perf(ci): cache Rust compilation with sccache

[matthewevans]

Summary by CodeRabbit

• Chores
  • Improved Rust build performance in automated checks by enabling compilation caching.
  • Applied caching across linting, testing, and card-data validation workflows.

[coderabbitai]

📝 Walkthrough

Walkthrough

The CI workflow installs and enables sccache in the Rust lint, Rust test, and card-data gate jobs by configuring GitHub Actions caching and Rust compiler wrapper environment variables.

Changes

CI compilation caching

Layer / File(s)	Summary
Enable sccache across Rust CI jobs .github/workflows/ci.yml	The rust-lint, rust-test, and card-data-gate jobs install sccache and set SCCACHE_GHA_ENABLED=true and RUSTC_WRAPPER=sccache for subsequent commands.

Estimated code review effort: 2 (Simple) | ~10 minutes

Suggested reviewers: ntindle

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: enabling sccache to cache Rust compilation in CI.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch ship/perf-ci-cache-rust-compilation

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In @.github/workflows/ci.yml:
- Around line 49-55: Update the three sccache-enabled Rust jobs around the
“Enable sccache” steps to set CARGO_INCREMENTAL=0 in each job’s environment,
ensuring incremental compilation is disabled while preserving the existing
sccache configuration.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: d2a10795-a0c7-456e-b054-a6efbac8550d

📥 Commits

Reviewing files that changed from the base of the PR and between f027bd9 and 3c445c7.

📒 Files selected for processing (1)

• .github/workflows/ci.yml

[coderabbitai]

🚀 Performance & Scalability | 🟡 Minor | ⚡ Quick win

🧩 Analysis chain

🏁 Script executed:

#!/usr/bin/env bash
set -euo pipefail

while IFS= read -r file; do
  echo "== $file =="
  rg -n '^\[profile|^\s*incremental\s*=' "$file" || true
done < <(fd -t f '^Cargo\.toml$')

echo "== Workflow overrides =="
rg -n 'CARGO_INCREMENTAL|RUSTC_WRAPPER|SCCACHE_GHA_ENABLED' .github/workflows/ci.yml

Repository: phase-rs/phase

Length of output: 204

---

🏁 Script executed:

#!/usr/bin/env bash
set -euo pipefail

echo "== workflow =="
cat -n .github/workflows/ci.yml | sed -n '1,260p'

echo "== cargo tomls =="
find . -name Cargo.toml -print | sort | while IFS= read -r file; do
  echo "== $file =="
  cat -n "$file" | sed -n '1,220p'
done

Repository: phase-rs/phase

Length of output: 34951

---

🏁 Script executed:

#!/usr/bin/env bash
set -euo pipefail

echo "== config files =="
find . -path '*/.cargo/config.toml' -o -path './.cargo/config.toml' -o -path './Cargo.toml' | sort

echo "== incremental/profile search =="
rg -n 'incremental\s*=|\[profile\.ci\]|\[profile\.test\]|\[profile\.dev\]|CARGO_INCREMENTAL|profile ci' . \
  --glob '!.git' \
  --glob '!**/target/**' \
  --glob '!**/node_modules/**' || true

echo "== .cargo/config.toml =="
if [ -f .cargo/config.toml ]; then
  cat -n .cargo/config.toml
fi

Repository: phase-rs/phase

Length of output: 3531

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Disable incremental compilation for the sccache jobs
These Rust jobs don’t set CARGO_INCREMENTAL=0 or override incremental in the active Cargo profiles, so sccache may miss the main workspace compiles. Set CARGO_INCREMENTAL=0 for the three sccache-enabled jobs.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In @.github/workflows/ci.yml around lines 49 - 55, Update the three
sccache-enabled Rust jobs around the “Enable sccache” steps to set
CARGO_INCREMENTAL=0 in each job’s environment, ensuring incremental compilation
is disabled while preserving the existing sccache configuration.

Source: MCP tools