[PATCH] send-email: clarify missing subject error

["Harald Nordgren via GitGitGadget" <gitgitgadget@gmail.com>]

From: Harald Nordgren <haraldnordgren@gmail.com>

Explain the required Subject: prefix when a message file has no subject.
Terminate the error with a newline so Perl does not append its internal
source location.

Signed-off-by: Harald Nordgren <haraldnordgren@gmail.com>
---
    send-email: clarify missing subject error
    
    Explain the required Subject: prefix when a message file has no subject.
    Terminate the error with a newline so Perl does not append its internal
    source location.

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-2375%2FHaraldNordgren%2Ffix%2Fsend-email-subject-error-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-2375/HaraldNordgren/fix/send-email-subject-error-v1
Pull-Request: https://github.com/git/git/pull/2375

 git-send-email.perl   |  3 ++-
 t/t9001-send-email.sh | 15 +++++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/git-send-email.perl b/git-send-email.perl
index bb8ddd1eef..4d76d53c49 100755
--- a/git-send-email.perl
+++ b/git-send-email.perl
@@ -863,7 +863,8 @@ sub get_patch_subject {
 		return "GIT: $1\n";
 	}
 	close $fh;
-	die sprintf(__("No subject line in %s?"), $fn);
+	die sprintf(__("No subject line in %s. " .
+		"The first line must start with \"Subject: \"\n"), $fn);
 }
 
 if ($compose) {
diff --git a/t/t9001-send-email.sh b/t/t9001-send-email.sh
index e9d814a34a..a403dd278b 100755
--- a/t/t9001-send-email.sh
+++ b/t/t9001-send-email.sh
@@ -1422,6 +1422,21 @@ test_expect_success $PREREQ 'detects ambiguous reference/file conflict' '
 	test_grep disambiguate errors
 '
 
+test_expect_success $PREREQ 'missing subject omits Perl location' '
+	cat >no-subject.patch <<-\EOF &&
+	This is the body.
+	EOF
+	test_must_fail git send-email \
+		--dry-run \
+		--from="Example <nobody@example.com>" \
+		--to=nobody@example.com \
+		no-subject.patch 2>actual &&
+	cat >expect <<-\EOF &&
+	No subject line in no-subject.patch. The first line must start with "Subject: "
+	EOF
+	test_cmp expect actual
+'
+
 test_expect_success $PREREQ 'feed two files' '
 	rm -fr outdir &&
 	git format-patch -2 -o outdir &&

base-commit: 010afd3166ddc64c9863b1506f12cbcdda0d4ea1
-- 
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