[petertriho]

Keeps the GitHub and GitLab items (issues, pull requests, merge requests, and mentions) in a cache on disk, keyed by the remote. Each git commit from a shell starts a new Neovim, and the old cache was in memory and keyed by buffer number, so each commit message waited for the network again. Now the first #, !, or @ in a new Neovim shows the items from the cache file and starts no gh or glab process.

Behavior

• The cache is in stdpath("cache")/cmp-git/<host>/<owner>/<repo>/. Each list has one JSON file. The file name has a hash of the query fields of its config (state, filter, limit, fields), so another config has its own file.
• All buffers and all source instances of one remote share the entries. A cache hit needs no gh repo set-default lookup.
• The cache keeps the raw items, and each request formats them with its own format config and trigger character.
• When the items are older than the new cache.ttl option (300 seconds by default), a request still gets them at once. One refresh starts in the background, with the default repository from gh, and the next request gets the new items. A refresh of the mentions gets all pages.
• A failed command or HTTP error is still not cached. A failed refresh keeps the old items and waits one more TTL.
• Only the user can read the cache: the directories are 0700, and the files are 0600. A write goes to a temporary file and then a rename, so that another Neovim never reads a part of a file.
• Commits and trailers stay in memory for each buffer. They are local, and a cold request takes 4 to 12 ms.

Command

• :CmpGitClearCache clears the items of the remote of the current buffer, and the cached commits and trailers of the buffer.
• :CmpGitClearCache! clears the items of all remotes, deletes the cache directory, and drops the commits and trailers of all buffers.

The new plugin/cmp_git.lua defines the command, so blink.cmp users get it without setup. The command loads its module only when it runs. It finds the remote with the config of each live core, because ssh_aliases or a GitLab path prefix can change the remote of a URL.

Results

A manual check in this repository with the real gh, three separate Neovim processes, and the cache in a temporary directory:

Request	Time to the items	gh processes
Cold	736 ms	3
New Neovim with the cache files	10.5 ms	none
New Neovim with files older than the TTL	11.3 ms	3, in the background after the answer

make bench-compare REF=main, best of 2 runs:

Case	main	This branch
e2e/github_issues_and_prs/disk (new)	-	0.74 ms, no processes
e2e/github_mentions/disk (new)	-	0.11 ms, no processes
e2e/github_issues_and_prs/warm	0.15 ms	0.42 ms
e2e/github_mentions/warm	0.06 ms	0.12 ms
startup/setup	0.80 ms, 171 KB	0.78 ms, 174 KB
startup/require_all	1.92 ms, 392 KB	2.15 ms, 441 KB

• The disk cases are a new Neovim with the files of an earlier session. On main, this request is cold (about 8 to 10 ms with the fake gh, plus the network).
• The warm cases are slower because each cache hit now formats the raw items, as the commits capability already does.
• The comparison reports one regression, startup/require_all. This case loads every module, and the branch adds two: cmp_git.cache and cmp_git.commands. setup and a declined request still load no new module.

Changes

• 9be94b9: the test hooks and the benchmarks set XDG_CACHE_HOME to a temporary directory.
• 0f875b2: the new cmp_git.cache module, with the entries, the file format, the atomic write, the TTL check, the refresh state, and the clear functions.
• 6e72ad8: the GitHub and GitLab sources and their capabilities use the cache. Adds the cache.ttl option.
• 438b445: :CmpGitClearCache[!].
• fc192a7: the cold benchmark cases also clear the cache. The new disk cases measure a new session.
• effd1f2: a "Cache" section in docs/configuration.md, and the cache.ttl default in the README.

Tests

• make ci passes: format check, lint, type check, and tests.
• make test passes in the nvim-0_12_0 dev shell.
• New tests cover the file format and the modes, the key encoding, misses for invalid files, the background refresh and its failure, a clear during a fetch, a new session that reads the files without gh, and both forms of the command.