Our team researches on consistent update of Git during evolution. And we have figured out several spots that may be missed. 


By mining historical patches, we suggest that invokes of error(..., strerror(errno)) should be replaced with that of error_errno(). One example for recommendation and corresponding patch are listed as follows. 

One example of missed spot:

1  int cmd_fetch__tool(int argc, const char **argv, const char 
  *prefix)
2  {
....
31  filename = git_path_fetch_head();
32  fp = fopen(filename, "a");
33  if (!fp)
34  return error("cannot open %s: %s", filename, strerror(errno));
....
  }

One example of historical patch:
1  if (!strcmp(*paths, "-"))
2  in = stdin;
3  else
4  in = fopen(*paths, "r");
5
6  if (!in)
7  -  return error(_("could not open '%s' for reading: %s"),
8  -     *paths, strerror(errno));
9  +  return error_errno(_("could not open '%s' for reading"),
10 +     *paths);
11
12 mail = mkpath("%s/%0*d", state->dir, state->prec, i + 1);
13
14 out = fopen(mail, "w");
15 if (!out)
16 - return error(_("could not open '%s' for writing: %s"),
17 - mail, strerror(errno));
18 + return error_errno(_("could not open '%s' for writing"),
19 + mail);
20
21 ret = fn(out, in, keep_cr);
22
23 fclose(out);
24 fclose(in);
25
More recommendations and supporting patches are saved in attachments. It is so kind of you to reply me about the correctness of our suggestions. And thank you for your reading.