fix: injected formatter hangs on empty file

2 files changed, 16 insertions, 3 deletions

diff --git a/lua/conform/formatters/injected.lua b/lua/conform/formatters/injected.lua
index 4990e05..bc4016c 100644
--- a/lua/conform/formatters/injected.lua
+++ b/lua/conform/formatters/injected.lua
@@ -53,6 +53,7 @@ return {
   end,
   format = function(ctx, lines, callback)
     local conform = require("conform")
+    local log = require("conform.log")
     local util = require("conform.util")
     local ok, parser = pcall(vim.treesitter.get_parser, ctx.buf)
     if not ok then
@@ -78,6 +79,7 @@ return {
     table.sort(regions, function(a, b)
       return a[2] > b[2]
     end)
+    log.trace("Injected formatter regions %s", regions)
 
     local replacements = {}
     local format_error = nil
@@ -124,6 +126,8 @@ return {
         local formatter_names = conform.formatters_by_ft[lang]
         local format_opts = { async = true, bufnr = ctx.buf, quiet = true }
         local idx = num_format
+        log.debug("Injected format %s:%d:%d: %s", lang, start_lnum, end_lnum, formatter_names)
+        log.trace("Injected format lines %s", input_lines)
         conform.format_lines(formatter_names, input_lines, format_opts, function(err, new_lines)
           -- Preserve indentation in case the code block is indented
           apply_indent(input_lines, new_lines)
@@ -131,5 +135,8 @@ return {
         end)
       end
     end
+    if num_format == 0 then
+      apply_format_results()
+    end
   end,
 }
diff --git a/lua/conform/runner.lua b/lua/conform/runner.lua
index a8ea203..7530008 100644
--- a/lua/conform/runner.lua
+++ b/lua/conform/runner.lua
@@ -257,9 +257,17 @@ local last_run_errored = {}
 ---@param callback fun(err?: conform.Error, output?: string[])
 ---@return integer? job_id
 local function run_formatter(bufnr, formatter, config, ctx, input_lines, callback)
+  log.info("Run %s on %s", formatter.name, vim.api.nvim_buf_get_name(bufnr))
+  log.trace("Input lines: %s", input_lines)
   if config.format then
     ---@cast config conform.LuaFormatterConfig
-    config.format(ctx, input_lines, callback)
+    local ok, err = pcall(config.format, ctx, input_lines, callback)
+    if not ok then
+      callback({
+        code = M.ERROR_CODE.RUNTIME,
+        message = string.format("Formatter '%s' error: %s", formatter.name, err),
+      })
+    end
     return
   end
   ---@cast config conform.JobFormatterConfig
@@ -283,14 +291,12 @@ local function run_formatter(bufnr, formatter, config, ctx, input_lines, callbac
     end
   end)
 
-  log.info("Run %s on %s", formatter.name, vim.api.nvim_buf_get_name(bufnr))
   local buffer_text
   -- If the buffer has a newline at the end, make sure we include that in the input to the formatter
   local add_extra_newline = vim.bo[bufnr].eol
   if add_extra_newline then
     table.insert(input_lines, "")
   end
-  log.trace("Input lines: %s", input_lines)
   buffer_text = table.concat(input_lines, "\n")
   if add_extra_newline then
     table.remove(input_lines)