Improve determinism of UIDs by KoBeWi · Pull Request #111858 · godotengine/godot

KoBeWi · 2025-10-20T21:50:41Z

This makes path-based UID generation case-insensitive, which improves consistency on case-insensitive systems. For example if 2 people generate UID for a file, but the file has different casing on each side (just Windows things), the UID will be the same.

~~Also fixes UID not being deterministic when duplicating files (regression (?) from #106763).~~

AThousandShips · 2025-10-20T22:12:07Z

This feels unsafe, this will make res://foo/bar.gd and res://Foo/bar.gd have the same UID if the files are identical in content, that might make sense on case-insensitive filesystems but not in general

I'm not sure this "fixes" anything and just helps in cases where users violate best practices as documented etc.

KoBeWi · 2025-10-20T22:21:54Z

This feels unsafe, this will make res://foo/bar.gd and res://Foo/bar.gd have the same UID if the files are identical in content, that might make sense on case-insensitive filesystems but not in general

Do people keep multiple files where only casing is different? Yes, this can happen, it sounds unlikely, even if it's technically allowed in case-sensitive filesystems.

Either way, the UID system is able to deal with collisions, so no duplicate UID will be created.

AThousandShips · 2025-10-20T22:27:58Z

I'd say it's about as likely or as reasonable as mixing casing across platforms/users in a shared project

coppolaemilio · 2025-10-20T22:32:13Z

@AThousandShips this is addressing a report Godot users that are making games are having, the having two files: res://foo/bar.gd and res://Foo/bar.gd is a completely hypothetical you are creating, so I don't think it is a good argument against it

AThousandShips · 2025-10-20T22:33:44Z

I didn't refute it happening, but the fact remains that the error comes from breaking best practices, which I think should at least be considered hence bringing it up

coppolaemilio · 2025-10-20T22:35:47Z

unfortunately, windows will some times make it seem like you renamed the file but you actually didn't, so users think they are submitting files with the correct casing and it is not how they are stored internally. You can of course notice this in GitHub before pushing a change, but an artist working on a game might not :(

AThousandShips · 2025-10-20T22:39:28Z

That casing difference will cause other bugs though and issues with git, hence not best practices

But if the UID system handles conflicts then I guess it'd be safe to account for this incorrect usage, and hopefully things won't be more confusing for such users more if the UID system is more lenient

(Also, no need to tag when I'm right in the conversation, it just sounds like you're calling me out rather than just bringing to my attention)

coppolaemilio · 2025-10-20T22:42:41Z

sorry for the tag, rocketchat ptsd from people not getting notified 😅

AThousandShips · 2025-10-20T22:45:07Z

That is very relatable! The internet is a weird place with the extremes of Facebook with the worst tags, and RC of never getting the tags you're actually interested in

AThousandShips

I think we can safely go ahead with this, but I think it's only a band-aid for a more serious problem of the editor not helping users to follow proper best practices, I'd say a more proper solution to prevent these issues would involve:

Warning, or even throwing an error, when renaming a file just changing the casing on a case-insensitive OS, something like "cannot rename file on a case-insensitive system, file will not be moved", alternatively adding some system on these OSes to move a file properly by moving to a temporary and then moving back Realized this has actually been fixed already
Warning on case-sensitive systems when renaming in the same way, saying that "these changes will have no effect when running on a case-insensitive operating system" or similar to warn that renaming them and updating VCS won't work on those OSes and will be confusing
More proactive detection in the editor for case errors, like in load("res://foo/bar.gd) if there is a file res://Foo/bar.gd, not just when running but as a warning in the editor

Edit: Opened a proposal for usability improvements with respect to casing

godotengine/godot-proposals#13436

Retracting approval until this has been confirmed to fix existing bugs, as opposed to hypothetical issues

AThousandShips · 2025-10-22T09:22:45Z

Just to confirm: this does not cause any already assigned UIDs to be changed, i.e. for any files with .import or .uid files or for any .(t)res or .(t)scn files?

