, running) go into the journal. On Windows,
native_crash.rs (adapted from SolidCraft, the only module allowed unsafe code;
the app crate now denies instead of forbids it) writes the exception code,
faulting module and offset and a minidump. A nightly/on-demand CI job runs the
app's tests on Windows, including a child that faults on purpose.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UhhZMBTviDQxZvwnyP89fo
2026-10-16 01:11:58 -04:00

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Crash reports, the log file and Report a Bug

Privacy

No crash report, log line or model is uploaded automatically. Crash reports and the log stay on this computer (anonymous usage, if you agreed to share it, never carries them: see privacy.md). The only way they leave it is Help › Report a Bug (or Report It… after a crash), which opens a GitHub issue form in your browser; you read it there and submit it, or not.

Help › Crash Reports… lists every saved report (when, what, how many times), each with Report…, Copy Path and Delete, and Delete All (diagnostics.crash_reports, diagnostics.crash_reports.delete).

What a bug report carries:

Always (you can edit it) Only with Share my session Only with Include the model file as well
the version and OS, what happened (the last error by default), for a crash its message, place and backtrace top; your home folder is shown as ~ the commands that built the model (fieldcraft-session.json, replayable with fieldcraft-cli run); they can name your files the model (model.fieldcraft), which you attach yourself

The form shows exactly what will be filled in before you click Open GitHub Issue. GitHub refuses long new-issue links, so a session that does not fit goes out as a file instead: it is saved to bug-reports/<time>/ in the data folder below and copied to the clipboard, and the issue text says to attach or paste it. The model is always a file you attach.

Where things are

The app's data folder holds recovery/, crashes/, logs/ and bug-reports/:

System Folder
macOS ~/Library/Application Support/FieldCraft
Linux ~/.local/share/fieldcraft (or $XDG_DATA_HOME/fieldcraft)
Windows %LOCALAPPDATA%\FieldCraft

Runs driven by automation (--control, or CI set) use fieldcraft-automation/ in the temporary folder instead, so test runs never reach your folders. FIELDCRAFT_CRASH_DIR moves the crash folder, FIELDCRAFT_RECOVERY_DIR the recovery folder. The browser build keeps no crash folder and logs to the browser console.

The log file

logs/fieldcraft.log: one line per record, time LEVEL [pid] target: message. Past 2 MB it becomes fieldcraft.log.1 and a new one starts. Warnings and errors also go to the standard error stream.

Crash reports

crashes/<YYYYMMDD-HHMMSS>-<signature>/:

  • report.json ("format": "fieldcraft-crash/1"): kind (command_panic: a command hit an internal error, caught, the model left unchanged; recovered_panic: one caught inside a command; panic: an internal error outside commands; unclean_exit: the app ended without a clean exit — an abort, a stack overflow, a crash in a graphics driver, the process being killed outright (SIGKILL) — found at the next start), message, location, thread, backtrace, app, system, command, recent_commands (up to 32), last_activity (the last control request, such as control ui.capture), startup_phase ({step, ms}: the step a run that never drew its first frame died in), native (Windows: what the exception filter caught), base, count, first_seen, last_seen, notes; system.environment names the renderer, GPU and driver
  • model.fieldcraft: the model the replay starts from
  • replay.json: {"commands": [{command, params}, …]}
  • log.txt: the crashed run's lines of the log
  • minidump.dmp (Windows, a crash in native code): open it with WinDbg or Visual Studio

Startup steps and native crashes

While the app gets up, the journal keeps the step it is in: the app's own (window, app setup, viewport pipelines (shader compile), first frame, and running once a frame was presented) and egui-wgpu's in between (graphics instance, window surface, adapter request, adapter chosen, when the renderer is recorded, device creation, egui renderer (shader compile), surface configure, first frame (present)). A run that dies before running is reported "during startup (device creation, 1.2 s after launch)", so a graphics driver crash names its step.

On Windows an unhandled-exception filter (apps/fieldcraft/src/native_crash.rs) catches a crash in native code (an access violation in a graphics driver, a stack overflow): before the process goes it writes the exception code, the faulting module and the offset into it, and a minidump, next to the journal. The next start puts them into the report: "crashed with EXCEPTION_ACCESS_VIOLATION (0xC0000005) in igvk64.dll+0x64EA72 during startup (device creation…)", backtrace the code, the module and offset, and the thread, native the raw fields, and minidump.dmp. After a stack overflow there is no stack left for a minidump; the rest is still written.

The next start after a crash asks "FieldCraft closed unexpectedly": Report It… opens Report a Bug for that report.

For agents

From List One report Replay
Command (MCP execute, control channel, scripts) diagnostics.crash_reports diagnostics.crash_report {id}
CLI fieldcraft-cli crashes [--json] fieldcraft-cli crashes show <id> fieldcraft-cli crashes replay <id>

crashes replay opens the report's model, runs its commands (files they write can only go to a scratch folder) and says whether the same internal error happens again. crashes dir prints the folder, crashes clear [<id>] deletes reports. diagnostics.bug_report returns the draft (link, fields, attachments) without opening anything; over the control channel ui.start diagnostics.bug_report opens the form, ui.prompt {"answer": "set", …} sets its fields, and ui.inspect shows the draft. Only a click opens the browser.

Check that reporting works: with FIELDCRAFT_CRASH_TEST=1, diagnostics.crash_test {mode} crashes on purpose: panic, recovered or abort (reported at the next start).

A request to terminate is no crash: on Linux and macOS, SIGTERM (kill PID) and SIGINT (Ctrl-C) close the window as Close does (unsaved work is autosaved for recovery, the journal ends, no report). A second signal ends the app at once.

How it stays cheap and small

The app keeps a journal of the window's top-level commands (crashes/sessions/*.jsonl, at most 512 KB, two small writes per command that changes the model, none for commands that only read), restarted from each autosave and each model opened. A clean exit deletes it; it is locked while its app runs, so a journal nobody holds belongs to an app that died. A crash is identified by its place and message, numbers ignored: repeats only raise count. At most 5 new reports per run, 20 reports, 100 MB, 90 days; a model over 20 MB is not copied. Tests, the CLI and the browser build never install the hook.

Adapted from SolidCraft's crash reports (MIT OR Apache-2.0, see ATTRIBUTION.md).