[PATCH v4] transport-helper: report errors properly

[Felipe Contreras <felipe.contreras@gmail.com>]

If a push fails because the remote-helper died (with fast-export), the
user won't see any error message. So let's add one.

At the same time lets add tests to ensure this error is reported, and
while we are at it, check the error from fast-import

Suggested-by: Jeff King <peff@peff.net>
Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
---
 git-remote-testgit        | 13 +++++++++++++
 t/t5801-remote-helpers.sh | 21 +++++++++++++++++++++
 transport-helper.c        |  2 +-
 3 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/git-remote-testgit b/git-remote-testgit
index b395c8d..2eb7889 100755
--- a/git-remote-testgit
+++ b/git-remote-testgit
@@ -61,12 +61,25 @@ do
 			echo "feature import-marks=$gitmarks"
 			echo "feature export-marks=$gitmarks"
 		fi
+
+		if test -n "$GIT_REMOTE_TESTGIT_FAILURE"
+		then
+			echo "feature done"
+			exit 1
+		fi
+
 		echo "feature done"
 		git fast-export "${testgitmarks_args[@]}" $refs |
 		sed -e "s#refs/heads/#${prefix}/heads/#g"
 		echo "done"
 		;;
 	export)
+		if test -n "$GIT_REMOTE_TESTGIT_FAILURE"
+		then
+			sleep 1 # don't let fast-export get SIGPIPE
+			exit 1
+		fi
+
 		before=$(git for-each-ref --format='%(refname) %(objectname)')
 
 		git fast-import "${testgitmarks_args[@]}" --quiet
diff --git a/t/t5801-remote-helpers.sh b/t/t5801-remote-helpers.sh
index f387027..2dfcf64 100755
--- a/t/t5801-remote-helpers.sh
+++ b/t/t5801-remote-helpers.sh
@@ -166,4 +166,25 @@ test_expect_success 'push ref with existing object' '
 	compare_refs local dup server dup
 '
 
+test_expect_success 'proper failure checks for fetching' '
+	(GIT_REMOTE_TESTGIT_FAILURE=1 &&
+	export GIT_REMOTE_TESTGIT_FAILURE &&
+	cd local &&
+	test_must_fail git fetch 2> error &&
+	cat error &&
+	grep -q "Error while running fast-import" error
+	)
+'
+
+# We sleep to give fast-export a chance to catch the SIGPIPE
+test_expect_success 'proper failure checks for pushing' '
+	(GIT_REMOTE_TESTGIT_FAILURE=1 &&
+	export GIT_REMOTE_TESTGIT_FAILURE &&
+	cd local &&
+	test_must_fail git push --all 2> error &&
+	cat error &&
+	grep -q "Reading from remote helper failed" error
+	)
+'
+
 test_done
diff --git a/transport-helper.c b/transport-helper.c
index cb3ef7d..96081cc 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -54,7 +54,7 @@ static int recvline_fh(FILE *helper, struct strbuf *buffer)
 	if (strbuf_getline(buffer, helper, '\n') == EOF) {
 		if (debug)
 			fprintf(stderr, "Debug: Remote helper quit.\n");
-		exit(128);
+		die("Reading from remote helper failed");
 	}
 
 	if (debug)
-- 
1.8.2