[PATCH v5] send-email: prompt-dependent exit codes

[Oswald Buddenhagen <oswald.buddenhagen@gmx.de>]

It seems very likely that most scripted callers would want to know when
(some) mails were interactively requested to be not sent, so indicate
this situation with a non-zero exit code. We use 10/11, because these
seem sufficiently distinct from "regular" error codes one would expect.

This is technically a backwards-incompatible behavior change, and
therefore would be safer to make opt-in. However, it is much easier to
imagine that a scripting user simply didn't consider the possibility of
an interactive cancellation, than that they really meant to ignore it.
Also, the damage resulting from reporting the situation too eagerly is
expected to be trivial, while the damage resulting from callers failing
to opt-in (which is obviously the status quo, and is likely to persist
in most cases) is potentially at least somewhat serious. This means that
making it opt-in has an opportunity cost, and I think the trade-off
favors making the new behavior unconditional.

For interactive calls from the command line, interactive cancellation is
arguably not unexpected, but a human user will be able to interpret the
somewhat unusual exit code in light of their immediately preceding
interactions just fine.

Signed-off-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>

---
Proposed content for RelNotes:

 * "git send-email" now reports interactive cancellation via a distinct
   non-zero exit status. Callers which do not consider this situation an
   error need to be adjusted.

---
v5:
- fix whitespace in tests' redirections
- tweak commit message some more
- tweak manual (notably, it now says "1" instead of "one", which is
  linguistically incorrect, but imo less confusing)
- fix inaccuracy in a comment in do_exit()
v4:
- add tests (which also cover the partial confirmation behavior in the
  first place)
- add docu
- rework commit message again
v3:
- use a tally instead of flags after all, as my seemingly simple idea
  apparently requires lots of thinking to grasp fully
- correct exit code when zero messages are to be sent. this cannot
  actually happen, as it induces an exit via usage() earlier on.
- unfold nested ternary to save junio's sanity (who proved his point by
  unfolding it slightly incorrectly)
- expand commit message
v2:
- fix do_quit() not resetting $sent_all

Cc: Junio C Hamano <gitster@pobox.com>
Cc: Phillip Wood <phillip.wood123@gmail.com>
---
 Documentation/git-send-email.txt |  9 ++++++++
 git-send-email.perl              | 32 ++++++++++++++++++++++++----
 t/t9001-send-email.sh            | 36 ++++++++++++++++++++++++++++++++
 3 files changed, 73 insertions(+), 4 deletions(-)

diff --git a/Documentation/git-send-email.txt b/Documentation/git-send-email.txt
index 492a82323d..766c190ef0 100644
--- a/Documentation/git-send-email.txt
+++ b/Documentation/git-send-email.txt
@@ -480,6 +480,15 @@ include::includes/cmd-config-section-all.txt[]
 
 include::config/sendemail.txt[]
 
+
+EXIT STATUS
+-----------
+
+Zero is returned when all specified patches were sent, while 1 is returned
+when an error occurs. 10 is returned if the user interactively skips sending
+only some patches, and 11 if they skip all patches.
+
+
 EXAMPLES
 --------
 Use gmail as the smtp server
diff --git a/git-send-email.perl b/git-send-email.perl
index affbb88509..2c62de07bc 100755
--- a/git-send-email.perl
+++ b/git-send-email.perl
@@ -256,6 +256,26 @@ sub system_or_die {
 	die $msg if $msg;
 }
 
+my $sent_files = 0;
+
+sub do_exit {
+	if ($sent_files == @files) {
+		# All specified messages were sent
+		exit(0);
+	} elsif ($sent_files) {
+		# At least some messages were sent
+		exit(10);
+	} else {
+		# User skipped all messages or quit before sending the first one
+		exit(11);
+	}
+}
+
+sub do_quit {
+	cleanup_compose_files();
+	do_exit();
+}
+
 sub do_edit {
 	if (!defined($editor)) {
 		$editor = Git::command_oneline('var', 'GIT_EDITOR');
@@ -1195,8 +1215,7 @@ sub validate_address {
 		if (/^d/i) {
 			return undef;
 		} elsif (/^q/i) {
-			cleanup_compose_files();
-			exit(0);
+			do_quit();
 		}
 		$address = ask("$to_whom ",
 			default => "",
@@ -1619,8 +1638,7 @@ sub send_message {
 		} elsif (/^e/i) {
 			return -1;
 		} elsif (/^q/i) {
-			cleanup_compose_files();
-			exit(0);
+			do_quit();
 		} elsif (/^a/i) {
 			$confirm = 'never';
 		}
@@ -2001,6 +2019,10 @@ sub process_file {
 		return 0;
 	}
 
+	if ($message_was_sent) {
+		$sent_files++;
+	}
+
 	# set up for the next message
 	if ($thread) {
 		if ($message_was_sent &&
@@ -2278,3 +2300,5 @@ sub body_or_subject_has_nonascii {
 	}
 	return 0;
 }
+
+do_exit();
diff --git a/t/t9001-send-email.sh b/t/t9001-send-email.sh
index 48bf0af2ee..64f9c7c154 100755
--- a/t/t9001-send-email.sh
+++ b/t/t9001-send-email.sh
@@ -1187,6 +1187,42 @@ test_expect_success $PREREQ 'confirm does not loop forever' '
 			$patches
 '
 
+test_confirm_many () {
+	clean_fake_sendmail
+	GIT_SEND_EMAIL_NOTTY=1 \
+	git send-email \
+		--confirm=auto \
+		--from="Example <nobody@example.com>" \
+		--to=nobody@example.com \
+		--smtp-server="$(pwd)/fake.sendmail" \
+		-2 <replies
+	echo $? >exit_sts
+	test_cmp expected_sts exit_sts || return 1
+	ls commandline* 2>/dev/null | wc -l >num_mails
+	test_cmp expected_num num_mails || return 1
+}
+
+test_expect_success $PREREQ 'interactively skip none' '
+	(echo y && echo y) >replies &&
+	echo 0 >expected_sts &&
+	echo 2 >expected_num &&
+	test_confirm_many
+'
+
+test_expect_success $PREREQ 'interactively skip some' '
+	(echo n && echo y) >replies &&
+	echo 10 >expected_sts &&
+	echo 1 >expected_num &&
+	test_confirm_many
+'
+
+test_expect_success $PREREQ 'interactively skip all' '
+	(echo n && echo n) >replies &&
+	echo 11 >expected_sts &&
+	echo 0 >expected_num &&
+	test_confirm_many
+'
+
 test_expect_success $PREREQ 'utf8 Cc is rfc2047 encoded' '
 	clean_fake_sendmail &&
 	rm -fr outdir &&
-- 
2.40.0.152.g15d061e6df