The progress.c code makes a hard assumption that only one progress bar be active at a time (see [1] for a bug where this wasn't the case), but nothing has asserted that that's the case. Let's add a BUG() that'll trigger if two progress bars are active at the same time. There's an alternate test-only approach to doing the same thing[2], but by doing this for all progress bars we'll have a canary to check if we have any unexpected interaction between the "sig_atomic_t progress_update" variable and this global struct. I am then planning on using this scaffolding in the future to fix a limitation in the progress output, namely the current limitation of the progress.c bar code that any update must pro-actively go through the likes of display_progress(). If we e.g. hang forever before the first display_progress(), or in the middle of a loop that would call display_progress() the user will only see either no output, or output frozen at the last display_progress() that would have done an update (e.g. in cases where progress_update was "1" due to an earlier signal). This change does not fix that, but sets up the structure for solving that and other related problems by juggling this "global_progress" struct. Later changes will make more use of the "global_progress" than only using it for these assertions. 1. 6f9d5f2fda1 (commit-graph: fix progress of reachable commits, 2020-07-09) 2. https://lore.kernel.org/git/20210620200303.2328957-3-szeder.dev@xxxxxxxxx Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> --- progress.c | 17 +++++++++++++---- t/t0500-progress-display.sh | 11 +++++++++++ 2 files changed, 24 insertions(+), 4 deletions(-) diff --git a/progress.c b/progress.c index 912edd4c818..e1b50ef7882 100644 --- a/progress.c +++ b/progress.c @@ -45,6 +45,7 @@ struct progress { }; static volatile sig_atomic_t progress_update; +static struct progress *global_progress; /* * These are only intended for testing the progress output, i.e. exclusively @@ -220,11 +221,15 @@ void progress_test_force_update(void) progress_interval(SIGALRM); } -static void set_progress_signal(void) +static void set_progress_signal(struct progress *progress) { struct sigaction sa; struct itimerval v; + if (global_progress) + BUG("should have no global_progress in set_progress_signal()"); + global_progress = progress; + if (progress_testing) return; @@ -242,10 +247,14 @@ static void set_progress_signal(void) setitimer(ITIMER_REAL, &v, NULL); } -static void clear_progress_signal(void) +static void clear_progress_signal(struct progress *progress) { struct itimerval v = {{0,},}; + if (!global_progress) + BUG("should have a global_progress in clear_progress_signal()"); + global_progress = NULL; + if (progress_testing) return; @@ -268,7 +277,7 @@ static struct progress *start_progress_delay(const char *title, uint64_t total, strbuf_init(&progress->counters_sb, 0); progress->title_len = utf8_strwidth(title); progress->split = 0; - set_progress_signal(); + set_progress_signal(progress); trace2_region_enter("progress", title, the_repository); return progress; } @@ -342,7 +351,7 @@ void stop_progress_msg(struct progress **p_progress, const char *msg) display(progress, progress->last_value, buf); free(buf); } - clear_progress_signal(); + clear_progress_signal(progress); strbuf_release(&progress->counters_sb); if (progress->throughput) strbuf_release(&progress->throughput->display); diff --git a/t/t0500-progress-display.sh b/t/t0500-progress-display.sh index 66c1989b176..476a31222a3 100755 --- a/t/t0500-progress-display.sh +++ b/t/t0500-progress-display.sh @@ -361,4 +361,15 @@ test_expect_success 'progress generates traces: stop without start' ' ! grep region_leave.*progress trace-stop.event ' +test_expect_success 'BUG: start two concurrent progress bars' ' + cat >in <<-\EOF && + start 0 one + start 0 two + EOF + + test_must_fail test-tool progress \ + <in 2>stderr && + grep -E "^BUG: .*: should have no global_progress in set_progress_signal\(\)$" stderr +' + test_done -- 2.32.0.599.g3967b4fa4ac
