pin nvim-treesitter in CI

CI now installs a fixed nvim-treesitter commit and minimal tests only require a small parser set, failing fast with a helpful error if parsers are missing.

1 files changed, 34 insertions, 11 deletions

diff --git a/scripts/tests/minimal.vim b/scripts/tests/minimal.vim
index a8d3d7d..928594b 100644
--- a/scripts/tests/minimal.vim
+++ b/scripts/tests/minimal.vim
@@ -21,18 +21,41 @@ runtime! plugin/plenary.vim
 runtime! plugin/nvim-treesitter.lua
 
 lua <<EOF
-local required_parsers = {
-    'c', 'cpp', 'go', 'lua', 'php', 'python', 'typescript', 'javascript', 'java', 'ruby', 'tsx', 'c_sharp', 'vue'
-}
-local installed_parsers = require'nvim-treesitter.info'.installed_parsers()
-local to_install = vim.tbl_filter(function(parser)
-  return not vim.tbl_contains(installed_parsers, parser)
-end, required_parsers)
+local required_parsers = { "lua", "typescript", "go"}
+
+local function missing_parsers(parsers)
+  local missing = {}
+  local buf = vim.api.nvim_create_buf(false, true) -- false: no list, true: scratch buffer
+  for _, lang in ipairs(parsers) do
+    local ok = pcall(vim.treesitter.get_parser, buf, lang)
+    if not ok then
+      table.insert(missing, lang)
+    end
+  end
+  vim.api.nvim_buf_delete(buf, { force = true })
+  return missing
+end
+
+local to_install = missing_parsers(required_parsers)
 if #to_install > 0 then
   -- fixes 'pos_delta >= 0' error - https://github.com/nvim-lua/plenary.nvim/issues/52
-  vim.cmd('set display=lastline')
-  -- make "TSInstall*" available
-  vim.cmd 'runtime! plugin/nvim-treesitter.vim'
-  vim.cmd('TSInstallSync ' .. table.concat(to_install, ' '))
+  vim.cmd("set display=lastline")
+
+  -- Only attempt installation if nvim-treesitter provided the command.
+  if vim.fn.exists(":TSInstallSync") == 2 then
+    -- make "TSInstall*" available
+    vim.cmd("runtime! plugin/nvim-treesitter.vim")
+    vim.cmd("TSInstallSync " .. table.concat(to_install, " "))
+  end
+
+  -- Re-check and fail fast with a helpful message.
+  local still_missing = missing_parsers(required_parsers)
+  if #still_missing > 0 then
+    error(
+      "Missing Tree-sitter parsers: "
+        .. table.concat(still_missing, ", ")
+        .. "\nInstall them via :TSInstallSync <langs> or ensure nvim-treesitter is on runtimepath."
+    )
+  end
 end
 EOF