"git cat-file: could not get object info" in webui

[fphammerle]

Describe the bug

Gogs responds to requests to https://git.hammerle.me/kjhammerle/cube-game-plus-plus/commit/914108b98f3ce4417f2af5b8b55a09fd68e8ed3f
with HTTP 500 and the following response body:

template: repo/diff/box:81:20: executing "repo/diff/box" at <call $.IsImageFileByIndex $file.Index>: error calling call: exit status 128 - fatal: git cat-file: could not get object info

I see no apparent reason why that particular commit would be invalid.

The tree view for the same commit works as expected: https://git.hammerle.me/kjhammerle/cube-game-plus-plus/src/914108b98f3ce4417f2af5b8b55a09fd68e8ed3f

Gogs version and commit

Application version: 0.12.3
Build commit: f0e3cd90f8d7695960eeef2e4e54b2e717302f6c 

Git version

$ git version
git version 2.30.2

Operating system

running docker.io/gogs/gogs@sha256:0195b095d0b29e5fd9fd44c0e4a544c981f8c8b2b7fb18ca61824694e31d279e via docker

Database
sqlite3

To Reproduce

1. Open https://git.hammerle.me/kjhammerle/cube-game-plus-plus/commit/914108b98f3ce4417f2af5b8b55a09fd68e8ed3f
2. Browser will show the error mentioned above

Can you reproduce the bug at https://try.gogs.io?
Different error on try.gogs.io, see https://try.gogs.io/fphammerle/cube-game-plus-plus/commit/914108b98f3ce4417f2af5b8b55a09fd68e8ed3f

template: repo/diff/box:81:20: executing "repo/diff/box" at <call $.IsImageFileByIndex $file.Index>: error calling call: exit status 128 - error: unable to find c187e25ecdba5875f5765acc967e35017985629e
fatal: git cat-file c187e25ecdba5875f5765acc967e35017985629e: bad file

Expected behavior
Webpage showing diff of commit, like https://git.hammerle.me/kjhammerle/cube-game-plus-plus/commit/5b06c611e21f994d38bb34ff1488f5ee0227d45d

Actual behavior
HTTP500 response with

template: repo/diff/box:81:20: executing "repo/diff/box" at <call $.IsImageFileByIndex $file.Index>: error calling call: exit status 128 - fatal: git cat-file: could not get object info

(no gogs UI)

Additional context
No new entry in log/gogs.log when accessing mentioned url.

[fphammerle]

I just tracked the git commands executed by gogs with

$ sudo strace -v -s64 -f -e execve -p $(pgrep gogs) 2>&1  | grep -oP 'cat-file.*?\]'

The responsible git command seems to be:

$ sudo docker exec -it -u git gogs bash
bash-5.0$ cd /data/git/gogs-repositories/kjhammerle/cube-game-plus-plus.git
bash-5.0$ git cat-file -t c187e25ecdba5875f5765acc967e35017985629e
fatal: git cat-file: could not get object info
bash-5.0$ 

[fphammerle]

c187e25ecdba5875f5765acc967e35017985629e is the commit hash of a just deleted submodule:

$ sudo docker exec -it -u git gogs bash
bash-5.0$ cd /data/git/gogs-repositories/kjhammerle/cube-game-plus-plus.gitbash-5.0$ git diff --full-index -M 5b06c611e21f994d38bb34ff1488f5ee0227d45d 914108b98f3ce4417f2af5b8b55a09fd68e8ed3f | grep -B 2 c187e25ecdba5875f5765acc967e35017985629e
diff --git a/enet b/enet
deleted file mode 160000
index c187e25ecdba5875f5765acc967e35017985629e..0000000000000000000000000000000000000000
--
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit c187e25ecdba5875f5765acc967e35017985629e
bash-5.0$ 

[fphammerle]

so in summary:

the issue is caused by gogs executing git cat-file -t c187e25ecdba5875f5765acc967e35017985629e

the git cat-file commands fails because c187e25ecdba5875f5765acc967e35017985629e is actually a commit in different repository ( zpl-c/enet@c187e25 ) that we previously included as a git submodule

[fphammerle]

associated source code:

{{if $file.IsDeleted}}
	{{$isImage = (call $.IsImageFileByIndex $file.Index)}}
{{else}}

in https://github.com/gogs/gogs/blob/v0.12.3/templates/repo/diff/box.tmpl#L81

[fphammerle]

associated:

// IsImageFileByIndex returns true if the blob of the commit is an image by index.
func (c *Commit) IsImageFileByIndex(index string) (bool, error) {
	return c.isImageFile(c.BlobByIndex(index))
}

https://github.com/gogs/git-module/blob/v1.1.4/commit.go#L170