Merge branch 'fc/transport-helper-error-reporting'

Update transport helper to report errors and maintain ref hierarchy
used to keep track of remote helper state better.

* fc/transport-helper-error-reporting:
  transport-helper: fix remote helper namespace regression
  test: remote-helper: add missing and
  t5801: "VAR=VAL shell_func args" is forbidden
  transport-helper: update remote helper namespace
  transport-helper: trivial code shuffle
  transport-helper: warn when refspec is not used
  transport-helper: clarify pushing without refspecs
  transport-helper: update refspec documentation
  transport-helper: clarify *:* refspec
  transport-helper: improve push messages
  transport-helper: mention helper name when it dies
  transport-helper: report errors properly

4 files changed, 118 insertions, 43 deletions

diff --git a/Documentation/gitremote-helpers.txt b/Documentation/gitremote-helpers.txt
index da746419b3..0827f69139 100644
--- a/Documentation/gitremote-helpers.txt
+++ b/Documentation/gitremote-helpers.txt
@@ -159,11 +159,11 @@ Miscellaneous capabilities
 	carried out.
 
 'refspec' <refspec>::
-	This modifies the 'import' capability, allowing the produced
-	fast-import stream to modify refs in a private namespace
-	instead of writing to refs/heads or refs/remotes directly.
+	For remote helpers that implement 'import' or 'export', this capability
+	allows the refs to be constrained to a private namespace, instead of
+	writing to refs/heads or refs/remotes directly.
 	It is recommended that all importers providing the 'import'
-	capability use this.
+	capability use this. It's mandatory for 'export'.
 +
 A helper advertising the capability
 `refspec refs/heads/*:refs/svn/origin/branches/*`
@@ -174,8 +174,8 @@ ref.
 This capability can be advertised multiple times.  The first
 applicable refspec takes precedence.  The left-hand of refspecs
 advertised with this capability must cover all refs reported by
-the list command.  If a helper does not need a specific 'refspec'
-capability then it should advertise `refspec *:*`.
+the list command.  If no 'refspec' capability is advertised,
+there is an implied `refspec *:*`.
 
 'bidi-import'::
 	This modifies the 'import' capability.
diff --git a/git-remote-testgit b/git-remote-testgit
index e7ed3a33e6..2b865deeb1 100755
--- a/git-remote-testgit
+++ b/git-remote-testgit
@@ -62,12 +62,31 @@ 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 "$GIT_REMOTE_TESTGIT_FAILURE"
+		then
+			# consume input so fast-export doesn't get SIGPIPE;
+			# git would also notice that case, but we want
+			# to make sure we are exercising the later
+			# error checks
+			while read line; do
+				test "done" = "$line" && break
+			done
+			exit 1
+		fi
+
 		before=$(git for-each-ref --format='%(refname) %(objectname)')
 
 		git fast-import "${testgitmarks_args[@]}" --quiet
@@ -79,7 +98,12 @@ do
 		while read ref a b
 		do
 			test $a == $b && continue
-			echo "ok $ref"
+			if test -z "$GIT_REMOTE_TESTGIT_PUSH_ERROR"
+			then
+				echo "ok $ref"
+			else
+				echo "error $ref $GIT_REMOTE_TESTGIT_PUSH_ERROR"
+			fi
 		done
 
 		echo
diff --git a/t/t5801-remote-helpers.sh b/t/t5801-remote-helpers.sh
index dbb02e2afd..16faa23154 100755
--- a/t/t5801-remote-helpers.sh
+++ b/t/t5801-remote-helpers.sh
@@ -101,39 +101,28 @@ test_expect_failure 'push new branch with old:new refspec' '
 
 test_expect_success 'cloning without refspec' '
 	GIT_REMOTE_TESTGIT_REFSPEC="" \
-	git clone "testgit::${PWD}/server" local2 &&
+	git clone "testgit::${PWD}/server" local2 2>error &&
+	grep "This remote helper should implement refspec capability" error &&
 	compare_refs local2 HEAD server HEAD
 '
 
 test_expect_success 'pulling without refspecs' '
 	(cd local2 &&
 	git reset --hard &&
-	GIT_REMOTE_TESTGIT_REFSPEC="" git pull) &&
+	GIT_REMOTE_TESTGIT_REFSPEC="" git pull 2>../error) &&
+	grep "This remote helper should implement refspec capability" error &&
 	compare_refs local2 HEAD server HEAD
 '
 
