Use XDG_CACHE_HOME for the bootstrap cache directory

[wolveix]

Summary

Implements XDG Base Directory support for the bootstrap disk cache, addressing #35.

The default cache location changes from $HOME/.openrdap to $XDG_CACHE_HOME/openrdap, falling back to $HOME/.cache/openrdap when XDG_CACHE_HOME is unset or not an absolute path (relative values are ignored per the XDG spec).

This keeps non-essential cache files out of $HOME and lets users clear the cache predictably via $XDG_CACHE_HOME.

Changes

• bootstrap/cache/disk_cache.go: resolve the default Dir from $XDG_CACHE_HOME (or $HOME/.cache); InitDir now uses MkdirAll so the cache parent (e.g. ~/.cache) is created as needed.
• bootstrap/cache/disk_cache_test.go: add TestNewDiskCacheDir covering XDG set / unset / relative.
• Doc updates: bootstrap/client.go godoc, cli.go --cache-dir help, rdap.1 man page, README.md.

Notes

The legacy $HOME/.openrdap directory is not migrated or preferred. Since the bootstrap cache is regenerable, existing installs simply re-download the registry files once into the new location. Use --cache-dir to override.

Closes #35

Summary by CodeRabbit

• Bug Fixes

  • Bootstrap cache now uses the system XDG cache location with improved directory creation and error handling.

• Documentation

  • Updated README, CLI help text, and manual pages to reflect new cache directory defaults and usage table formatting.

• Tests

  • Added tests validating cache directory resolution across XDG/HOME environment scenarios.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 919d437b-d29d-4845-a6bb-cf7727bfc6d7

📥 Commits

Reviewing files that changed from the base of the PR and between 60b210e and 1fe21cd.

📒 Files selected for processing (1)

• bootstrap/cache/disk_cache.go

🚧 Files skipped from review as they are similar to previous changes (1)

• bootstrap/cache/disk_cache.go

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📝 Walkthrough

Walkthrough

Migrate bootstrap cache from $HOME/.openrdap/ to XDG Base Directory: $XDG_CACHE_HOME/openrdap/ with fallback $HOME/.cache/openrdap/. NewDiskCache() resolves XDG vs fallback. InitDir uses os.MkdirAll. Save always initializes dir, writes file, then reads modtime and updates lastLoadedModTime. Add TestNewDiskCacheDir for XDG/unset/relative cases. Update README, CLI help text, man page, and package docs.

🚥 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	Title accurately summarizes main change: switching cache default from ~/.openrdap to XDG_CACHE_HOME/openrdap.
Linked Issues check	✅ Passed	Implementation matches issue #35 requirements: defaults to ${XDG_CACHE_HOME:-~/.cache}/openrdap, respects XDG spec (ignores relative paths), documents the change, and allows override via --cache-dir.
Out of Scope Changes check	✅ Passed	All changes directly support XDG cache implementation: code logic (disk_cache.go), tests (disk_cache_test.go), and documentation (README, cli.go, bootstrap/client.go, rdap.1).
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feat/xdg-cache-home

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_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[coderabbitai]

🧹 Nitpick comments (2)

bootstrap/cache/disk_cache.go (1)

49-61: ⚡ Quick win

XDG resolution correct. Panic acceptable but could be clearer.

Lines 52-58 correctly ignore relative XDG_CACHE_HOME per spec, fall back to $HOME/.cache.

Line 55 panic when home dir unknown is harsh but defensible - environment is broken. Consider more specific message like "HOME environment variable not set or inaccessible" so user knows what's wrong.

🔍 Clearer panic message

-			panic("Can't determine your home directory")
+			panic("Cannot determine home directory: HOME environment variable not set or inaccessible")

bootstrap/cache/disk_cache_test.go (1)

17-47: 💤 Low value

Test coverage good. Cleanup error acceptable but could be explicit.

Lines 29-46 validate XDG scenarios correctly: absolute path used, unset falls back, relative ignored.

Line 25: Static analysis flagged unchecked os.RemoveAll error. In test cleanup, this is standard Go pattern - temp dir cleanup failure won't break test. Acceptable as-is, but can make intent explicit with _ = os.RemoveAll(home).

📝 Explicit ignore

-	defer os.RemoveAll(home)
+	defer func() { _ = os.RemoveAll(home) }()

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: f2100dac-aab1-4db6-96c8-865e6db6bcc3

📥 Commits

Reviewing files that changed from the base of the PR and between 5d37d55 and 60b210e.

📒 Files selected for processing (6)

• README.md
• bootstrap/cache/disk_cache.go
• bootstrap/cache/disk_cache_test.go
• bootstrap/client.go
• cli.go
• rdap.1