Revision d88785e424aaf18aa3ca291c2299c599c000c6cb authored by Jeff King on 11 May 2016, 13:44:04 UTC, committed by Junio C Hamano on 11 May 2016, 21:03:14 UTC
Passing "-x" to a test script enables the shell's "set -x" tracing, which can help with tracking down the command that is causing a failure. Unfortunately, it can also _cause_ failures in some tests that redirect the stderr of a shell function. Inside the function the shell continues to respect "set -x", and the trace output is collected along with whatever stderr is generated normally by the function. You can see an example of this by running: ./t0040-parse-options.sh -x -i which will fail immediately in the first test, as it expects: test_must_fail some-cmd 2>output.err to leave output.err empty (but with "-x" it has our trace output). Unfortunately there isn't a portable or scalable solution to this. We could teach test_must_fail to disable "set -x", but that doesn't help any of the other functions or subshells. However, we can work around it by pointing the "set -x" output to our descriptor 4, which always points to the original stderr of the test script. Unfortunately this only works for bash, but it's better than nothing (and other shells will just ignore the BASH_XTRACEFD variable). The patch itself is a simple one-liner, but note the caveats in the accompanying comments. Automatic tests for our "-x" option may be a bit too meta (and a pain, because they are bash-specific), but I did confirm that it works correctly both with regular "-x" and with "--verbose-only=1". This works because the latter flips "set -x" off and on for particular tests (if it didn't, we would get tracing for all tests, as going to descriptor 4 effectively circumvents the verbose flag). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent 7654286
trace.c
/*
* GIT - The information manager from hell
*
* Copyright (C) 2000-2002 Michael R. Elkins <me@mutt.org>
* Copyright (C) 2002-2004 Oswald Buddenhagen <ossi@users.sf.net>
* Copyright (C) 2004 Theodore Y. Ts'o <tytso@mit.edu>
* Copyright (C) 2006 Mike McCormack
* Copyright (C) 2006 Christian Couder
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "cache.h"
#include "quote.h"
/* Get a trace file descriptor from "key" env variable. */
static int get_trace_fd(struct trace_key *key)
{
static struct trace_key trace_default = { "GIT_TRACE" };
const char *trace;
/* use default "GIT_TRACE" if NULL */
if (!key)
key = &trace_default;
/* don't open twice */
if (key->initialized)
return key->fd;
trace = getenv(key->key);
if (!trace || !strcmp(trace, "") ||
!strcmp(trace, "0") || !strcasecmp(trace, "false"))
key->fd = 0;
else if (!strcmp(trace, "1") || !strcasecmp(trace, "true"))
key->fd = STDERR_FILENO;
else if (strlen(trace) == 1 && isdigit(*trace))
key->fd = atoi(trace);
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",
trace, strerror(errno));
key->fd = STDERR_FILENO;
} else {
key->fd = fd;
key->need_close = 1;
}
} else {
fprintf(stderr, "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",
trace, key->key, key->key);
key->fd = STDERR_FILENO;
}
key->initialized = 1;
return key->fd;
}
void trace_disable(struct trace_key *key)
{
if (key->need_close)
close(key->fd);
key->fd = 0;
key->initialized = 1;
key->need_close = 0;
}
static const char err_msg[] = "Could not trace into fd given by "
"GIT_TRACE environment variable";
static int prepare_trace_line(const char *file, int line,
struct trace_key *key, struct strbuf *buf)
{
static struct trace_key trace_bare = TRACE_KEY_INIT(BARE);
struct timeval tv;
struct tm tm;
time_t secs;
