chore: migrate dev environment from Nix flake to mise

Replace the Nix flake devShell with mise (mise.toml) for tool provisioning and
treefmt (treefmt.toml) for formatting. Delete flake.nix, flake.lock, the
Makefile, .envrc, and the devcontainer Dockerfile; CI, the format hook, the
devcontainer, and the docs now drive everything through mise tasks
(`mise run <task>` / `mise tasks`).

Key details:
- Tests run under LuaJIT with busted 2.2.0: the blocking-diff tools yield
  coroutines across pcall/C boundaries (which PUC Lua 5.1 forbids), and busted
  2.3.0 changed test-execution behavior the suite depends on. PUC `lua` is kept
  only to provide LuaRocks, which builds the rocks targeting LuaJIT.
- mise.lock pins resolved tool URLs/checksums (the integrity role flake.lock
  played); `mise run setup` builds busted/luacheck/luacov into ./.luarocks.
- treefmt.toml replicates the former treefmt-nix formatter set (nixpkgs-fmt
  dropped since no .nix files remain).
- Devcontainer regenerated via `mise generate devcontainer`.

Change-Id: If27a12690d9d608e71dd534759eeecd6d8fd4cd2
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Signed-off-by: Thomas Kosiewski <tk@coder.com>

Author: ThomasK33

.claude/hooks/format.sh

@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 #
 # Claude Code Hook: Format Files
-# Triggers after Claude edits/writes files and runs nix fmt
+# Triggers after Claude edits/writes files and runs treefmt (via mise)
 #
 # Environment variables provided by Claude Code:
 # - CLAUDE_PROJECT_DIR: Path to the project directory
@@ -75,18 +75,18 @@ main() {
     exit 1
   fi
 
-  log "${YELLOW}Formatting file with nix fmt...${NC}"
+  log "${YELLOW}Formatting file with treefmt...${NC}"
 
   # Change to project directory
   cd "${CLAUDE_PROJECT_DIR}"
 
-  # Run nix fmt on the file
-  if nix fmt "$FILE_PATH" 2>/dev/null; then
+  # Run treefmt on the file
+  if mise exec -- treefmt "$FILE_PATH" 2>/dev/null; then
     log "${GREEN}✓ Successfully formatted: $FILE_PATH${NC}"
     exit 0
   else
     EXIT_CODE=$?
-    log "${RED}✗ nix fmt failed with exit code $EXIT_CODE${NC}"
+    log "${RED}✗ treefmt failed with exit code $EXIT_CODE${NC}"
     log "${RED}This indicates the file has formatting issues that need manual attention${NC}"
 
     # Don't fail the hook - just warn about formatting issues

.devcontainer/Dockerfile

@@ -1,17 +1,12 @@
 {
   "name": "claudecode.nvim Development",
-  "build": {
-    "dockerfile": "Dockerfile"
-  },
+  "image": "mcr.microsoft.com/devcontainers/base:ubuntu",
   "features": {
-    "ghcr.io/devcontainers/features/git:1": {}
+    "ghcr.io/devcontainers-extra/features/mise:1": {}
   },
   "customizations": {
     "vscode": {
-      "settings": {
-        "terminal.integrated.defaultProfile.linux": "bash"
-      },
-      "extensions": ["jnoortheen.nix-ide"]
+      "extensions": ["hverlin.mise-vscode"]
     }
   },
   "postCreateCommand": "bash .devcontainer/post-create.sh",

.devcontainer/devcontainer.json

@@ -1,31 +1,33 @@
 #!/bin/bash
+set -euo pipefail
 
-# Source Nix environment
-. /home/vscode/.nix-profile/etc/profile.d/nix.sh
-
-# Verify Nix is available
-if ! command -v nix &>/dev/null; then
-  echo "Error: Nix is not installed properly"
+# Ensure the feature-installed mise is on PATH for this script.
+export PATH="$HOME/.local/bin:/usr/local/bin:$PATH"
+if ! command -v mise &>/dev/null; then
+  echo "Error: mise is not on PATH after the devcontainer feature install" >&2
   exit 1
 fi
 
