Improve listing performance by using go-git (#6478)

* Use go-git for tree reading and commit info lookup.

Signed-off-by: Filip Navara <navara@emclient.com>

* Use TreeEntry.IsRegular() instead of ObjectType that was removed.

Signed-off-by: Filip Navara <navara@emclient.com>

* Use the treePath to optimize commit info search.

Signed-off-by: Filip Navara <navara@emclient.com>

* Extract the latest commit at treePath along with the other commits.

Signed-off-by: Filip Navara <navara@emclient.com>

* Fix listing commit info for a directory that was created in one commit and never modified after.

Signed-off-by: Filip Navara <navara@emclient.com>

* Avoid nearly all external 'git' invocations when doing directory listing (.editorconfig code path is still hit).

Signed-off-by: Filip Navara <navara@emclient.com>

* Use go-git for reading blobs.

Signed-off-by: Filip Navara <navara@emclient.com>

* Make SHA1 type alias for plumbing.Hash in go-git.

Signed-off-by: Filip Navara <navara@emclient.com>

* Make Signature type alias for object.Signature in go-git.

Signed-off-by: Filip Navara <navara@emclient.com>

* Fix GetCommitsInfo for repository with only one commit.

Signed-off-by: Filip Navara <navara@emclient.com>

* Fix PGP signature verification.

Signed-off-by: Filip Navara <navara@emclient.com>

* Fix issues with walking commit graph across merges.

Signed-off-by: Filip Navara <navara@emclient.com>

* Fix typo in condition.

Signed-off-by: Filip Navara <navara@emclient.com>

* Speed up loading branch list by keeping the repository reference (and thus all the loaded packfile indexes).

Signed-off-by: Filip Navara <navara@emclient.com>

* Fix lising submodules.

Signed-off-by: Filip Navara <navara@emclient.com>

* Fix build

Signed-off-by: Filip Navara <navara@emclient.com>

* Add back commit cache because of name-rev

Signed-off-by: Filip Navara <navara@emclient.com>

* Fix tests

Signed-off-by: Filip Navara <navara@emclient.com>

* Fix code style

* Fix spelling

* Address PR feedback

Signed-off-by: Filip Navara <navara@emclient.com>

* Update vendor module list

Signed-off-by: Filip Navara <navara@emclient.com>

* Fix getting trees by commit id

Signed-off-by: Filip Navara <navara@emclient.com>

* Fix remaining unit test failures

* Fix GetTreeBySHA

* Avoid running `git name-rev` if not necessary

Signed-off-by: Filip Navara <navara@emclient.com>

* Move Branch code to git module

* Clean up GPG signature verification and fix it for tagged commits

* Address PR feedback (import formatting, copyright headers)

* Make blob lookup by SHA working

* Update tests to use public API

* Allow getting content from any type of object through the blob interface

* Change test to actually expect the object content that is in the GIT repository

* Change one more test to actually expect the object content that is in the GIT repository

* Add comments

modules/git/parse_test.go

@@ -8,6 +8,8 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"gopkg.in/src-d/go-git.v4/plumbing/filemode"
+	"gopkg.in/src-d/go-git.v4/plumbing/object"
 )
 
 func TestParseTreeEntries(t *testing.T) {
@@ -23,10 +25,12 @@ func TestParseTreeEntries(t *testing.T) {
 			Input: "100644 blob 61ab7345a1a3bbc590068ccae37b8515cfc5843c\texample/file2.txt\n",
 			Expected: []*TreeEntry{
 				{
-					mode: EntryModeBlob,
-					Type: ObjectBlob,
-					ID:   MustIDFromString("61ab7345a1a3bbc590068ccae37b8515cfc5843c"),
-					name: "example/file2.txt",
+					ID: MustIDFromString("61ab7345a1a3bbc590068ccae37b8515cfc5843c"),
+					gogitTreeEntry: &object.TreeEntry{
+						Hash: MustIDFromString("61ab7345a1a3bbc590068ccae37b8515cfc5843c"),
+						Name: "example/file2.txt",
+						Mode: filemode.Regular,
+					},
 				},
 			},
 		},
@@ -35,16 +39,20 @@ func TestParseTreeEntries(t *testing.T) {
 				"040000 tree 1d01fb729fb0db5881daaa6030f9f2d3cd3d5ae8\texample\n",
 			Expected: []*TreeEntry{
 				{
-					ID:   MustIDFromString("61ab7345a1a3bbc590068ccae37b8515cfc5843c"),
-					Type: ObjectBlob,
-					mode: EntryModeSymlink,
-					name: "example/\n.txt",
+					ID: MustIDFromString("61ab7345a1a3bbc590068ccae37b8515cfc5843c"),
+					gogitTreeEntry: &object.TreeEntry{
+						Hash: MustIDFromString("61ab7345a1a3bbc590068ccae37b8515cfc5843c"),
+						Name: "example/\n.txt",
+						Mode: filemode.Symlink,
+					},
 				},
 				{
-					ID:   MustIDFromString("1d01fb729fb0db5881daaa6030f9f2d3cd3d5ae8"),
-					Type: ObjectTree,
-					mode: EntryModeTree,
-					name: "example",
+					ID: MustIDFromString("1d01fb729fb0db5881daaa6030f9f2d3cd3d5ae8"),
+					gogitTreeEntry: &object.TreeEntry{
+						Hash: MustIDFromString("1d01fb729fb0db5881daaa6030f9f2d3cd3d5ae8"),
+						Name: "example",
+						Mode: filemode.Dir,
+					},
 				},
 			},
 		},