Re: [PATCH 2/2] bugfix: git diff --quiet -w never returns with exit status 1

3 messages, 2 authors, 2016-06-15 · open the first message on its own page

Re: [PATCH 2/2] bugfix: git diff --quiet -w never returns with exit status 1

From: Junio C Hamano <hidden>
Date: 2016-06-15 22:48:17

Larry D'Anna [off-list ref] writes:
Rationale: diff_flush_patch expects to write its output to options->file.
Adding a "silence" flag to diff_flush_patch and everything it calls would be
more invasive.
I would agree that the logic to redirect the output to nowhere may be the
easiest way out, but because the reason anybody sane would want to give -q
is to say "I don't care what the actual changes are, but I want to know if
there is any real quick" (otherwise the call would be "diff -w >/dev/null"),
shouldn't we at least be exiting the loop early when we see any difference?
quoted hunk
Signed-off-by: Larry D'Anna <redacted>
---
 diff.c |   20 ++++++++++++++++++++
 1 files changed, 20 insertions(+), 0 deletions(-)
diff --git a/diff.c b/diff.c
index 68def6c..ff00816 100644
--- a/diff.c
+++ b/diff.c
@@ -3522,6 +3522,26 @@ void diff_flush(struct diff_options *options)
 		separator++;
 	}
 
+	if (output_format & DIFF_FORMAT_NO_OUTPUT &&
+	    DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
+	    DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
+		/* run diff_flush_patch for the exit status */
+		/* setting options->file to /dev/null should be safe, becaue we
+		   aren't supposed to produce any output anyways */
Style?
+		static FILE *devnull = NULL;
Would this cause one file descriptor to leak?  Do we care?
+		if(!devnull) {
Style?	if (!devnull)
+			devnull = fopen("/dev/null", "w");
+			if (!devnull)
+				die_errno("Could not open /dev/null");
+		}
+		options->file = devnull;
Would this cause the original "options->file" leak?  Do we care?
+		for (i = 0; i < q->nr; i++) {
+			struct diff_filepair *p = q->queue[i];
+			if (check_pair_status(p))
+				diff_flush_patch(p, options);
+		}
+	}
+
 	if (output_format & DIFF_FORMAT_PATCH) {
 		if (separator) {
 			putc(options->line_termination, options->file);
-- 
1.7.0.rc2.40.g7d8aa

Re: [PATCH 2/2] bugfix: git diff --quiet -w never returns with exit status 1

From: Larry D'Anna <hidden>
Date: 2016-06-15 22:48:17

* Junio C Hamano (gitster@pobox.com) [100216 00:42]:
Larry D'Anna [off-list ref] writes:
quoted
Rationale: diff_flush_patch expects to write its output to options->file.
Adding a "silence" flag to diff_flush_patch and everything it calls would be
more invasive.
I would agree that the logic to redirect the output to nowhere may be the
easiest way out, but because the reason anybody sane would want to give -q
is to say "I don't care what the actual changes are, but I want to know if
there is any real quick" (otherwise the call would be "diff -w >/dev/null"),
shouldn't we at least be exiting the loop early when we see any difference?
quoted
Signed-off-by: Larry D'Anna <redacted>
---
 diff.c |   20 ++++++++++++++++++++
 1 files changed, 20 insertions(+), 0 deletions(-)
diff --git a/diff.c b/diff.c
index 68def6c..ff00816 100644
--- a/diff.c
+++ b/diff.c
@@ -3522,6 +3522,26 @@ void diff_flush(struct diff_options *options)
 		separator++;
 	}
 
+	if (output_format & DIFF_FORMAT_NO_OUTPUT &&
+	    DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
+	    DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
+		/* run diff_flush_patch for the exit status */
+		/* setting options->file to /dev/null should be safe, becaue we
+		   aren't supposed to produce any output anyways */
Style?
quoted
+		static FILE *devnull = NULL;
Would this cause one file descriptor to leak?  Do we care?
Originally I thought it would be best to just let one leak, because I didn't
know how much longer it would need to stick around.  I didn't notice it's being
closed anyway a few lines down.

quoted
+		if(!devnull) {
Style?	if (!devnull)
quoted
+			devnull = fopen("/dev/null", "w");
+			if (!devnull)
+				die_errno("Could not open /dev/null");
+		}
+		options->file = devnull;
Would this cause the original "options->file" leak?  Do we care?
oops.
quoted
+		for (i = 0; i < q->nr; i++) {
+			struct diff_filepair *p = q->queue[i];
+			if (check_pair_status(p))
+				diff_flush_patch(p, options);
+		}
+	}
+
 	if (output_format & DIFF_FORMAT_PATCH) {
 		if (separator) {
 			putc(options->line_termination, options->file);
-- 
1.7.0.rc2.40.g7d8aa

[PATCH 2/2] bugfix: git diff --quiet -w never returns with exit status 1

From: Larry D'Anna <hidden>
Date: 2016-06-15 22:48:17

The problem: -w causes the flag DIFF_FROM_CONTENTS to be set, which causes
diff_flush to set the flag HAS_CHANGES based on options->found_changes, which is
set by diff_flush_patch (if there were any changes).  However, --quiet causes
diff_flush to never call diff_flush_patch, so options->found_changes is always 0.

The solution: In this situation, call diff_flush_patch with options->file set to
/dev/null.

Rationale: diff_flush_patch expects to write its output to options->file.
Adding a "silence" flag to diff_flush_patch and everything it calls would be
more invasive.

Signed-off-by: Larry D'Anna <redacted>
---
 diff.c |   23 +++++++++++++++++++++++
 1 files changed, 23 insertions(+), 0 deletions(-)
diff --git a/diff.c b/diff.c
index 68def6c..2984c41 100644
--- a/diff.c
+++ b/diff.c
@@ -3522,6 +3522,29 @@ void diff_flush(struct diff_options *options)
 		separator++;
 	}
 
+	if (output_format & DIFF_FORMAT_NO_OUTPUT &&
+	    DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
+	    DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
+		/*
+		 * run diff_flush_patch for the exit status.
+		 * setting options->file to /dev/null should be safe, becaue we
+		 * aren't supposed to produce any output anyways
+		 */
+		if (options->close_file)
+			fclose(options->file);
+		options->file = fopen("/dev/null", "w");
+		if (!options->file)
+			die_errno("Could not open /dev/null");
+		options->close_file = 1;
+		for (i = 0; i < q->nr; i++) {
+			struct diff_filepair *p = q->queue[i];
+			if (check_pair_status(p))
+				diff_flush_patch(p, options);
+			if (options->found_changes)
+				break;
+		}
+	}
+
 	if (output_format & DIFF_FORMAT_PATCH) {
 		if (separator) {
 			putc(options->line_termination, options->file);
-- 
1.7.0.rc2.40.g7d8aa
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