bug#22354: Test failure when running distcheck from out-of-tree build

[Ludovic Courtès]

address@hidden (Taylan Ulrich "Bayırlı/Kammer") skribis:

> address@hidden (Ludovic Courtès) writes:
>
>> address@hidden (Taylan Ulrich "Bayırlı/Kammer") skribis:

>>>>> ./configure: ./config.status: 
>>>>> /home/taylan/src/guix/build/guix-0.9.1/_build/sub/test-tmp/store/d41iyl2gyk0r:
>>>>>  bad interpreter: No such file or directory

[...]

>>> Hmm, that commit didn't fix the issue.
>>
>> You mean it doesn’t error out directly upon ‘make check’?  Could you
>> run “grep length …/_build/config.log”?
>
> Yes, it still goes through the tests and fails at guix-environment.sh
> with the same error.  I repeated all steps from a new clone of master.
>
> address@hidden:~/src/guix/build$ grep length guix-0.9.1/_build/sub/config.log
> configure:6946: checking the length of the installed socket file name
> configure:6969: checking the length of the socket file name used in tests
> configure:6980: checking the length of a typical hash bang line
> configure:6992: checking the length of a hash bang line used in tests
> ac_cv_guix_hash_bang_length=73
> ac_cv_guix_socket_file_name_length=74
> ac_cv_guix_test_hash_bang_length=127
> ac_cv_guix_test_socket_file_name_length=90

Arff, I see.  I’ve change LINUX_HASH_BANG_LIMIT in guix.m4 to 127
instead of 128 to account for the trailing zero.

This time it should detect the problem early.

>>> Only the error message is broken.
>>
>> Would be interesting to see which is the piece of software that has an
>> even lower limit here.
>
> For what it's worth, I confirmed that on my system (Debian 8), using
> /bin/bash (in case it should be relevant):
>
> - the hash bang limit of a called script is 127 characters, and
>
> - when I pass the limit, I get an error message where the path is
>   truncated to 77 characters.

The “bad interpreter” message comes from Bash, in execute_cmd.c.

However, that file does this:

--8<---------------cut here---------------start------------->8---
  char sample[80];

[…]

#if defined (HAVE_HASH_BANG_EXEC)
          READ_SAMPLE_BUF (command, sample, sample_len);
          sample[sample_len - 1] = '\0';
          if (sample_len > 2 && sample[0] == '#' && sample[1] == '!')
            {
              char *interp;
              int ilen;

              interp = getinterp (sample, sample_len, (int *)NULL);
--8<---------------cut here---------------end--------------->8---

where READ_SAMPLE_BUF is:

--8<---------------cut here---------------start------------->8---
#define READ_SAMPLE_BUF(file, buf, len) \
  do \
    { \
      fd = open(file, O_RDONLY); \
      if (fd >= 0) \
        { \
          len = read (fd, buf, 80); \
          close (fd); \
        } \
      else \
        len = -1; \
    } \
  while (0)
--8<---------------cut here---------------end--------------->8---

Now we know.  :-)

Ludo’.