Add support for Minecraft 26.1

[PaintNinja]

Attempting to use FG7 for a cleandev 26.1 environment fails with an exception stating that it doesn't have "a MCPConfig ror official mappings":

> Configure project :minecraft
Minecraft Mavenizer 0.4.25 by Forge Development LLC
  Output:             C:\Users\oscar\Documents\Projects\ModuleLoader\.gradle\mavenizer\repo
  Output JSON:        C:\Users\oscar\Documents\Projects\ModuleLoader\.gradle\mavenizer\dependencies\default.json
  Dependencies Only:  false
  Cache:              C:\Users\oscar\.gradle\caches\minecraftforge\forgegradle\mavenizer\caches
  JDK Cache:          C:\Users\oscar\.gradle\caches\minecraftforge\forgegradle\mavenizer\caches
  Offline:            false
  Cache Only:         false
  Mappings:           official
  Foreign Repos:      [https://repo.maven.apache.org/maven2/, https://maven.minecraftforge.net/, file:/C:/Users/oscar/.m2/repository/, https://libraries.minecraft.net/]
  GradleVariantHack:  true
  Disable Gradle:     false
  Stub Jars:          false

Processing Minecraft dependency: net.minecraft:joined:26.1-snapshot-11
downloadLauncherManifest
downloadVersionJson[26.1-snapshot-11]

[Incubating] Problems report is available at: file:///C:/Users/oscar/Documents/Projects/ModuleLoader/build/reports/problems/problems-report.html
7 actionable tasks: 7 up-to-date
Exception in thread "main" java.lang.IllegalStateException: Can not process net.minecraft:joined:26.1-snapshot-11 as it does not have a MCPConfig ror official mappings
	at net.minecraftforge.mcmaven.impl.MinecraftMaven.createMinecraft(MinecraftMaven.java:237)
	at net.minecraftforge.mcmaven.impl.MinecraftMaven.run(MinecraftMaven.java:131)
	at net.minecraftforge.mcmaven.cli.MavenTask.run(MavenTask.java:193)
	at net.minecraftforge.mcmaven.cli.Main.run(Main.java:63)
	at net.minecraftforge.mcmaven.cli.Main.main(Main.java:23)

A couple of typos in the error message as well but minor in the grand scheme of things.

This is with:

• the dep implementation minecraft.dependency('net.minecraft:joined:26.1-snapshot-11')
• mappings explicitly set to mappings channel: 'official', version: '26.1-snapshot-11'
  • Mojang does not provide any mappings for 26.1 as it is no longer obfuscated, but mappings are required to be explicitly set otherwise I get a different error, so I made an educated guess. Possibly [7.0] Add defaults for mappings ForgeGradle#1041 will solve this?

Note that 26.1 is slated for Q1 of 2026, which ends on the 31st of this month.

[Jonathing]

Please move this issue to MinecraftForge/MinecraftMavenizer, thank you.

[PaintNinja]

Reopening with a minimal reproduction case as this appears to be incomplete. FG7cleandev.zip

1. Attempting to use the joined artifact fails:

> Configure project :
Minecraft Mavenizer 0.4.41 by Forge Development LLC
Exception in thread "main"   Output:             C:\Users\oscar\Documents\Projects\FG7cleandev\.gradle\mavenizer\repo
  Output JSON:        C:\Users\oscar\Documents\Projects\FG7cleandev\.gradle\mavenizer\dependencies\default.json
java.lang.IllegalArgumentException: MCPConfigRepo does not support artifact: net.minecraft:joined:26.1-snapshot-11
        at net.minecraftforge.mcmaven.impl.repo.mcpconfig.MCPConfigRepo.processWithoutMcp(MCPConfigRepo.java:224)
        at net.minecraftforge.mcmaven.impl.MinecraftMaven.createMinecraft(MinecraftMaven.java:236)
        at net.minecraftforge.mcmaven.impl.MinecraftMaven.run(MinecraftMaven.java:132)
  Dependencies Only:  false
  Cache:              C:\Users\oscar\.gradle\caches\minecraftforge\forgegradle\mavenizer\caches
  JDK Cache:          C:\Users\oscar\.gradle\caches\minecraftforge\forgegradle\mavenizer\caches
        at net.minecraftforge.mcmaven.cli.MavenTask.run(MavenTask.java:208)
        at net.minecraftforge.mcmaven.cli.Main.run(Main.java:63)
  Offline:            false
  Cache Only:         false
  Ignore Cache:       false
        at net.minecraftforge.mcmaven.cli.Main.main(Main.java:23)
  Mappings:           official
  Foreign Repos:      [https://repo.maven.apache.org/maven2/, https://maven.minecraftforge.net/, https://libraries.minecraft.net/]
  GradleVariantHack:  true
  Disable Gradle:     false
  Stub Jars:          false

