[PATCH 1/3] log-tree: take ownership of pointer

[Kristoffer Haugsbakk <code@khaugsbakk.name>]

The MIME header handling started using string buffers in
d50b69b868d (log_write_email_headers: use strbufs, 2018-05-18). The
subject buffer is given to `extra_headers` without that variable taking
ownership; the commit “punts on that ownership” (in general, not just
for this buffer).

In an upcoming commit we will first assign `extra_headers` to the owned
pointer from another `strbuf`. In turn we need this variable to always
contain an owned pointer so that we can free it in the calling
function.

Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name>
---
 log-tree.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/log-tree.c b/log-tree.c
index 337b9334cdb..2eabd19962b 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -519,7 +519,7 @@ void log_write_email_headers(struct rev_info *opt, struct commit *commit,
 			 extra_headers ? extra_headers : "",
 			 mime_boundary_leader, opt->mime_boundary,
 			 mime_boundary_leader, opt->mime_boundary);
-		extra_headers = subject_buffer.buf;
+		extra_headers = strbuf_detach(&subject_buffer, NULL);
 
 		if (opt->numbered_files)
 			strbuf_addf(&filename, "%d", opt->nr);
-- 
2.44.0.169.gd259cac85a8