KoBeWi · 2025-10-22T09:58:53Z

No, it's only for new UIDs.

core/io/resource_uid.cpp

Calinou

Tested locally on Linux (case-sensitive btrfs filesystem), it doesn't seem to work on my end:

$ cat touch.gd.uid TOUCH.gd.uid 
uid://bxr365upoga6i
uid://b320arqlsxif0

Both files have the same content:

extends CanvasLayer


func _ready() -> void:
	hide()
	if DisplayServer.is_touchscreen_available():
		show()

I've removed both .uid files beforehand to force them to be regenerated.

coppolaemilio · 2025-10-28T14:56:04Z

Tested locally on Linux (case-sensitive btrfs filesystem), it doesn't seem to work on my end:

I believe that is intended? to test this you would have to generate one, and then remove it and try with the other one. Kobewi said that there is already a failsafe to generate a new code if the current one exists

KoBeWi · 2025-10-28T16:01:03Z

Yes, you can test it like this:

Create icon.svg
Delete it
Create ICON.svg (or any different casing variation)

The UID should be the same for both files.

Calinou · 2025-10-28T18:40:57Z

Yes, you can test it like this:
* Create icon.svg

* Delete it

* Create ICON.svg (or any different casing variation)
The UID should be the same for both files.

That makes sense. I've tested it again following these steps, and it works as expected.

bruvzg

Makes sense. Cases with two files that are only different in the name case are non-portable, and should be avoided regardless of this change.

akien-mga

I think this makes sense, this is a common source of issue for cross-platform teams that leads to UID regeneration churn and diff noise.

akien-mga · 2026-01-06T10:04:26Z

Thanks!

gnat · 2026-01-08T17:48:28Z

For the record, another scenario where this PR is good: Programs which switch the case of extensions between lower or upper case (ex: .png vs .PNG, .psd vs .PSD).

akien-mga · 2026-01-08T23:08:29Z

Cherry-picked for 4.5.2.

Improve determinism of UIDs

KoBeWi added this to the 4.6 milestone Oct 20, 2025

KoBeWi requested a review from a team October 20, 2025 21:50

KoBeWi requested a review from a team as a code owner October 20, 2025 21:50

KoBeWi added enhancement topic:core cherrypick:4.5 Considered for cherry-picking into a future 4.5.x release labels Oct 20, 2025

AThousandShips added the discussion label Oct 20, 2025

AThousandShips previously approved these changes Oct 21, 2025

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AThousandShips mentioned this pull request Oct 21, 2025

Improve platform interoperability for casing differences in the editor godotengine/godot-proposals#13436

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KoBeWi mentioned this pull request Oct 24, 2025

Fix file duplication making random UID #112015

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KoBeWi force-pushed the IcOn.SvG branch from 2ee4af8 to ff505d3 Compare October 24, 2025 21:05

Calinou reviewed Oct 28, 2025

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Improve determinism of UIDs

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KoBeWi force-pushed the IcOn.SvG branch from ff505d3 to 1af77aa Compare October 28, 2025 21:05

akien-mga requested a review from bruvzg December 19, 2025 09:54

bruvzg approved these changes Jan 6, 2026

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akien-mga approved these changes Jan 6, 2026

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akien-mga added the usability label Jan 6, 2026

akien-mga merged commit 5acd0c0 into godotengine:master Jan 6, 2026
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KoBeWi deleted the IcOn.SvG branch January 6, 2026 10:35

akien-mga removed the cherrypick:4.5 Considered for cherry-picking into a future 4.5.x release label Jan 8, 2026

rivie13 pushed a commit to rivie13/Phoenix-Agentic-Engine that referenced this pull request Feb 16, 2026

Merge pull request godotengine#111858 from KoBeWi/IcOn.SvG

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Improve determinism of UIDs

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