if (!trace_want(key))
return 0;
set_try_to_free_routine(NULL); /* is never reset */
/* unit tests may want to disable additional trace output */
if (trace_want(&trace_bare))
return 1;
/* print current timestamp */
gettimeofday(&tv, NULL);
secs = tv.tv_sec;
localtime_r(&secs, &tm);
strbuf_addf(buf, "%02d:%02d:%02d.%06ld ", tm.tm_hour, tm.tm_min,
tm.tm_sec, (long) tv.tv_usec);
#ifdef HAVE_VARIADIC_MACROS
/* print file:line */
strbuf_addf(buf, "%s:%d ", file, line);
/* align trace output (column 40 catches most files names in git) */
while (buf->len < 40)
strbuf_addch(buf, ' ');
#endif
return 1;
}
static void print_trace_line(struct trace_key *key, struct strbuf *buf)
{
strbuf_complete_line(buf);
write_or_whine_pipe(get_trace_fd(key), buf->buf, buf->len, err_msg);
strbuf_release(buf);
}
static void trace_vprintf_fl(const char *file, int line, struct trace_key *key,
const char *format, va_list ap)
{
struct strbuf buf = STRBUF_INIT;
if (!prepare_trace_line(file, line, key, &buf))
return;
strbuf_vaddf(&buf, format, ap);
print_trace_line(key, &buf);
}
static void trace_argv_vprintf_fl(const char *file, int line,
const char **argv, const char *format,
va_list ap)
{
struct strbuf buf = STRBUF_INIT;
if (!prepare_trace_line(file, line, NULL, &buf))
return;
strbuf_vaddf(&buf, format, ap);
sq_quote_argv(&buf, argv, 0);
print_trace_line(NULL, &buf);
}
void trace_strbuf_fl(const char *file, int line, struct trace_key *key,
const struct strbuf *data)
{
struct strbuf buf = STRBUF_INIT;
if (!prepare_trace_line(file, line, key, &buf))
return;
strbuf_addbuf(&buf, data);
print_trace_line(key, &buf);
}
static struct trace_key trace_perf_key = TRACE_KEY_INIT(PERFORMANCE);
static void trace_performance_vprintf_fl(const char *file, int line,
uint64_t nanos, const char *format,
va_list ap)
{
struct strbuf buf = STRBUF_INIT;
if (!prepare_trace_line(file, line, &trace_perf_key, &buf))
return;
strbuf_addf(&buf, "performance: %.9f s", (double) nanos / 1000000000);
if (format && *format) {
strbuf_addstr(&buf, ": ");
strbuf_vaddf(&buf, format, ap);
}
print_trace_line(&trace_perf_key, &buf);
}
#ifndef HAVE_VARIADIC_MACROS
void trace_printf(const char *format, ...)
{
va_list ap;
va_start(ap, format);
trace_vprintf_fl(NULL, 0, NULL, format, ap);
va_end(ap);
}
void trace_printf_key(struct trace_key *key, const char *format, ...)
{
va_list ap;
va_start(ap, format);
trace_vprintf_fl(NULL, 0, key, format, ap);
va_end(ap);
}
void trace_argv_printf(const char **argv, const char *format, ...)
{
va_list ap;
va_start(ap, format);
trace_argv_vprintf_fl(NULL, 0, argv, format, ap);
va_end(ap);
}
void trace_strbuf(struct trace_key *key, const struct strbuf *data)
{
trace_strbuf_fl(NULL, 0, key, data);
}
void trace_performance(uint64_t nanos, const char *format, ...)
{
va_list ap;
va_start(ap, format);
trace_performance_vprintf_fl(NULL, 0, nanos, format, ap);
va_end(ap);
}
void trace_performance_since(uint64_t start, const char *format, ...)
{
va_list ap;
va_start(ap, format);
trace_performance_vprintf_fl(NULL, 0, getnanotime() - start,
format, ap);
va_end(ap);
}
#else
void trace_printf_key_fl(const char *file, int line, struct trace_key *key,
const char *format, ...)
{
va_list ap;
va_start(ap, format);
trace_vprintf_fl(file, line, key, format, ap);
va_end(ap);
}
void trace_argv_printf_fl(const char *file, int line, const char **argv,
const char *format, ...)
{
va_list ap;
va_start(ap, format);
trace_argv_vprintf_fl(file, line, argv, format, ap);
va_end(ap);
}
void trace_performance_fl(const char *file, int line, uint64_t nanos,
const char *format, ...)
