Showing a diff sometimes crashes vim on windows

[TimUntersberger]

This is probably an upstream bug. Sometimes toggling a diff for the first time can crash neovim when creating the fold

[TimUntersberger]

@bfredl do you know what could cause this? I can sometimes reproduce this 100% (when certain conditions are met, which I don't know yet) on windows, but never on linux.

Doing <from>,<to>fold is the source of the problem.

I can record a video for you if this could help you.

[hkupty]

To me, on linux, it gives me a segfault if I enable diff 3/4 when I have something staged. I'm not sure it's the same issue, but definitely it looks like so.

[TimUntersberger]

To me, on linux, it gives me a segfault if I enable diff 3/4 when I have something staged. I'm not sure it's the same issue, but definitely it looks like so.

Can you reproduce this with a different repo? For me this is happening completely random and I don't know what the problem is.

[hkupty]

It happened to me on three different repos, one being this, one being my dotfiles and another is a java codebase. Completely different repos.

[TimUntersberger]

Is it always the same position (like 4th staged change or something like that)?

For me it has happend when only 1 file was unstaged or when I had a lot of files open.

[hkupty]

1 or more staged, sometimes not even staged, but I guess it's probably something else. Im assuming it's on gits side, when getting the patches, rather than on displaying...

[TimUntersberger]

It has to do something with fold though. When I remove the folds it doesn't crash anymore. This is overall very weird.

[hkupty]

Modified lua/neogit/status.lua
@@ -59,7 +59,7 @@ local function insert_diff(section, change)
     return
   end
 
-  vim.cmd("normal zd")
+  --vim.cmd("normal zd")
 
   if not change.diff_content then
     if section.name == "staged_changes" then

Ok, I've isolated it to this line. When I comment this command, it never breaks for me.

[hkupty]

I don't know the intent of this zd command, but it seems from my manual testing that neogit works well without it.

[TimUntersberger]

zd deletes the fold under the current line. I honestly don't remember why I delete the fold under the current line. Do you know of any way to get a backtrace for the vim crash? The debug and log features don't really return anything useful for me.

Edit: I think we need zd, because each change has an empty fold in the beginning, which has to be deleted (I think).

[hkupty]

I found that by accident by manually running zd and getting an error message (something like no fold to be deleted). Is there a way to check if there's actually a fold there before you run zd?

Do you know of any way to get a backtrace for the vim crash?

Unfortunately no.

Another alternative would be to test without the shorthand version vim.cmd, using vim.api.nvim_command. this can be helpful to isolate where is the issue.

[TimUntersberger]

I just tested without the zd and it still crashes for me. I only don't crash when i remove the create_fold calls.

[TimUntersberger]

Manually doing the <start>,<end>fold excommand with the same arguments also crashes neovim for me, so this has to do something with neovim.

[hkupty]

Ok, so maybe we're having different issues on Windows and Linux :/