FIX: forked-pr-coverage.yml env-injection via untrusted artifact

[Sumit Sarabhai (sumitmsft)]

Work Item / Issue Reference

AB#46466

Summary

• Treat fork-produced coverage artifacts as untrusted input and validate their schema and values before use.
• Bind coverage comments to the triggering pull request instead of accepting an artifact-supplied PR number.
• Remove untrusted artifact propagation through GITHUB_ENV and reject unexpected files, unsafe URLs, control characters, and oversized values.
• Pin GitHub Actions to immutable commit SHAs and disable persisted checkout credentials.
• Add regression coverage for environment injection, cross-PR targeting, executable artifacts, and Markdown/URL injection.

Validation

• 12 targeted security regression tests passed.
• Changed workflow YAML parsed successfully.
• Black formatting checks passed.
• Native extension build completed successfully.

[Copilot]

Pull request overview

Hardens the forked PR coverage-comment pipeline by treating coverage artifacts as untrusted input, validating/normalizing the data used to generate PR comments, and reducing the privileged workflow’s exposure to artifact-driven environment injection.

Changes:

• Introduces a Python validator/comment builder (prepare_fork_coverage_comment.py) and a security-focused regression test suite.
• Refactors forked-pr-coverage.yml to validate artifacts + resolve the target PR from the triggering workflow context (not artifact-supplied data), and post/update a single sticky comment.
• Tightens the producer workflow (pr-code-coverage.yml) by removing artifact-supplied PR targeting fields, hardening multiline GITHUB_ENV usage, and pinning actions to SHAs.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
tests/test_fork_coverage_security.py	Adds regression tests for artifact schema validation, URL/markup injection, PR resolution, and workflow env-injection checks.
.github/workflows/pr-code-coverage.yml	Pins actions, disables persisted credentials, hardens multiline env export, and removes untrusted fields from the uploaded artifact payload.
.github/workflows/forked-pr-coverage.yml	Moves privileged workflow to validate downloaded artifacts + resolve PR from the event/commit association before commenting.
.github/scripts/prepare_fork_coverage_comment.py	Implements schema/value validation and safe comment construction for fork coverage artifacts.
.github/actions/post-coverage-comment/action.yml	Pins the sticky-comment action to an immutable SHA.

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[github-actions]

📊 Code Coverage Report

🔥 Diff Coverage 100%

🎯 Overall Coverage 82%

📈 Total Lines Covered:7368 out of 8963 📁 Project:mssql-python

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Diff Coverage

Diff: main...HEAD, staged and unstaged changes

No lines with coverage information in this diff.

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📋 Files Needing Attention

📉 Files with overall lowest coverage (click to expand)

mssql_python.pybind.logger_bridge.cpp: 59.2%
mssql_python.pybind.ddbc_bindings.h: 59.9%
mssql_python.pybind.logger_bridge.hpp: 70.8%
mssql_python.pybind.ddbc_bindings.cpp: 76.6%
mssql_python.__init__.py: 77.6%
mssql_python.row.py: 77.6%
mssql_python.ddbc_bindings.py: 79.6%
mssql_python.pybind.connection.connection_pool.cpp: 81.4%
mssql_python.pybind.connection.connection.cpp: 84.3%
mssql_python.logging.py: 85.5%

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[Gaurav Sharma (bewithgaurav)]

requesting changes - some issues wrt forked pr comments and refactoring suggestions to cut the PR short

[Gaurav Sharma (bewithgaurav)]

requesting changes - for a different blocker this time, added a couple of suggestions as well

[Gaurav Sharma (bewithgaurav)]

blocker: gh won't run this. --slurp and --jq can't be used together:

$ gh api --paginate --slurp "repos/.../pulls?state=open&per_page=100" --jq 'add'
the `--slurp` option is not supported with `--jq` or `--template`
exit 1

fails on every gh version, and the whole step goes with it
same combination at line 75 (commented there as well - with a better suggestion)

piping instead works:

gh api --paginate --slurp "repos/${GITHUB_REPOSITORY}/pulls?state=open&per_page=100" \
| jq 'add' > "$PULLS_FILE"

checked against the live api and all three fork PRs here resolve correctly through it

[Gaurav Sharma (bewithgaurav)]

optional: match the fork name too, not just the commit.

two forks sitting on the same commit would both match today, and then nobody gets a comment. harmless, just noticed it

[Gaurav Sharma (bewithgaurav)]

this has the same blocker as the line 60 one, I have a better suggestion which includes fixing that as well:

gh pr comment does find-or-create on its own, so this whole block collapses to one call.

gh pr comment "$PR_NUMBER" --repo "$GITHUB_REPOSITORY" \
--body-file "$COMMENT_FILE" --edit-last --create-if-none

18 lines down to 2. the script writes the body as markdown instead of wrapping it in json, same line either way. the argus writeup named this one directly, a plain gh pr comment call, so it stays on the no-node-action path you took.

if you do take it, the line 75 call goes with the block, so that one needs no fix.