{
va_list ap;
va_start(ap, format);
trace_performance_vprintf_fl(file, line, nanos, format, ap);
va_end(ap);
}
#endif /* HAVE_VARIADIC_MACROS */
static const char *quote_crnl(const char *path)
{
static char new_path[PATH_MAX];
const char *p2 = path;
char *p1 = new_path;
if (!path)
return NULL;
while (*p2) {
switch (*p2) {
case '\\': *p1++ = '\\'; *p1++ = '\\'; break;
case '\n': *p1++ = '\\'; *p1++ = 'n'; break;
case '\r': *p1++ = '\\'; *p1++ = 'r'; break;
default:
*p1++ = *p2;
}
p2++;
}
*p1 = '\0';
return new_path;
}
/* FIXME: move prefix to startup_info struct and get rid of this arg */
void trace_repo_setup(const char *prefix)
{
static struct trace_key key = TRACE_KEY_INIT(SETUP);
const char *git_work_tree;
char *cwd;
if (!trace_want(&key))
return;
cwd = xgetcwd();
if (!(git_work_tree = get_git_work_tree()))
git_work_tree = "(null)";
if (!prefix)
prefix = "(null)";
trace_printf_key(&key, "setup: git_dir: %s\n", quote_crnl(get_git_dir()));
trace_printf_key(&key, "setup: worktree: %s\n", quote_crnl(git_work_tree));
trace_printf_key(&key, "setup: cwd: %s\n", quote_crnl(cwd));
trace_printf_key(&key, "setup: prefix: %s\n", quote_crnl(prefix));
free(cwd);
}
int trace_want(struct trace_key *key)
{
return !!get_trace_fd(key);
}
#if defined(HAVE_CLOCK_GETTIME) && defined(HAVE_CLOCK_MONOTONIC)
static inline uint64_t highres_nanos(void)
{
struct timespec ts;
if (clock_gettime(CLOCK_MONOTONIC, &ts))
return 0;
return (uint64_t) ts.tv_sec * 1000000000 + ts.tv_nsec;
}
#elif defined (GIT_WINDOWS_NATIVE)
static inline uint64_t highres_nanos(void)
{
static uint64_t high_ns, scaled_low_ns;
static int scale;
LARGE_INTEGER cnt;
if (!scale) {
if (!QueryPerformanceFrequency(&cnt))
return 0;
/* high_ns = number of ns per cnt.HighPart */
high_ns = (1000000000LL << 32) / (uint64_t) cnt.QuadPart;
/*
* Number of ns per cnt.LowPart is 10^9 / frequency (or
* high_ns >> 32). For maximum precision, we scale this factor
* so that it just fits within 32 bit (i.e. won't overflow if
* multiplied with cnt.LowPart).
*/
scaled_low_ns = high_ns;
scale = 32;
while (scaled_low_ns >= 0x100000000LL) {
scaled_low_ns >>= 1;
scale--;
}
}
/* if QPF worked on initialization, we expect QPC to work as well */
QueryPerformanceCounter(&cnt);
return (high_ns * cnt.HighPart) +
((scaled_low_ns * cnt.LowPart) >> scale);
}
#else
# define highres_nanos() 0
#endif
static inline uint64_t gettimeofday_nanos(void)
{
struct timeval tv;
gettimeofday(&tv, NULL);
return (uint64_t) tv.tv_sec * 1000000000 + tv.tv_usec * 1000;
}
/*
* Returns nanoseconds since the epoch (01/01/1970), for performance tracing
* (i.e. favoring high precision over wall clock time accuracy).
*/
uint64_t getnanotime(void)
{
static uint64_t offset;
if (offset > 1) {
/* initialization succeeded, return offset + high res time */
return offset + highres_nanos();
} else if (offset == 1) {
/* initialization failed, fall back to gettimeofday */
return gettimeofday_nanos();
} else {
/* initialize offset if high resolution timer works */
uint64_t now = gettimeofday_nanos();
uint64_t highres = highres_nanos();
if (highres)
offset = now - highres;
else
offset = 1;
return now;
}
}
static uint64_t command_start_time;
static struct strbuf command_line = STRBUF_INIT;
static void print_command_performance_atexit(void)
{
trace_performance_since(command_start_time, "git command:%s",
command_line.buf);
}
void trace_command_performance(const char **argv)
{
if (!trace_want(&trace_perf_key))
return;
if (!command_start_time)
atexit(print_command_performance_atexit);
strbuf_reset(&command_line);
sq_quote_argv(&command_line, argv, 0);
command_start_time = getnanotime();
}
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