[myuron]

Summary

Adds a derivation that starts the wrapped Neovim headless with the user's config and fails on any startup error. A dotfiles CI can then catch a broken plugin bump with one line:

checks.${system}.nvim = config.programs.nvimx.env.check;

API

Both entry points share one implementation in nix/lib/check.nix:

• lib.mkCheck { env, configDir, ignoreErrors }.
• env.check: makeEnv gains optional configDir and check arguments. env.check throws a clear error if it is forced while configDir is null; the throw is lazy.
• Home-manager: the module passes configDir through and adds one option, programs.nvimx.check.ignoreErrors.
• Drv paths: env.wrapped and env.farm are unchanged (compared with main).
• configDir form: it must be a path literal or a store path. An absolute string fails at evaluation in pure mode, not inside the sandbox.

What the check does

It runs in the sandbox with a copy of configDir and temporary XDG/HOME directories, using the driver lua/nvimx/startup-check.lua.

• Loading: every plugin installed in the farm is loaded through lazy.load.
  • Dev plugins are outside the farm, so they are skipped by construction, and their "not installed" error is filtered out.
  • A plugin that is in the spec but missing from the lock fails with a "re-run nvimx-lock" hint.
  • A config that never calls lazy.setup() fails rather than passing with nothing checked.
• Error collection, done inside Neovim rather than by grepping stderr:
  • vim.ui_attach with ext_messages, keeping only error kinds;
  • a guard on vim.notify that also catches ERROR notifications from plugins that replace it, whether with a function or with a callable table such as nvim-notify. It stores each assigned function wrapped, so the common local orig = vim.notify chaining pattern calls the previous function and never loops. A depth counter records a chained ERROR only once.
  • v:errmsg is not used, because silent! sets it.
• Robustness:
  • timeout -k 10 120: plain SIGTERM can't stop nvim while it is busy in Lua. Codes 124 and 137 are both reported as a timeout.
  • A success sentinel, so a config that runs :qa during startup can't pass by exiting 0.
• Network-fetching plugins:
  • programs.nvimx.check.ignoreErrors / ignoreErrors takes plain substrings to allow.
  • NVIMX_CHECK=1 is exported so a config can switch such plugins off.
  • Trade-off: an ERROR that the user's own notify filter drops is still recorded; ignoreErrors is the way out.

Tests

• checks.startup-check:
  • the good, tolerated (missing dev plugin) and allowlisted configs must build;
  • env.check.runner runs on these broken fixtures, each expected to fail with a specific message: init error, error in a lazy-loaded config, replaced notify, a callable-table notifier like nvim-notify (vim.notify = require("notify")), chained notify + ERROR (reported exactly once, no hang), stale lock, no lazy, early quit;
  • a chained notify that only emits WARN must pass.
• checks.hm-module-startup-check: proves configDir and ignoreErrors reach makeEnv through the module.
• Mutations, each failing the check:
  • removing the dev-plugin skip;
  • removing the depth == 0 guard;
  • disabling the sentinel;
  • disabling the notify guard;
  • skipping lazy.load.

The 120 s timeout path itself is not exercised (too slow for CI).

Verification

• nix fmt -- --ci, nix flake check
• nix build .#checks.x86_64-linux.{startup-check,hm-module-startup-check}, nix eval .#checks.aarch64-darwin.{startup-check,hm-module-startup-check}.drvPath
• env.wrapped / env.farm drvPaths identical on main and on this branch.

Closes #79

🤖 Generated with Claude Code

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📥 Commits

Reviewing files that changed from the base of the PR and between 883733e and e5980e1.

📒 Files selected for processing: 20

• README.md
• lua/nvimx/startup-check.lua
• nix/home-manager/default.nix
• nix/lib/check.nix
• nix/lib/default.nix
• nix/lib/make-env.nix
• tests/checks/default.nix
• tests/checks/hm-module-startup-check.nix
• tests/checks/scripts/startup-check.sh
• tests/checks/startup-check.nix
• tests/fixtures/startup-check/chain-error/init.lua
• tests/fixtures/startup-check/chain-warn/init.lua
• tests/fixtures/startup-check/early-quit/init.lua
• tests/fixtures/startup-check/init-error/init.lua
• tests/fixtures/startup-check/lazy-config-error/init.lua
• tests/fixtures/startup-check/no-lazy/init.lua
• tests/fixtures/startup-check/notify-callable/init.lua
• tests/fixtures/startup-check/notify-error/init.lua
• tests/fixtures/startup-check/stale-lock/init.lua
• tests/fixtures/startup-check/tolerated/init.lua

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