fix(git_status): parse NUL-delimited git status output

Problem: `git status --porcelain` will wrap file paths with "special
characters" (eg `\n`, spaces) in double quotes which complicates
downstream parsing of results.

Furthermore, if a file path HAS a newline char, the existing approach
for getting results by splitting by `\n` is completely broken.

Solution: Switch to `git status -z`.
`-z` is more machine parse-able than plain `--porcelain` as git will no
longer treat paths with special characters specially, delimiting results
by NUL (the only non-valid character in unix paths) rather than LF while
keeping the benefit of `--porcelain` (stable across git versions and
user config).
Adds support for this in `async_oneshot_finder`/`LinesPipe` via a
new `split_char` option.

Author: jamestrew

lua/telescope/_.lua

@@ -147,10 +147,9 @@ function LinesPipe:read()
   return read_rx()
 end
 
-function LinesPipe:iter(schedule)
-  if schedule == nil then
-    schedule = true
-  end
+function LinesPipe:iter(schedule, opts)
+  schedule = vim.F.if_nil(schedule, true)
+  local split_char = vim.F.if_nil(opts and opts.split_char, "\n")
 
   local text = nil
   local index = nil
@@ -167,8 +166,7 @@ function LinesPipe:iter(schedule)
     return (previous or "") .. read
   end
 
-  local next_value = nil
-  next_value = function()
+  local function next_value()
     if schedule then
       async.util.scheduler()
     end
@@ -178,7 +176,7 @@ function LinesPipe:iter(schedule)
     end
 
     local start = index
-    index = string.find(text, "\n", index, true)
+    index = string.find(text, split_char, index, true)
 
     if index == nil then
       text = get_next_text(string.sub(text, start or 1))

lua/telescope/builtin/__git.lua

@@ -371,14 +371,15 @@ git.status = function(opts)
     return
   end
 
-  local args = { "status", "--porcelain=v1", "--", "." }
+  local args = { "status", "-z", "--", "." }
 
   local gen_new_finder = function()
     if vim.F.if_nil(opts.expand_dir, true) then
       table.insert(args, #args - 1, "-uall")
     end
     local git_cmd = git_command(args, opts)
     opts.entry_maker = vim.F.if_nil(opts.entry_maker, make_entry.gen_from_git_status(opts))
+    opts.split_char = "\0"
     return finders.new_oneshot_job(git_cmd, opts)
   end
 

lua/telescope/finders.lua

@@ -199,6 +199,7 @@ finders.new_oneshot_job = function(command_list, opts)
 
     cwd = opts.cwd,
     maximum_results = opts.maximum_results,
+    split_char = opts.split_char,
 
     fn_command = function()
       return {

lua/telescope/finders/async_oneshot_finder.lua

@@ -63,7 +63,7 @@ return function(opts)
             process_result(v)
           end
         end
-        for line in stdout:iter(false) do
+        for line in stdout:iter(false, { split_char = opts.split_char }) do
           num_results = num_results + 1
 
           if num_results % await_count then