fix: disable sccache for codecov

[LesnyRumcajs]

Summary of changes

Changes introduced in this pull request:

• codecov jobs are constantly failing; it might be because of the sccache which was recently introduced. Let's disable it for now.

Reference issue to close (if applicable)

Closes

Other information and links

Change checklist

• I have performed a self-review of my own code,
• I have made corresponding changes to the documentation. All new code adheres to the team's documentation standards,
• I have added tests that prove my fix is effective or that my feature works (if possible),
• I have made sure the CHANGELOG is up-to-date. All user-facing changes should be reflected in this document.

Summary by CodeRabbit

Release Notes

• Chores
  • Simplified continuous integration pipeline configuration by streamlining build infrastructure. Code coverage verification and all testing procedures remain unchanged and functional.

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[coderabbitai]

Walkthrough

The CI coverage workflow removes sccache compiler caching integration, including the RUSTC_WRAPPER environment variable, clang/clang++ compiler overrides, and SCCache configuration steps, while preserving all other CI functionality.

Changes

Cohort / File(s)	Summary
CI Workflow Configuration .github/workflows/coverage.yml	Removed sccache caching setup: eliminated RUSTC_WRAPPER, CC, and CXX environment variables that delegated to sccache; removed the "Configure SCCache variables" step that set SCCACHE_ENDPOINT, SCCACHE_BUCKET, and SCCACHE_REGION; removed the "Setup sccache" step. Code coverage and downstream CI steps remain unchanged.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

Possibly related PRs

• chore: resurrect codecov reports #6324: Directly conflicts with this PR on sccache handling in the same coverage workflow file—this PR removes sccache setup while #6324 adds or uses it.
• fix(ci): use large timeout for codecov CI job #6406: Modifies the same .github/workflows/coverage.yml file with SCCache-related changes, including lscpu step addition and SCCache configuration alterations.

Suggested labels

github_actions

Suggested reviewers

• sudo-shashank
• hanabi1224

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'fix: disable sccache for codecov' directly and specifically describes the main change in the PR: disabling sccache for codecov jobs.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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📜 Recent review details

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between bde1046 and 437d08e.

📒 Files selected for processing (1)

• .github/workflows/coverage.yml

🧰 Additional context used

🧠 Learnings (1)

📓 Common learnings

Learnt from: LesnyRumcajs
Repo: ChainSafe/forest PR: 5907
File: src/rpc/methods/state.rs:523-570
Timestamp: 2025-08-06T15:44:33.467Z
Learning: LesnyRumcajs prefers to rely on BufWriter's Drop implementation for automatic flushing rather than explicit flush() calls in Forest codebase.

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• GitHub Check: Coverage
• GitHub Check: Build forest binaries on Linux AMD64
• GitHub Check: tests-release
• GitHub Check: rubocop
• GitHub Check: cargo-publish-dry-run
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• GitHub Check: All lint checks

🔇 Additional comments (2)

.github/workflows/coverage.yml (2)

33-34: LGTM! Sccache correctly removed from compiler configuration.

The direct clang/clang++ invocations without the sccache wrapper are appropriate for this temporary mitigation.

One minor observation: the AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY environment variables (lines 31-32) may now be unused if they were solely for sccache's S3 bucket. Consider removing them in a follow-up if they're no longer needed.

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42-68: Job configuration looks good.

The coverage job is properly configured without sccache dependencies. All necessary steps for code coverage generation and upload are retained.

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