grep: optionally recurse into submodules

Allow grep to recognize submodules and recursively search for patterns in
each submodule.  This is done by forking off a process to recursively
call grep on each submodule.  The top level --super-prefix option is
used to pass a path to the submodule which can in turn be used to
prepend to output or in pathspec matching logic.

Recursion only occurs for submodules which have been initialized and
checked out by the parent project.  If a submodule hasn't been
initialized and checked out it is simply skipped.

In order to support the existing multi-threading infrastructure in grep,
output from each child process is captured in a strbuf so that it can be
later printed to the console in an ordered fashion.

To limit the number of theads that are created, each child process has
half the number of threads as its parents (minimum of 1), otherwise we
potentailly have a fork-bomb.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 99 insertions, 0 deletions

diff --git a/t/t7814-grep-recurse-submodules.sh b/t/t7814-grep-recurse-submodules.sh
new file mode 100755
index 0000000..1019125
--- /dev/null
+++ b/t/t7814-grep-recurse-submodules.sh
@@ -0,0 +1,99 @@
+#!/bin/sh
+
+test_description='Test grep recurse-submodules feature
+
+This test verifies the recurse-submodules feature correctly greps across
+submodules.
+'
+
+. ./test-lib.sh
+
+test_expect_success 'setup directory structure and submodule' '
+	echo "foobar" >a &&
+	mkdir b &&
+	echo "bar" >b/b &&
+	git add a b &&
+	git commit -m "add a and b" &&
+	git init submodule &&
+	echo "foobar" >submodule/a &&
+	git -C submodule add a &&
+	git -C submodule commit -m "add a" &&
+	git submodule add ./submodule &&
+	git commit -m "added submodule"
+'
+
+test_expect_success 'grep correctly finds patterns in a submodule' '
+	cat >expect <<-\EOF &&
+	a:foobar
+	b/b:bar
+	submodule/a:foobar
+	EOF
+
+	git grep -e "bar" --recurse-submodules >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'grep and basic pathspecs' '
+	cat >expect <<-\EOF &&
+	submodule/a:foobar
+	EOF
+
+	git grep -e. --recurse-submodules -- submodule >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'grep and nested submodules' '
+	git init submodule/sub &&
+	echo "foobar" >submodule/sub/a &&
+	git -C submodule/sub add a &&
+	git -C submodule/sub commit -m "add a" &&
+	git -C submodule submodule add ./sub &&
+	git -C submodule add sub &&
+	git -C submodule commit -m "added sub" &&
+	git add submodule &&
+	git commit -m "updated submodule" &&
+
+	cat >expect <<-\EOF &&
+	a:foobar
+	b/b:bar
+	submodule/a:foobar
+	submodule/sub/a:foobar
+	EOF
+
+	git grep -e "bar" --recurse-submodules >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'grep and multiple patterns' '
+	cat >expect <<-\EOF &&
+	a:foobar
+	submodule/a:foobar
+	submodule/sub/a:foobar
+	EOF
+
+	git grep -e "bar" --and -e "foo" --recurse-submodules >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'grep and multiple patterns' '
+	cat >expect <<-\EOF &&
+	b/b:bar
+	EOF
+
+	git grep -e "bar" --and --not -e "foo" --recurse-submodules >actual &&
+	test_cmp expect actual
+'
+
+test_incompatible_with_recurse_submodules ()
+{
+	test_expect_success "--recurse-submodules and $1 are incompatible" "
+		test_must_fail git grep -e. --recurse-submodules $1 2>actual &&
+		test_i18ngrep 'not supported with --recurse-submodules' actual
+	"
+}
+
+test_incompatible_with_recurse_submodules --untracked
+test_incompatible_with_recurse_submodules --no-index
+test_incompatible_with_recurse_submodules HEAD
+
+test_done