grep: enable recurse-submodules to work on <tree> objects

Teach grep to recursively search in submodules when provided with a
<tree> object. This allows grep to search a submodule based on the state
of the submodule that is present in a commit of the super project.

When grep is provided with a <tree> object, the name of the object is
prefixed to all output.  In order to provide uniformity of output
between the parent and child processes the option `--parent-basename`
has been added so that the child can preface all of it's output with the
name of the parent's object instead of the name of the commit SHA1 of
the submodule. This changes output from the command
`git grep -e. -l --recurse-submodules HEAD` from:

      HEAD:file
      <commit sha1 of submodule>:sub/file

to:

      HEAD:file
      HEAD:sub/file

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

1 files changed, 102 insertions, 1 deletions

diff --git a/t/t7814-grep-recurse-submodules.sh b/t/t7814-grep-recurse-submodules.sh
index 1019125..d5fc316 100755
--- a/t/t7814-grep-recurse-submodules.sh
+++ b/t/t7814-grep-recurse-submodules.sh
@@ -84,6 +84,108 @@ test_expect_success 'grep and multiple patterns' '
 	test_cmp expect actual
 '
 
+test_expect_success 'basic grep tree' '
+	cat >expect <<-\EOF &&
+	HEAD:a:foobar
+	HEAD:b/b:bar
+	HEAD:submodule/a:foobar
+	HEAD:submodule/sub/a:foobar
+	EOF
+
+	git grep -e "bar" --recurse-submodules HEAD >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'grep tree HEAD^' '
+	cat >expect <<-\EOF &&
+	HEAD^:a:foobar
+	HEAD^:b/b:bar
+	HEAD^:submodule/a:foobar
+	EOF
+
+	git grep -e "bar" --recurse-submodules HEAD^ >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'grep tree HEAD^^' '
+	cat >expect <<-\EOF &&
+	HEAD^^:a:foobar
+	HEAD^^:b/b:bar
+	EOF
+
+	git grep -e "bar" --recurse-submodules HEAD^^ >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'grep tree and pathspecs' '
+	cat >expect <<-\EOF &&
+	HEAD:submodule/a:foobar
+	HEAD:submodule/sub/a:foobar
+	EOF
+
+	git grep -e "bar" --recurse-submodules HEAD -- submodule >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'grep tree and pathspecs' '
+	cat >expect <<-\EOF &&
+	HEAD:submodule/a:foobar
+	HEAD:submodule/sub/a:foobar
+	EOF
+
+	git grep -e "bar" --recurse-submodules HEAD -- "submodule*a" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'grep tree and more pathspecs' '
+	cat >expect <<-\EOF &&
+	HEAD:submodule/a:foobar
+	EOF
+
+	git grep -e "bar" --recurse-submodules HEAD -- "submodul?/a" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'grep tree and more pathspecs' '
+	cat >expect <<-\EOF &&
+	HEAD:submodule/sub/a:foobar
+	EOF
+
+	git grep -e "bar" --recurse-submodules HEAD -- "submodul*/sub/a" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success !MINGW 'grep recurse submodule colon in name' '
+	git init parent &&
+	test_when_finished "rm -rf parent" &&
+	echo "foobar" >"parent/fi:le" &&
+	git -C parent add "fi:le" &&
+	git -C parent commit -m "add fi:le" &&
+
+	git init "su:b" &&
+	test_when_finished "rm -rf su:b" &&
+	echo "foobar" >"su:b/fi:le" &&
+	git -C "su:b" add "fi:le" &&
+	git -C "su:b" commit -m "add fi:le" &&
+
+	git -C parent submodule add "../su:b" "su:b" &&
+	git -C parent commit -m "add submodule" &&
+
+	cat >expect <<-\EOF &&
+	fi:le:foobar
+	su:b/fi:le:foobar
+	EOF
+	git -C parent grep -e "foobar" --recurse-submodules >actual &&
+	test_cmp expect actual &&
+
+	cat >expect <<-\EOF &&
+	HEAD:fi:le:foobar
+	HEAD:su:b/fi:le:foobar
+	EOF
+	git -C parent grep -e "foobar" --recurse-submodules HEAD >actual &&
+	test_cmp expect actual
+'
+
 test_incompatible_with_recurse_submodules ()
 {
 	test_expect_success "--recurse-submodules and $1 are incompatible" "
@@ -94,6 +196,5 @@ test_incompatible_with_recurse_submodules ()
 
 test_incompatible_with_recurse_submodules --untracked
 test_incompatible_with_recurse_submodules --no-index
-test_incompatible_with_recurse_submodules HEAD
 
 test_done