t/lib-git-daemon: record daemon log

When we start git-daemon for our tests, we send its stderr
log stream to a named pipe. We synchronously read the first
line to make sure that the daemon started, and then dump the
rest to descriptor 4. This is handy for debugging test
output with "--verbose", but the tests themselves can't
access the log data.

Let's dump the log into a file, as well, so that future
tests can check the log. There are a few subtleties worth
calling out here:

- we'll continue to send output to descriptor 4 for
viewing/debugging, which would imply swapping out "cat"
for "tee". But we want to ensure that there's no
buffering, and "tee" doesn't have a standard way to
ask for that. So we'll use a shell loop around "read"
and "printf" instead. That ensures that after a request
has been served, the matching log entries will have made
it to the file.

- the existing first-line shell loop used read/echo. We'll
switch to consistently using "read -r" and "printf" to
relay data as faithfully as possible.

- we open the logfile for append, rather than just output.
That makes it OK for tests to truncate the logfile
without restarting the daemon (the OS will atomically
seek to the end of the file when outputting each line).
That allows tests to look at the log without worrying
about pollution from earlier tests.

Helped-by: Lucas Werkmeister <mail@lucaswerkmeister.de>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/t/lib-git-daemon.sh b/t/lib-git-daemon.sh
index 987d40680b4d23f9053c623529eaafa88da04616..9612cccefb1c9dd37e61857a88ea92d86ddf854d 100644 (file)
--- a/t/lib-git-daemon.sh
+++ b/t/lib-git-daemon.sh
@@ -53,11 +53,19 @@ start_git_daemon() {
                "$@" "$GIT_DAEMON_DOCUMENT_ROOT_PATH" \
                >&3 2>git_daemon_output &
        GIT_DAEMON_PID=$!
+       >daemon.log
        {
-               read line <&7
-               echo >&4 "$line"
-               cat <&7 >&4 &
-       } 7<git_daemon_output &&
+               read -r line <&7
+               printf "%s\n" "$line"
+               printf >&4 "%s\n" "$line"
+               (
+                       while read -r line <&7
+                       do
+                               printf "%s\n" "$line"
+                               printf >&4 "%s\n" "$line"
+                       done
+               ) &
+       } 7<git_daemon_output >>"$TRASH_DIRECTORY/daemon.log" &&
 
        # Check expected output
        if test x"$(expr "$line" : "\[[0-9]*\] \(.*\)")" != x"Ready to rumble"