Merge branch 'jk/run-command-capture'

The run-command interface was easy to abuse and make a pipe for us
to read from the process, wait for the process to finish and then
attempt to read its output, which is a pattern that lead to a
deadlock.  Fix such uses by introducing a helper to do this
correctly (i.e. we need to read first and then wait the process to
finish) and also add code to prevent such abuse in the run-command
helper.

* jk/run-command-capture:
  run-command: forbid using run_command with piped output
  trailer: use capture_command
  submodule: use capture_command
  wt-status: use capture_command
  run-command: introduce capture_command helper
  wt_status: fix signedness mismatch in strbuf_read call
  wt-status: don't flush before running "submodule status"

1 files changed, 1 insertions, 3 deletions

diff --git a/submodule.c b/submodule.c
index d37d400b2..c0e6c81fc 100644
--- a/submodule.c
+++ b/submodule.c
@@ -576,12 +576,10 @@ static int is_submodule_commit_present(const char *path, unsigned char sha1[20])
 		cp.env = local_repo_env;
 		cp.git_cmd = 1;
 		cp.no_stdin = 1;
-		cp.out = -1;
 		cp.dir = path;
-		if (!run_command(&cp) && !strbuf_read(&buf, cp.out, 1024))
+		if (!capture_command(&cp, &buf, 1024) && !buf.len)
 			is_present = 1;
 
-		close(cp.out);
 		strbuf_release(&buf);
 	}
 	return is_present;