Error creating Mixin config fabric-block-view-api-v2.client.mixins.json for mod fabric-block-view-api-v2

[xc0ff33]

Description

I loaded up my mod for the first time using this...

...then this error occurs. I don't think I'm behind it. It seems to be caused by parts of the Fabric API. The problematic API branch changes every time I run it, which is very weird.
Two examples of such errors:

Uncaught exception in thread "main"
java.lang.RuntimeException: Error creating Mixin config fabric-block-view-api-v2.client.mixins.json for mod fabric-block-view-api-v2
	at net.fabricmc.loader.impl.launch.FabricMixinBootstrap.init(FabricMixinBootstrap.java:96)
	at net.fabricmc.loader.impl.launch.knot.Knot.init(Knot.java:151)
	at net.fabricmc.loader.impl.launch.knot.Knot.launch(Knot.java:68)
	at net.fabricmc.loader.impl.launch.knot.KnotClient.main(KnotClient.java:23)
	at net.fabricmc.devlaunchinjector.Main.main(Main.java:86)
Caused by: org.spongepowered.asm.launch.MixinInitialisationError: Error initialising mixin config fabric-block-view-api-v2.client.mixins.json
	at org.spongepowered.asm.mixin.transformer.Config.create(Config.java:153)
	at org.spongepowered.asm.mixin.Mixins.createConfiguration(Mixins.java:100)
	at org.spongepowered.asm.mixin.Mixins.addConfiguration(Mixins.java:87)
	at net.fabricmc.loader.impl.launch.FabricMixinBootstrap.init(FabricMixinBootstrap.java:94)
	... 4 more
Caused by: java.lang.IllegalArgumentException: The specified resource 'fabric-block-view-api-v2.client.mixins.json' was invalid or could not be read
	at org.spongepowered.asm.mixin.transformer.MixinConfig.create(MixinConfig.java:1290)
	at org.spongepowered.asm.mixin.transformer.Config.create(Config.java:148)
	... 7 more

Uncaught exception in thread "main"
java.lang.RuntimeException: Error creating Mixin config fabric-object-builder-v1.client.mixins.json for mod fabric-object-builder-api-v1
	at net.fabricmc.loader.impl.launch.FabricMixinBootstrap.init(FabricMixinBootstrap.java:96)
	at net.fabricmc.loader.impl.launch.knot.Knot.init(Knot.java:151)
	at net.fabricmc.loader.impl.launch.knot.Knot.launch(Knot.java:68)
	at net.fabricmc.loader.impl.launch.knot.KnotClient.main(KnotClient.java:23)
	at net.fabricmc.devlaunchinjector.Main.main(Main.java:86)
Caused by: org.spongepowered.asm.launch.MixinInitialisationError: Error initialising mixin config fabric-object-builder-v1.client.mixins.json
	at org.spongepowered.asm.mixin.transformer.Config.create(Config.java:153)
	at org.spongepowered.asm.mixin.Mixins.createConfiguration(Mixins.java:100)
	at org.spongepowered.asm.mixin.Mixins.addConfiguration(Mixins.java:87)
	at net.fabricmc.loader.impl.launch.FabricMixinBootstrap.init(FabricMixinBootstrap.java:94)
	... 4 more
Caused by: java.lang.IllegalArgumentException: The specified resource 'fabric-object-builder-v1.client.mixins.json' was invalid or could not be read
	at org.spongepowered.asm.mixin.transformer.MixinConfig.create(MixinConfig.java:1290)
	at org.spongepowered.asm.mixin.transformer.Config.create(Config.java:148)
	... 7 more

Here is my fabric.mod.json:

{
	"schemaVersion": 1,
	"id": "gainhearts",
	"version": "${1.0.0}",
	"name": "GainHearts",
	"description": "GainHearts is a small Minecraft mod I built for my cousin. You get hearts when doing things.",
	"authors": [
		"xc0ff33"
	],
	"contact": {
		"homepage": "// there is a link to a private repo",
		"sources": "// there is a link to a private repo"
	},
	"license": "CC0-1.0",
	"icon": "assets/gainhearts/icon.png",
	"environment": "*",
	"entrypoints": {
		"main": [
			"com.gainhearts.GainHearts"
		]
	},
	"mixins": [
		"gainhearts.mixins.json"
	],
	"depends": {
		"fabricloader": ">=0.15.0",
		"minecraft": "~1.20.4",
		"java": ">=17",
		"fabric-api": "*"
	},
	"suggests": {
		"another-mod": "*"
	}
}

Here is my gainhearts.mixins.json:

{
  "required": true,
  "package": "com.gainhearts.mixin",
  "compatibilityLevel": "JAVA_17",
  "mixins": [
    "BlockBreakMixin",
    "EntityKillMixin"
  ],
  "injectors": {
    "defaultRequire": 1
	}
}

[Xiang990293]

same issue after update to 1.20.6, but every time I restart the client, different api ent wrong, kinda weird...

[Pyrix25633]

I have the exact same error, It's annoying and doesn't make sense.

[RudideC]

Is there any current fix for this issue?

[iamcal]

I'm experiencing the same thing with a completely fresh mod from the template generator. This happens when launching via the IDEA client build target, but ./gradlew runClient works successfully.

[RudideC]

Thanks

[iamcal]

When I started over with a new project from the template creator and did not check "Data Generation", the newly created project worked fine. The issue appears to be related to data generation.

[BrandonLegault]

Same problem here. Data Generation (as mentioned above) has no effect on the issue.

Maybe relevent:

It only happens when spongepowered is trying to resolve client mixins (x.client.mixins.json). This call: InputStream resource = service.getResourceAsStream(configFile); fails in spongepowered even though the .jar file exists in the same location as the regular, non-client mixins, which succeed no problem.

[DJR-dev]

base game issue emphasized by fabric(MC-273135)