Bug unityYAMLMerge messing up merged code by adding line breaks

For some reason, unityYAMLmerge in PlasticSCM when used with prefabs adds line breaks to pretty much all existing lines (even lines that needn't be merged)

This can't be by design can it?, as this makes double checking merges completely impossible.

Am I doing something wrong? Is this a bug?

See attached screenshot.

Unity 2021.3.20f with PlasticSCM (or whatever the f it's now called) 11.0.16.8060

 

Yeah, it's an old bug of UnityYAMLMerge.exe, and so far they haven't bothered to fix that :-/
See footnote here: https://uninomicon.com/yamlmerge
So PlasticSCM is not at fault, but since it internally calls UnityYAMLMerge, this problem becomes visible.

There is a relatively new (>=2020.x?) Editor setting SerializeInlineMappingsOnOneLine, which appears to be ON by default - but UnityYAMLMerge completely ignores this, and always creates output emulated with this setting OFF.



https://docs.unity3d.com/2020.1/Doc...ettings-serializeInlineMappingsOnOneLine.html

Until Unity fixes this, your best bet will probably be to DISABLE this flag, and force-reimport all scenes+prefabs once (untested - will probably not help directly, as a re-import generally doesn't modify the Assets, only the metadada).
Another method would be to disallow PlasticSCM from calling UnityYAMLMerge, by configuring its MergeTools for the entry ".prefab;.unity", so it uses the regular diff tool instead - at the cost of possibly slightly less intelligent diffs.