-echo "✅ Nix is installed and available"
-echo ""
-echo "📦 claudecode.nvim Development Container Ready!"
-echo ""
-echo "To enter the development shell with all dependencies, run:"
-echo "  nix develop"
+# Build deps: PUC Lua builds from source, and the test rocks compile C modules.
+sudo apt-get -o Acquire::Retries=3 update
+sudo apt-get -o Acquire::Retries=3 install -y build-essential libreadline-dev unzip
+
+# Activate mise in interactive shells (puts the toolchain + fixtures/bin on PATH).
+if ! grep -qs 'mise activate bash' "$HOME/.bashrc"; then
+  echo 'eval "$(mise activate bash)"' >>"$HOME/.bashrc"
+fi
+
 echo ""
-echo "This will provide:"
-echo "  - Neovim"
-echo "  - Lua and LuaJIT"
-echo "  - busted (test framework)"
-echo "  - luacheck (linter)"
-echo "  - stylua (formatter)"
-echo "  - All other development tools"
+echo "📦 Provisioning the claudecode.nvim development environment with mise..."
+
+mise trust
+mise install
+mise run setup
+
 echo ""
-echo "You can also run development commands directly:"
-echo "  - make        # Run full validation (format, lint, test)"
-echo "  - make test   # Run tests"
-echo "  - make check  # Run linter"
-echo "  - make format # Format code"
+echo "✅ claudecode.nvim development environment ready."
+echo "   mise run all      # full validation (format, lint, test)"
+echo "   mise run test     # run tests"
+echo "   mise run check    # lint"
+echo "   mise run format   # format"
+echo "   mise tasks        # list all tasks"

.devcontainer/post-create.sh

@@ -16,11 +16,11 @@ concurrency:
   cancel-in-progress: ${{ github.ref != 'refs/heads/main' }}
 
 jobs:
+  # Unit/component tests run under LuaJIT with a mocked vim global (busted), so
+  # they do not need a real Neovim binary — hence no neovim-version matrix here.
+  # Real-Neovim coverage lives in the integration-tests job below.
   unit-tests:
     runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        neovim-version: ["stable", "nightly"]
 
     steps:
       - name: Checkout
@@ -29,38 +29,38 @@ jobs:
           fetch-depth: 0
           persist-credentials: false
 
-      - name: Setup Nix
-        uses: nixbuild/nix-quick-install-action@5bb6a3b3abe66fd09bbf250dce8ada94f856a703 # v30
+      # Build deps: PUC Lua builds from source, and the test rocks compile C modules.
+      - name: Install build dependencies
+        run: |
+          sudo apt-get -o Acquire::Retries=3 update
+          sudo apt-get -o Acquire::Retries=3 install -y build-essential libreadline-dev unzip
 
-      - uses: nix-community/cache-nix-action@135667ec418502fa5a3598af6fb9eb733888ce6a # v6.1.3
-        with:
-          primary-key: nix-claudecode-${{ runner.os }}-${{ hashFiles('**/*.nix', '**/flake.lock') }}
-          restore-prefixes-first-match: nix-claudecode-${{ runner.os }}-
-          gc-max-store-size-linux: 2G
-          purge: true
-          purge-prefixes: nix-claudecode-${{ runner.os }}-
-          purge-created: 0
-          purge-primary-key: never
+      - name: Set up mise
+        uses: jdx/mise-action@1648a7812b9aeae629881980618f079932869151 # v4.0.1
 
-      - name: Setup Neovim
-        uses: rhysd/action-setup-vim@8e931b9954b19d4203d5caa5ff5521f3bc21dcc7 # v1.4.2
+      # Cache the rock tree (rebuilt from luarocks.org otherwise); a miss just rebuilds.
+      - name: Cache Lua test rocks
+        uses: actions/cache@27d5ce7f107fe9357f9df03efb73ab90386fccae # v5.0.5
         with:
-          neovim: true
-          version: ${{ matrix.neovim-version }}
+          path: .luarocks
+          key: luarocks-${{ runner.os }}-${{ hashFiles('mise.toml') }}
+
+      - name: Install Lua test rocks
+        run: mise run setup
 
-      - name: Run Luacheck
-        run: nix develop .#ci -c make check
+      - name: Run luacheck
+        run: mise run check
 
       - name: Run tests
-        run: nix develop .#ci -c make test
+        run: mise run test
 
       - name: Check formatting
-        run: nix flake check
+        run: mise run format-check
 
       - name: Generate coverage report
         run: |
           if [ -f "luacov.stats.out" ]; then
-            nix develop .#ci -c luacov
+            mise exec -- luacov
 
             echo "Creating lcov.info from luacov.report.out"
             {
@@ -134,19 +134,8 @@ jobs:
           fetch-depth: 0
           persist-credentials: false
 