Processing Minecraft dependency: net.minecraft:joined:26.1-snapshot-11
downloadLauncherManifest
downloadVersionJson[26.1-snapshot-11]

2. Attempting to execute the runClient task with the client artifact fails:

> Configure project :
Minecraft Maven is up-to-date, took 0:00.586
Mavenizer did not output expected json data patcher.modules, Make sure you're using Mavenizer >= 0.4.33
Mavenizer did not output expected json data patcher.modules, Make sure you're using Mavenizer >= 0.4.33

1 problem was found storing the configuration cache.
- Task `:slimeLauncherMetadataForNetMinecraftClient` of type `net.minecraftforge.gradle.internal.SlimeLauncherMetadata`: error writing value of type 'org.gradle.api.internal.file.collections.DefaultConfigurableFileCollection'

See the complete report at file:///C:/Users/oscar/Documents/Projects/FG7cleandev/build/reports/configuration-cache/40fapuunm7hgvyiiu5znzrynd/9wbosz900ggwxf8uw8347iews/configuration-cache-report.html

[Incubating] Problems report is available at: file:///C:/Users/oscar/Documents/Projects/FG7cleandev/build/reports/problems/problems-report.html

FAILURE: Build failed with an exception.

* What went wrong:
Configuration cache state could not be cached: field `__metadata__` of task `:slimeLauncherMetadataForNetMinecraftClient` of type `net.minecraftforge.gradle.internal.SlimeLauncherMetadata`: error writing value of type 'org.gradle.api.internal.file.collections.DefaultConfigurableFileCollection'
> Could not resolve all files for configuration ':detachedConfiguration2'.
   > Could not resolve net.minecraft:client:26.1-snapshot-11.
     Required by:
         root project 'FG7cleandev'
      > No matching variant of net.minecraft:client:26.1-snapshot-11 was found. The consumer was configured to find a component for use during 'metadata' but:
          - Variant 'compile':
              - Incompatible because this component declares a component for use during compile-time and the consumer needed a component for use during 'metadata'
          - Variant 'enforced-platform-compile':
              - Incompatible because this component declares a component for use during compile-time and the consumer needed a component for use during 'metadata'
          - Variant 'enforced-platform-runtime':
              - Incompatible because this component declares a component for use during runtime and the consumer needed a component for use during 'metadata'
          - Variant 'javadoc':
              - Incompatible because this component declares a component for use during runtime and the consumer needed a component for use during 'metadata'
          - Variant 'platform-compile':
              - Incompatible because this component declares a component for use during compile-time and the consumer needed a component for use during 'metadata'
          - Variant 'platform-runtime':
              - Incompatible because this component declares a component for use during runtime and the consumer needed a component for use during 'metadata'
          - Variant 'runtime':
              - Incompatible because this component declares a component for use during runtime and the consumer needed a component for use during 'metadata'
          - Variant 'sources':
              - Incompatible because this component declares a component for use during runtime and the consumer needed a component for use during 'metadata'

* Try:
> No matching variant errors are explained in more detail at https://docs.gradle.org/9.3.1/userguide/variant_model.html#sub:variant-no-match.
> Review the variant matching algorithm at https://docs.gradle.org/9.3.1/userguide/variant_attributes.html#sec:abm_algorithm.
> Run with --stacktrace option to get the stack trace.

[LexManos]

Correct, there is no Joined artifact for versions that do not have MCPConfig so 1) failing is expected behavior

Same goes for there not being any metadata artifact.
Tho would need to defer to @Jonathing about the metadata artifact. I could generate a empty one to make FG happy. But ideally it would be fine not finding an artifact.

[Jonathing]

Sure, I can write in logic in ForgeGradle 7 to ignore metadata artifact if it fails to locate. Though, this can cause inconsistent behavior for Forge/MCPConfig-based versions. A metadata stub would fix that. Although, I think the metadata zip for the MCPConfig-based versions contains the default main/server classes for client and server runs, but correct me if I'm wrong.

[LexManos]

Just checked, literally the only thing in the MCPConfig based artifacts metadata zip is version.properties and /minecraft/version.json
So no, run configs/main are not included.
MCPConfig does not define those values, only UserdevConfig does.