NeoForm

NeoForm provides steps to create reproducible and recompilable Minecraft source code.

Version Availability

Release versions of Minecraft are on the main branch. Development versions (snapshots, pre-releases) of Minecraft for an upcoming release version of Minecraft will be on a branch named <version>-dev to avoid bloating the main branch. For example, 1.21.9-dev for the snapshots and pre-releases leading up to 1.21.9.

How to Use

NeoForm has two hierarchies of Gradle projects:

• There is an outer Gradle build with many subprojects: mostly one per Minecraft version.
• There is an inner Gradle build for each Minecraft version, that is generated by the outer Gradle build when wanting to create or modify source patches for a version.

A typical workflow to change the patches would be:

• Run gradlew :<version>:projectApplyAll in the root directly (for example replace <version> by 1.21.8). This will run the outer Gradle build, to create a project with decompiled Minecraft sources in versions/release/<version>/projects.
• Open the generated inner build at versions/release/<version>/projects, for example with IntelliJ.
• Make any changes to the sources of each subproject, for example change joined/src/main/java/ in the inner build.
• Run gradlew :<version>:projectMakeAll in the root directory to update the patches. This will run the outer Gradle build, to generate patches from the changes you made in the inner build.

Definitions

• type can be either
  • release (release versions)
  • pre (pre-releases and release candidates)
  • snapshot (snapshots)
• ver is a major version of Minecraft without the ending .<minor_version> (e.g. the value for 1.21.1 is 1.21)
• version is a specific version of Minecraft

Local Settings

Options in local.properties can be set to filter for which versions are loaded by the (outer) Gradle build:

• type (defaults to release)
• ver (defaults to all major versions)

Gradle Tasks

• :<version>:projectApplyAll - Creates Minecraft source code of that version with patches applied
• :<version>:projectMakeAll - Generates patches for the specified version
• update - Requires old_version and new_version to be specified in gradle.properties in the format of <type>/<ver>/<version>. Sets up the new version based on the old version without the patches from the old version
• :<version>:testJdks - Checks that the generated source code is consistant across java versions along with compilation

GitHub Actions Variables

Some workflows need to know which release-version the current series of snapshots will result in.

We set the GitHub Actions variable TARGET_MC_VERSION for this purpose in the project settings.

If we suspect that the current series of snapshots will be released as Minecraft 1.21.2 for example, this variable should be set to 1.21.2.

GitHub Actions Workflows

• Check For New Snapshots - Runs every 30 minutes from 6am to 7pm UTC and checks for when Mojang releases a new version and runs the Update workflow
• Update - Runs the update task and checks for any library updates along with copying over the patches from the old version to the new version then attempts to run the Check workflow. Parameters:
  • Old branch - The branch name where the old version is
  • Old version - <type>/<ver>/<version> of the old version
  • Patches version (deprecated) - <type>/<ver>/<version> of the version to take the patches from (defaults to Old version)
  • New branch - The branch name of where the new version will be (defaults to Old branch)
  • New version - <type>/<ver>/<version> of the new version
  • Fix known error(s) in mapping file (deprecated) - Was used for when Jammer would generate incorrect names for fields or methods
  • Copy extras - When changing branches copy over files outside of the versions and .github directories
  • Publish - Passed to Check workflow
• Check - Required to run from the branch with the version being checked and checks if patches successfully apply and runs :<version>:testJdks and optionally publishes to the NeoForge maven. Parameters:
  • Version - <type>/<ver>/<version> of the version
  • Push changed patches - If enabled and running :<version>:projectApplyAll then :<version>:projectMakeAll changes patches then it pushes the updated patches
  • Publish whether to publish to the NeoForge maven

Mojang Mappings

This project uses the obfuscation logs provided by Mojang for Minecraft in order to generate its data. That means that the data here could be considered a derivative work of those mappings. So you should be fully versed in the license associated with those official mappings. You can read more about our interpretation of them here.