path: root/trace.c
diff options
authorJeff King <>2016-08-05 07:56:00 (GMT)
committerJunio C Hamano <>2016-08-05 16:27:34 (GMT)
commit38f460caa26e5dd06c3e874e30ea0ec5beb49b56 (patch)
treef085b0f544cd577c54b4c999d85b08e8658245aa /trace.c
parentc0222e762ef57c59fa793862618cfcdfef1cf3f8 (diff)
trace: use warning() for printing trace errors
Right now we just fprintf() straight to stderr, which can make the output hard to distinguish. It would be helpful to give it one of our usual prefixes like "error:", "warning:", etc. It doesn't make sense to use error() here, as the trace code is "optional" debugging code. If something goes wrong, we should warn the user, but saying "error" implies the actual git operation had a problem. So warning() is the only sane choice. Note that this does end up calling warn_routine() to do the formatting. This is probably a good thing, since they are clearly trying to hook messages before they make it to stderr. However, it also means that in theory somebody who tries to trace from their warn_routine() could cause a loop. This seems rather unlikely in practice (we've never even overridden the default warn_builtin routine before, and recent discussions to do so would just install a noop routine). Signed-off-by: Jeff King <> Signed-off-by: Junio C Hamano <>
Diffstat (limited to 'trace.c')
1 files changed, 5 insertions, 6 deletions
diff --git a/trace.c b/trace.c
index bdbe149..6a77e4d 100644
--- a/trace.c
+++ b/trace.c
@@ -61,9 +61,8 @@ static int get_trace_fd(struct trace_key *key)
else if (is_absolute_path(trace)) {
int fd = open(trace, O_WRONLY | O_APPEND | O_CREAT, 0666);
if (fd == -1) {
- fprintf(stderr,
- "Could not open '%s' for tracing: %s\n"
- "Defaulting to tracing on stderr...\n",
+ warning("Could not open '%s' for tracing: %s\n"
+ "Defaulting to tracing on stderr...",
trace, strerror(errno));
key->fd = STDERR_FILENO;
} else {
@@ -71,10 +70,10 @@ static int get_trace_fd(struct trace_key *key)
key->need_close = 1;
} else {
- fprintf(stderr, "What does '%s' for %s mean?\n"
+ warning("What does '%s' for %s mean?\n"
"If you want to trace into a file, then please set "
"%s to an absolute pathname (starting with /).\n"
- "Defaulting to tracing on stderr...\n",
+ "Defaulting to tracing on stderr...",
trace, key->key, key->key);
key->fd = STDERR_FILENO;
@@ -135,7 +134,7 @@ static int prepare_trace_line(const char *file, int line,
static void trace_write(struct trace_key *key, const void *buf, unsigned len)
if (write_in_full(get_trace_fd(key), buf, len) < 0)
- fprintf(stderr, "%s: write error (%s)\n", err_msg, strerror(errno));
+ warning("%s: write error (%s)", err_msg, strerror(errno));
void trace_verbatim(struct trace_key *key, const void *buf, unsigned len)