[PATCH v2 1/2] for-each-repo: optionally keep going on an error

["Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com>]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

In https://github.com/microsoft/git/issues/623, it was reported that
the regularly scheduled maintenance stops if one repo in the middle of
the list was found to be missing.

This is undesirable, and points out a gap in the design of `git
for-each-repo`: We need a mode where that command does not stop on an
error, but continues to try running the specified command with the other
repositories.

Imitating the `--keep-going` option of GNU make, this commit teaches
`for-each-repo` the same trick: to continue with the operation on all
the remaining repositories in case there was a problem with one
repository, still setting the exit code to indicate an error occurred.

Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 Documentation/git-for-each-repo.txt |  4 ++++
 builtin/for-each-repo.c             |  8 ++++++--
 t/t0068-for-each-repo.sh            | 16 ++++++++++++++++
 3 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/Documentation/git-for-each-repo.txt b/Documentation/git-for-each-repo.txt
index 94bd19da263..8c18001d825 100644
--- a/Documentation/git-for-each-repo.txt
+++ b/Documentation/git-for-each-repo.txt
@@ -42,6 +42,10 @@ These config values are loaded from system, global, and local Git config,
 as available. If `git for-each-repo` is run in a directory that is not a
 Git repository, then only the system and global config is used.
 
+--keep-going::
+	Continue with the remaining repositories if the command failed
+	on a repository. The exit code will still indicate that the
+	overall operation was not successful.
 
 SUBPROCESS BEHAVIOR
 -------------------
diff --git a/builtin/for-each-repo.c b/builtin/for-each-repo.c
index 28186b30f54..9bdf2b34f89 100644
--- a/builtin/for-each-repo.c
+++ b/builtin/for-each-repo.c
@@ -32,6 +32,7 @@ static int run_command_on_repo(const char *path, int argc, const char ** argv)
 int cmd_for_each_repo(int argc, const char **argv, const char *prefix)
 {
 	static const char *config_key = NULL;
+	int keep_going = 0;
 	int i, result = 0;
 	const struct string_list *values;
 	int err;
@@ -39,6 +40,8 @@ int cmd_for_each_repo(int argc, const char **argv, const char *prefix)
 	const struct option options[] = {
 		OPT_STRING(0, "config", &config_key, N_("config"),
 			   N_("config key storing a list of repository paths")),
+		OPT_BOOL(0, "keep-going", &keep_going,
+			 N_("keep going even if command fails in a repository")),
 		OPT_END()
 	};
 
@@ -55,8 +58,9 @@ int cmd_for_each_repo(int argc, const char **argv, const char *prefix)
 	else if (err)
 		return 0;
 
-	for (i = 0; !result && i < values->nr; i++)
-		result = run_command_on_repo(values->items[i].string, argc, argv);
+	for (i = 0; (keep_going || !result) && i < values->nr; i++)
+		if (run_command_on_repo(values->items[i].string, argc, argv))
+			result = 1;
 
 	return result;
 }
diff --git a/t/t0068-for-each-repo.sh b/t/t0068-for-each-repo.sh
index 4b90b74d5d5..95019e01ed3 100755
--- a/t/t0068-for-each-repo.sh
+++ b/t/t0068-for-each-repo.sh
@@ -59,4 +59,20 @@ test_expect_success 'error on NULL value for config keys' '
 	test_cmp expect actual
 '
 
+test_expect_success '--keep-going' '
+	git config keep.going non-existing &&
+	git config --add keep.going . &&
+
+	test_must_fail git for-each-repo --config=keep.going \
+		-- branch >out 2>err &&
+	test_grep "cannot change to .*non-existing" err &&
+	test_must_be_empty out &&
+
+	test_must_fail git for-each-repo --config=keep.going --keep-going \
+		-- branch >out 2>err &&
+	test_grep "cannot change to .*non-existing" err &&
+	git branch >expect &&
+	test_cmp expect out
+'
+
 test_done
-- 
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