Instrument first-party libraries in coverage reports

[Amaury Chamayou (achamayou)]

Instrument first-party C++ libraries under COVERAGE=ON, propagating coverage-runtime linkage to their consumers while reporting only linked binaries.

Add per-file JSON export, framework/sample totals, and a CI guard for missing or unhit implementation code. Preserve existing exclusions and support source paths in renamed checkouts.

The expanded coverage denominator makes older percentages incomparable. A passing full Coverage run is still outstanding; earlier concurrent e2e runs did not pass.

[Copilot]

🔵 Needs a closer look

Resolve the coverage-history baseline and renamed-checkout path handling issues.

Pull request overview

Expands C++ coverage to first-party libraries with JSON reporting, instrumentation checks, and CI updates.

Changes:

• Instruments libraries and propagates coverage runtime linkage.
• Adds scoped totals, path handling, JSON export, and sentinel validation.
• Updates coverage CI and testing documentation.

File summaries

File	Description
scripts/tests/coverage_report_test.py	Tests coverage parsing and validation.
scripts/coverage.sh	Adds JSON export and path handling.
scripts/coverage_report.py	Generates scoped totals and instrumentation checks.
cmake/tools.cmake	Instruments libraries and propagates runtime linkage.
cmake/crypto.cmake	Enables coverage for the crypto library.
cmake/ccf_app.cmake	Enables coverage for CCF targets.
.github/workflows/coverage.yml	Runs coverage reporting and CI validation.
.github/skills/testing/SKILL.md	Documents the updated coverage workflow.

Review details

Suppressed comments (2)

.github/workflows/coverage.yml:91

• This run now emits a different TOTAL denominator because first-party library objects are included, but the existing history step still feeds pre-instrumentation logs into coverage_summary.py alongside this value. The resulting trend chart presents incomparable percentages as a continuous history; please reset/mark the baseline at this change or suppress the old points until a new baseline exists.

          python3 ../scripts/coverage_report.py coverage_html/coverage.json \
            --check-instrumentation | tee coverage_html/summary.md

scripts/coverage_report.py:46

• When the export retains the relative path produced by -ffile-prefix-map (for example CCF/src/crypto/base64.cpp), this prepends the renamed checkout and normalises to CCF/src/... instead of src/.... The framework files are then classified as Other, and every instrumentation sentinel is reported missing in the renamed-checkout case. Treat the mapped CCF/ prefix as rooted at source_dir.parent before applying the root stripping, and add that relative-path form to the regression test.

            path = (source_dir / entry["filename"]).resolve()
            filename = path.as_posix()
            for root in source_roots:
                if path.is_relative_to(root):
                    filename = path.relative_to(root).as_posix()

• Files reviewed: 8/8 changed files
• Comments generated: 0
• Review effort level: Lite

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