-test_expect_failure 'pushing without refspecs' '
+test_expect_success 'pushing without refspecs' '
 	test_when_finished "(cd local2 && git reset --hard origin)" &&
 	(cd local2 &&
 	echo content >>file &&
 	git commit -a -m ten &&
-	GIT_REMOTE_TESTGIT_REFSPEC="" git push) &&
-	compare_refs local2 HEAD server HEAD
-'
-
-test_expect_success 'pulling with straight refspec' '
-	(cd local2 &&
-	GIT_REMOTE_TESTGIT_REFSPEC="*:*" git pull) &&
-	compare_refs local2 HEAD server HEAD
-'
-
-test_expect_failure 'pushing with straight refspec' '
-	test_when_finished "(cd local2 && git reset --hard origin)" &&
-	(cd local2 &&
-	echo content >>file &&
-	git commit -a -m eleven &&
-	GIT_REMOTE_TESTGIT_REFSPEC="*:*" git push) &&
-	compare_refs local2 HEAD server HEAD
+	GIT_REMOTE_TESTGIT_REFSPEC="" &&
+	export GIT_REMOTE_TESTGIT_REFSPEC &&
+	test_must_fail git push 2>../error) &&
+	grep "remote-helper doesn.t support push; refspec needed" error
 '
 
 test_expect_success 'pulling without marks' '
@@ -186,6 +175,52 @@ test_expect_success GPG 'push signed tag with signed-tags capability' '
 	compare_refs local signed-tag-2 server signed-tag-2
 '
 
+test_expect_success 'push update refs' '
+	(cd local &&
+	git checkout -b update master &&
+	echo update >>file &&
+	git commit -a -m update &&
+	git push origin update &&
+	git rev-parse --verify remotes/origin/update >expect &&
+	git rev-parse --verify testgit/origin/heads/update >actual &&
+	test_cmp expect actual
+	)
+'
+
+test_expect_success 'push update refs failure' '
+	(cd local &&
+	git checkout update &&
+	echo "update fail" >>file &&
+	git commit -a -m "update fail" &&
+	git rev-parse --verify testgit/origin/heads/update >expect &&
+	GIT_REMOTE_TESTGIT_PUSH_ERROR="non-fast forward" &&
+	export GIT_REMOTE_TESTGIT_PUSH_ERROR &&
+	test_expect_code 1 git push origin update &&
+	git rev-parse --verify testgit/origin/heads/update >actual &&
+	test_cmp expect actual
+	)
+'
+
+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
+	)
+'
+
+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 helper .git-remote-testgit. failed" error
+	)
+'
+
 test_expect_success 'push messages' '
 	(cd local &&
 	git checkout -b new_branch master &&
diff --git a/transport-helper.c b/transport-helper.c
index 522d79178e..2f5ac3fbee 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -11,6 +11,7 @@
 #include "thread-utils.h"
 #include "sigchain.h"
 #include "argv-array.h"
+#include "refs.h"
 
 static int debug;
 
@@ -47,7 +48,7 @@ static void sendline(struct helper_data *helper, struct strbuf *buffer)
 		die_errno("Full write to remote helper failed");
 }
 
-static int recvline_fh(FILE *helper, struct strbuf *buffer)
+static int recvline_fh(FILE *helper, struct strbuf *buffer, const char *name)
 {
 	strbuf_reset(buffer);
 	if (debug)
@@ -55,7 +56,7 @@ 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 helper 'git-remote-%s' failed", name);
 	}
 
 	if (debug)
@@ -65,7 +66,7 @@ static int recvline_fh(FILE *helper, struct strbuf *buffer)
 
 static int recvline(struct helper_data *helper, struct strbuf *buffer)
 {
-	return recvline_fh(helper->out, buffer);
+	return recvline_fh(helper->out, buffer, helper->name);
 }
 
