ci-fix-port

name	ci-fix-port
description	Fetch CI build failure logs from GitHub Actions or PRs, diagnose the root cause, and fix the failing port or patch. Use when: a CI job fails after a port upgrade, a patch no longer applies, or a build option changed upstream.
argument-hint	pr=<number|url>; run=<id|url>; job=<name>; port=<name>; mode=diagnose|fix

CI Fix Port Workflow

Use this skill to pull build failure information from GitHub Actions, diagnose the cause, and fix the affected port or patch.

Repository: atframework/cmake-toolset (remote may be owent/cmake-toolset)

Prerequisites

The agent needs access to GitHub data. Try these sources in order and use the first that works:

1. GitHub MCP tools (mcp_github_*) — search for mcp_github with tool_search_tool_regex
2. gh CLI — run gh --version to test
3. GitHub REST API (unauthenticated) — works for public repos, job metadata and annotations; log download needs a token
4. fetch_webpage — read job HTML pages or API JSON directly

Fallback strategy: When log download returns 403 or "Sign in to view logs", switch to the indirect diagnosis methods in Phase 3 instead of retrying. Do not waste time on blocked endpoints.

Workflow

Phase 1: Identify the Failure

Parse user input for:

• pr= — PR number or URL
• run= — Actions run ID or URL
• job= — job name filter (e.g., gcc.no-rtti.test)
• port= — port name hint (optional)
• mode= — diagnose (read-only) or fix (default)

If no input is given, auto-detect:

1. Check the current branch and its remote tracking.
2. Find the latest PR targeting main from that branch, or the latest CI run on that branch.
3. Use fetch_webpage with the GitHub API:

   https://api.github.com/repos/{owner}/{repo}/actions/runs?branch={branch}&per_page=5
   

Gather job data:

1. Fetch the run's job list via API:

   /actions/runs/{run_id}/jobs?per_page=30
   

2. Classify each job by status and conclusion.
3. For failed jobs, record: name, duration (started_at to completed_at), runner labels.
4. Also fetch the last successful run on main for the same jobs — this confirms whether the failure is a regression.

Phase 2: Fetch Logs

Try to get actual log text using the methods below. If all fail, proceed to Phase 3 with indirect methods.

Option A: gh CLI

gh run view <run-id> --repo owent/cmake-toolset \
  --log-failed

Option B: GitHub REST API (authenticated)

Invoke-RestMethod `
  "$base/actions/jobs/<job-id>/logs" `
  -Headers @{
    Authorization = "Bearer $env:GITHUB_TOKEN"
  }

Option C: Check-run annotations

Even without log access, annotations contain error summaries:

/repos/{owner}/{repo}/check-runs/{job-id}/annotations

These are usually just "Process completed with exit code 1" but occasionally contain cmake error lines.

Option D: fetch_webpage on job HTML

https://github.com/{owner}/{repo}/actions/runs/{run_id}/job/{job_id}

Note: This often returns "Sign in to view logs" for private repos or when unauthenticated.

Efficient Log Reading

CI logs are very large. The build pipeline outputs all port build logs first, then prints the failing port's CMakeConfigureLog.yaml at the end. Do not read the entire log sequentially — this wastes context and tokens. Instead:

1. Search for error locations first. Use Select-String (PowerShell) or grep to find lines containing error, FAILED, fatal error, CMake Error, or ATFRAMEWORK_CMAKE_TOOLSET_THIRD_PARTY_CI_MODE in the downloaded log file.
2. Read targeted sections around the matched error positions (e.g., 50–100 lines of context before and after each error hit).
3. Check the tail first — the last 200–500 lines often contain the CMakeConfigureLog.yaml dump and the final error summary, which are the most diagnostic.
4. Skip successful port output. If the error is in port X, skip the build logs for ports A–W that succeeded. Search for the port name to jump directly to its section.
5. When using gh run view --log-failed, the output is already filtered to failed steps, but can still be large. Apply the same search-first strategy.

Phase 3: Diagnose the Failure

With logs available

Parse the log output and classify the failure:

Pattern	Likely Cause
error: patch failed / git apply error	Patch no longer applies cleanly
Unknown CMake command / option error	Deprecated or renamed build option
fatal error: … not found	Missing dependency or include order
undefined reference / link error	ABI or library mismatch
FAILED: … test	Runtime test regression
Could not find … package / include could not find	Config-package bug or find_package failure
Cross-compile host tool error	Host-tool not built or not found
-lc++abi / compiler not found	CI environment change (runner OS update)

Without logs (indirect diagnosis)

When logs are inaccessible, use these strategies:

1. Timing analysis — classify failures by duration:

   • < 2 min: configuration/cmake error or CI script error (compiler detection, environment)
   • 2–10 min: early build failure (first port fails to configure or compile)
   • 10–30 min: late build failure (port compiles but linking or later port fails)
   • > 30 min: test failure or final link stage

2. Platform grouping — if all MSVC jobs fail but Linux passes, the issue is platform-specific. Similarly for macOS-only failures.

3. BUILD_SHARED_LIBS grouping — if shared jobs fail but static passes (or vice versa), the issue involves library type handling (config packages, DLL exports, etc.). Note: the actual shared/static decision per port is resolved by project_third_party_check_build_shared_lib() in ports/Configure.cmake: ${FULL_PORT_NAME}_USE_SHARED > _USE_STATIC > BUILD_SHARED_LIBS / ATFRAMEWORK_USE_DYNAMIC_LIBRARY

   default static. A port may be static even when BUILD_SHARED_LIBS=ON if its _USE_STATIC is set.

