fix(grep): explain ignore file failures

Author: mhiro2

lua/peekstack/providers/grep.lua

@@ -4,6 +4,36 @@ local notify = require("peekstack.util.notify")
 
 local M = {}
 
+---@param text string?
+---@return string
+local function compact_message(text)
+  local message = (text or ""):gsub("%s+", " "):gsub("^%s+", ""):gsub("%s+$", "")
+  if message == "" then
+    return "unknown error"
+  end
+  return message
+end
+
+---@param stderr string?
+---@return boolean
+local function is_ignore_file_error(stderr)
+  local message = compact_message(stderr):lower()
+  return message:find(".gitignore", 1, true) ~= nil
+    or message:find(".ignore", 1, true) ~= nil
+    or message:find(".rgignore", 1, true) ~= nil
+    or (message:find("ignore", 1, true) ~= nil and message:find("glob", 1, true) ~= nil)
+end
+
+---@param stderr string?
+---@return string
+local function format_failure_message(stderr)
+  local message = compact_message(stderr)
+  if is_ignore_file_error(stderr) then
+    return "rg failed; check .gitignore/.ignore patterns or encoding: " .. message
+  end
+  return "rg failed: " .. message
+end
+
 ---@param line string
 ---@return string?, integer?, integer?, string?
 local function parse_rg_line(line)
@@ -56,7 +86,7 @@ function M.search(_, cb)
     vim.system({ "rg", "--vimgrep", "--max-count=1000", "--", query }, { text = true }, function(result)
       vim.schedule(function()
         if result.code ~= 0 and result.code ~= 1 then
-          notify.warn("rg failed: " .. (result.stderr or "unknown error"))
+          notify.warn(format_failure_message(result.stderr))
           cb({})
           return
         end
@@ -68,5 +98,6 @@ end
 
 ---Expose parser for tests.
 M._parse_output = parse_rg_output
+M._format_failure_message = format_failure_message
 
 return M

tests/grep_provider_spec.lua

@@ -1,5 +1,25 @@
 describe("peekstack.providers.grep", function()
   local grep = require("peekstack.providers.grep")
+  local original_notify
+  local original_system
+  local original_input
+  local notifications
+
+  before_each(function()
+    original_notify = vim.notify
+    original_system = vim.system
+    original_input = vim.ui.input
+    notifications = {}
+    vim.notify = function(msg, level)
+      table.insert(notifications, { msg = msg, level = level })
+    end
+  end)
+
+  after_each(function()
+    vim.notify = original_notify
+    vim.system = original_system
+    vim.ui.input = original_input
+  end)
 
   it("parses vimgrep output with Unix paths", function()
     local output = "/tmp/sample.lua:3:5:hello"
@@ -23,4 +43,41 @@ describe("peekstack.providers.grep", function()
     assert.equals("hit", items[1].text)
     assert.is_true(items[1].uri:find("sample.lua", 1, true) ~= nil)
   end)
+
+  it("formats ignore-file failures with a targeted hint", function()
+    local message = grep._format_failure_message("error reading .gitignore: invalid UTF-8")
+
+    assert.equals(
+      "rg failed; check .gitignore/.ignore patterns or encoding: error reading .gitignore: invalid UTF-8",
+      message
+    )
+  end)
+
+  it("warns with the ignore hint when rg reports ignore file issues", function()
+    local items = nil
+
+    vim.ui.input = function(_, cb)
+      cb("sample")
+    end
+    vim.system = function(_, _, cb)
+      cb({
+        code = 2,
+        stdout = "",
+        stderr = "error reading .ignore: invalid UTF-8",
+      })
+    end
+
+    grep.search({}, function(result)
+      items = result
+    end)
+
+    vim.wait(100, function()
+      return items ~= nil
+    end)
+
+    assert.equals(0, #items)
+    assert.equals(1, #notifications)
+    assert.equals(vim.log.levels.WARN, notifications[1].level)
+    assert.is_true(notifications[1].msg:find("check .gitignore/.ignore patterns or encoding", 1, true) ~= nil)
+  end)
 end)