 static void xchgline(struct helper_data *helper, struct strbuf *buffer)
@@ -217,6 +218,8 @@ static struct child_process *get_helper(struct transport *transport)
 		for (i = 0; i < refspec_nr; i++)
 			free((char *)refspecs[i]);
 		free(refspecs);
+	} else if (data->import || data->bidi_import || data->export) {
+		warning("This remote helper should implement refspec capability.");
 	}
 	strbuf_release(&buf);
 	if (debug)
@@ -473,7 +476,7 @@ static int fetch_with_import(struct transport *transport,
 	 * were fetching.
 	 *
 	 * (If no "refspec" capability was specified, for historical
-	 * reasons we default to *:*.)
+	 * reasons we default to the equivalent of *:*.)
 	 *
 	 * Store the result in to_fetch[i].old_sha1.  Callers such
 	 * as "git fetch" can use the value to write feedback to the
@@ -540,7 +543,7 @@ static int process_connect_service(struct transport *transport,
 		goto exit;
 
 	sendline(data, &cmdbuf);
-	recvline_fh(input, &cmdbuf);
+	recvline_fh(input, &cmdbuf, name);
 	if (!strcmp(cmdbuf.buf, "")) {
 		data->no_disconnect_req = 1;
 		if (debug)
@@ -622,7 +625,7 @@ static int fetch(struct transport *transport,
 	return -1;
 }
 
-static void push_update_ref_status(struct strbuf *buf,
+static int push_update_ref_status(struct strbuf *buf,
 				   struct ref **ref,
 				   struct ref *remote_refs)
 {
@@ -688,7 +691,7 @@ static void push_update_ref_status(struct strbuf *buf,
 		*ref = find_ref_by_name(remote_refs, refname);
 	if (!*ref) {
 		warning("helper reported unexpected status of %s", refname);
-		return;
+		return 1;
 	}
 
 	if ((*ref)->status != REF_STATUS_NONE) {
@@ -697,11 +700,12 @@ static void push_update_ref_status(struct strbuf *buf,
 		 * status reported by the remote helper if the latter is 'no match'.
 		 */
 		if (status == REF_STATUS_NONE)
-			return;
+			return 1;
 	}
 
 	(*ref)->status = status;
 	(*ref)->remote_status = msg;
+	return !(status == REF_STATUS_OK);
 }
 
 static void push_update_refs_status(struct helper_data *data,
@@ -710,11 +714,24 @@ static void push_update_refs_status(struct helper_data *data,
 	struct strbuf buf = STRBUF_INIT;
 	struct ref *ref = remote_refs;
 	for (;;) {
+		char *private;
+
 		recvline(data, &buf);
 		if (!buf.len)
 			break;
 
-		push_update_ref_status(&buf, &ref, remote_refs);
+		if (push_update_ref_status(&buf, &ref, remote_refs))
+			continue;
+
+		if (!data->refspecs)
+			continue;
+
+		/* propagate back the update to the remote namespace */
+		private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
+		if (!private)
+			continue;
+		update_ref("update by helper", private, ref->new_sha1, NULL, 0, 0);
+		free(private);
 	}
 	strbuf_release(&buf);
 }
@@ -789,6 +806,9 @@ static int push_refs_with_export(struct transport *transport,
 	struct string_list revlist_args = STRING_LIST_INIT_NODUP;
 	struct strbuf buf = STRBUF_INIT;
 
+	if (!data->refspecs)
+		die("remote-helper doesn't support push; refspec needed");
+
 	helper = get_helper(transport);
 
 	write_constant(helper->in, "export\n");
@@ -799,8 +819,9 @@ static int push_refs_with_export(struct transport *transport,
 		char *private;
 		unsigned char sha1[20];
 
-		if (!data->refspecs)
-			continue;
+		if (ref->deletion)
+			die("remote-helpers do not support ref deletion");
+
 		private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
 		if (private && !get_sha1(private, sha1)) {
 			strbuf_addf(&buf, "^%s", private);
@@ -809,13 +830,8 @@ static int push_refs_with_export(struct transport *transport,
 		}
 		free(private);
 
-		if (ref->deletion) {
-			die("remote-helpers do not support ref deletion");
-		}
-
 		if (ref->peer_ref)
 			string_list_append(&revlist_args, ref->peer_ref->name);
-
 	}
 
 	if (get_exporter(transport, &exporter, &revlist_args))