4. Diff analysis — compare main..dev changes:

   • Which ports were upgraded?
   • Which patches were added/modified?
   • Were CI scripts changed?
   • Were core modules (ProjectBuildTools.cmake, FindConfigurePackage.cmake) changed?

5. Local reproduction — the most powerful tool when logs are unavailable. Build the suspected port locally and test find_package:

   # Example: test a port's config package
   cmake -S <upstream-src> -B build `
     -DBUILD_SHARED_LIBS=OFF `
     -DCMAKE_INSTALL_PREFIX=install
   cmake --build build --target install
   # Then test find_package:
   cmake -S test_project -B test_build `
     -DCMAKE_PREFIX_PATH=install
   

6. CI script analysis — read ci/do_ci.sh and ci/do_ci.ps1 for the failing job's configuration. Check for:

   • Combined -D flags in a single quoted string (PowerShell bug)
   • Platform-specific detection logic (e.g., clang version loops on macOS)
   • Environment assumptions that may break with runner OS updates

7. Compare with last main CI — fetch the last successful main run's jobs to confirm the same jobs passed before. This isolates regressions from pre-existing flakiness.

Record for each failure:

• failing job name, platform, and runner labels
• failure duration (fast vs slow)
• exact error message (if available)
• which port and version is involved
• which patch file (if any) was being applied
• BUILD_SHARED_LIBS value for the job
• whether the same job passed on main

Phase 4: Fix the Port

Based on diagnosis, apply the appropriate fix:

Config-package bug

This is a common issue when upstream cmake config files (<Pkg>Config.cmake) have bugs:

1. Build the port locally with the same BUILD_SHARED_LIBS setting as the failing CI job.
2. Inspect the installed cmake config files (usually in lib/cmake/<Pkg>/).
3. Look for unconditional include() without OPTIONAL, missing target aliases, or assumptions about which components are installed.
4. Add fixes to the port's patch file — patch the upstream *Config.cmake.in template.
5. Test by running find_package(<Pkg> REQUIRED) in a minimal test cmake project.

Patch failure

Follow patch-workflow.md:

1. Clone the target upstream version into test/third_party/packages/.
2. Test if the existing patch applies: git apply --check <patch>.
3. If it fails, inspect the conflict and create a new patch for the target version.
4. If cross-compiling patch, test .cross.patch separately.
5. Clean up test/third_party/packages/ afterward.

Deprecated build option

Follow deprecated-options.md:

1. Identify the removed/renamed option from upstream changelog or CMake files.
2. Add version-conditional logic in the port cmake file.

Dependency or include-order issue

1. Check test/CMakeLists.txt for correct include order.
2. Check upstream MODULE.bazel / CMakeLists.txt for changed dependency pins.
3. Update the port's version pin or dependency order.

CI environment issue

When the failure is caused by runner OS changes, not port code:

1. Check the failing CI script section (do_ci.sh / do_ci.ps1) for the affected job.
2. Identify environment assumptions (e.g., -lc++abi on macOS, versioned compiler binaries, SDK paths).
3. Add fallback logic to handle both old and new environments. For example:

   # Fallback: try without -lc++abi (macOS bundles
   # it into libc++)
   cmd1 || cmd1_without_abi || FAIL=1
   

4. Verify the fix doesn't break the corresponding Linux job that uses the same CI script section.

Cross-compilation failure

Follow cross-compilation.md.

Phase 5: Verify the Fix

1. If the fix is a patch, test it locally:

   cd test/third_party/packages/<port>-<version>
   git -c "core.autocrlf=input" apply --check <patch>
   

2. If the fix touches a config package, do a full local verification:

   • Build the port with the patched source
   • Install it to a temp prefix
   • Run find_package() in a test cmake project
   • Test with both BUILD_SHARED_LIBS=ON and OFF if both variants are used in CI

3. Review test/CMakeLists.txt, .github/workflows/build.yaml, and ci/do_ci.* for related job combinations that may be affected.

4. Clean up all local test artifacts:

   • test/third_party/packages/<port>-*
   • test/build_* temp directories

5. Summarize: what failed, root cause, files changed, and any remaining risks.

Important Rules

• Pre-commit formatting is mandatory. Before committing, run cmake-format -i on every modified .cmake, .cmake.in, and CMakeLists.txt file (excluding test/third_party/ and test/build_jobs_*/). Alternatively run bash ci/format.sh to format the entire tree. CI will reject unformatted files.
• Always fetch actual logs first. If unavailable, use indirect diagnosis (timing, platform grouping, local reproduction). Do not guess from job name.
• Match the exact failing platform and compiler. A fix for GCC may not apply to MSVC or cross-compile jobs.
• Reuse existing patches when the same-minor patch still applies. Only create a new patch file when content actually differs.
• Test .cross.patch separately from normal patches.
• Clean up test/third_party/packages/ and any temp build directories after testing.
• Do not remove repository-specific guards (RTTI, exceptions, compiler-version, backend exclusions) when fixing a build failure — they encode real compatibility constraints.
• Config packages are a common failure mode. When CMAKE_FIND_PACKAGE_PREFER_CONFIG=TRUE is set (as in this repo), all find_package calls prefer config mode. Upstream *Config.cmake bugs surface immediately.
• Always test patches with core.autocrlf=input since the repo uses this setting.
• Runner OS updates can break CI scripts without any code changes. Always compare with the last successful main CI run to distinguish environment regressions from code regressions.