fix(cache): resolve pub cache path from PUB_CACHE for cross-OS runners

[cappy-dev]

On behalf of @Project516

Problem

The Cache pub step hardcoded path: ~/.pub-cache:

- name: Cache pub
  uses: actions/cache@v6
  with:
    path: ~/.pub-cache
    key: ${{ runner.os }}-pub-${{ hashFiles('pubspec.lock') }}

The cache key branches on ${{ runner.os }}, so the step is clearly meant to run on more than one runner OS. But Flutter does not write its packages to ~/.pub-cache on Windows. On a windows-latest job, flutter pub get populates %LOCALAPPDATA%\Pub\Cache, so this step was saving and restoring a directory Flutter never touches. The pub restore was a no-op there every run, and a stale ~/.pub-cache snapshot kept getting written back into the cache.

Fix

subosito/flutter-action@v2 already exports PUB_CACHE to the job environment, pointing at the directory flutter pub get actually populates on the current runner:

• Linux and macOS: ~/pub-cache (that is, $HOME/.pub-cache)
• Windows: %LOCALAPPDATA%\Pub\Cache

This change caches that path directly:

path: ${{ env.PUB_CACHE }}

Because env vars written to GITHUB_ENV by a prior step are available to later steps in the same job, the Install Flutter step's PUB_CACHE is already set by the time Cache pub evaluates its path.

Behavior

• Linux / macOS: PUB_CACHE equals ~/.pub-cache, so this is a no-op there.
• Windows: the step now caches the directory Flutter actually uses, instead of a phantom ~/.pub-cache, so the pub restore starts hitting on windows-latest.

Verification

• action.yml parses as valid YAML (yaml.safe_load).
• No em dashes used anywhere in the diff or this body.
• One commit, authored as cappy-dev <cappy-dev@users.noreply.github.com>.

Summary by CodeRabbit

• New Features

  • Improved Flutter package caching across runner operating systems by using the configured pub cache location.

• Documentation

  • Added guidance on platform-specific pub cache paths.
  • Clarified that cache keys should remain OS-specific to prevent incompatible cache reuse.

[cappy-dev]

cc @Project516

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: b4198d70-f45a-418e-8d12-55e5b059dbc1

📥 Commits

Reviewing files that changed from the base of the PR and between 20a31f9 and 15f445c.

📒 Files selected for processing (2)

• README.md
• action.yml

---

📝 Walkthrough

Walkthrough

The action now uses PUB_CACHE for Flutter pub caching. The README documents platform-specific cache paths and OS-specific cache keys.

Changes

Pub cache configuration

Layer / File(s)	Summary
Resolve and document the pub cache action.yml, README.md	action.yml uses ${{ env.PUB_CACHE }} instead of ~/.pub-cache. README.md documents platform-specific paths and cache keys.

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

Poem

I’m a rabbit with cache to share,
PUB_CACHE finds it everywhere.
Linux, macOS, Windows agree,
OS-specific keys keep builds tidy.
A hop, a key, a cache in place—
Pub dependencies leave no trace.

🚥 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 clearly and concisely describes the main cache path change for cross-OS runners.
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.

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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 `@action.yml`:
- Line 33: Correct the documented Linux/macOS pub cache path from ~/pub-cache to
~/.pub-cache in action.yml lines 33-33 and README.md lines 44-44; update both
descriptions consistently without changing surrounding content.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

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

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 8caa2330-cdfc-4829-8e22-df89abea30ec

📥 Commits

Reviewing files that changed from the base of the PR and between 4998a3d and 20a31f9.

📒 Files selected for processing (2)

• README.md
• action.yml

[Project516]

Verified the finding against current code — still valid. Flutter's default PUB_CACHE on Linux/macOS is ~/.pub-cache, not ~/pub-cache; both action.yml and README.md had it wrong. Fixed both descriptions consistently (commit 15f445c). YAML re-validated with yaml.safe_load. Docstring coverage is not applicable — changed files are YAML and README, no functions.