-      - name: Setup Nix
-        uses: nixbuild/nix-quick-install-action@5bb6a3b3abe66fd09bbf250dce8ada94f856a703 # v30
-
-      - uses: nix-community/cache-nix-action@135667ec418502fa5a3598af6fb9eb733888ce6a # v6.1.3
-        with:
-          primary-key: nix-claudecode-${{ runner.os }}-${{ hashFiles('**/*.nix', '**/flake.lock') }}
-          restore-prefixes-first-match: nix-claudecode-${{ runner.os }}-
-          gc-max-store-size-linux: 2G
-          purge: true
-          purge-prefixes: nix-claudecode-${{ runner.os }}-
-          purge-created: 0
-          purge-primary-key: never
-
+      # Neovim here comes from action-setup-vim (matrix-driven), independent of
+      # the mise.toml neovim pin used for local dev.
       - name: Setup Neovim
         uses: rhysd/action-setup-vim@8e931b9954b19d4203d5caa5ff5521f3bc21dcc7 # v1.4.2
         with:
@@ -159,4 +148,4 @@ jobs:
           ln -s "$(pwd)" ~/.local/share/nvim/site/pack/vendor/start/claudecode.nvim
 
       - name: Run integration tests
-        run: nix develop .#ci -c ./scripts/run_integration_tests_individually.sh
+        run: ./scripts/run_integration_tests_individually.sh

.envrc

@@ -6,6 +6,9 @@ luac.out
 *.zip
 *.tar.gz
 
+# Project-local Lua rock tree built by `mise run setup`
+/.luarocks/
+
 # Object files
 *.o
 *.os

.github/workflows/test.yml

@@ -10,12 +10,13 @@
 
 ## Build, Test, and Development Commands
 
-- `make check`: Syntax checks + `luacheck` on `lua/` and `tests/`.
-- `make format`: Format with StyLua (via Nix `nix fmt` in this repo).
-- `make test`: Run Busted tests with coverage (outputs `luacov.stats.out`).
-- `make clean`: Remove coverage artifacts.
+- Setup (one time): install [mise](https://mise.jdx.dev), then `mise install && mise run setup` to provision the toolchain and build the Lua test rocks. Activate mise in your shell (`eval "$(mise activate bash)"` in your rc) so bare tools like `busted`/`nvim` are on PATH; otherwise prefix with `mise exec --`. Run `mise tasks` to list all tasks.
+- `mise run check`: Syntax checks + `luacheck` on `lua/` and `tests/`.
+- `mise run format`: Format the tree with treefmt (replaces the former `nix fmt`).
+- `mise run test`: Run Busted tests with coverage (outputs `luacov.stats.out`).
+- `mise run clean`: Remove coverage artifacts.
   Examples:
-- Run all tests: `make test`
+- Run all tests: `mise run test`
 - Run one file: `busted -v tests/unit/terminal_spec.lua`
 
 ## Coding Style & Naming Conventions
@@ -32,13 +33,13 @@
 - File naming: `*_spec.lua` or `*_test.lua` under `tests/unit` or `tests/integration`.
 - Mocks/helpers: place in `tests/mocks` and `tests/helpers`; prefer pure‑Lua mocks.
 - Coverage: keep high signal; exercise server, tools, diff, and terminal paths.
-- Quick tip: prefer `make test` (it sets `LUA_PATH` and coverage flags).
+- Quick tip: prefer `mise run test` (it sets `LUA_PATH` and coverage flags).
 
 ## Commit & Pull Request Guidelines
 
 - Commits: Use Conventional Commits (e.g., `feat:`, `fix:`, `docs:`, `test:`, `chore:`). Keep messages imperative and scoped.
 - PRs: include a clear description, linked issues, repro steps, and tests. Update docs (`README.md`, `ARCHITECTURE.md`, or `DEVELOPMENT.md`) when behavior changes.
-- Pre-flight: run `make format`, `make check`, and `make test`. Attach screenshots or terminal recordings for UX-visible changes (diff flows, terminal behavior).
+- Pre-flight: run `mise run all` (format, lint, test). Attach screenshots or terminal recordings for UX-visible changes (diff flows, terminal behavior).
 
 ## Security & Configuration Tips