Allow custom modloader versions for auto curseforge (#3759)

Dockerfile

@@ -49,7 +49,7 @@ RUN easy-add --var os=${TARGETOS} --var arch=${TARGETARCH}${TARGETVARIANT} \
   --var version=${MC_SERVER_RUNNER_VERSION} --var app=mc-server-runner --file {{.app}} \
   --from ${GITHUB_BASEURL}/itzg/{{.app}}/releases/download/{{.version}}/{{.app}}_{{.version}}_{{.os}}_{{.arch}}.tar.gz
 
-ARG MC_HELPER_VERSION=1.50.6
+ARG MC_HELPER_VERSION=1.50.8
 ARG MC_HELPER_BASE_URL=${GITHUB_BASEURL}/itzg/mc-image-helper/releases/download/${MC_HELPER_VERSION}
 # used for cache busting local copy of mc-image-helper
 ARG MC_HELPER_REV=1

docs/types-and-platforms/mod-platforms/auto-curseforge.md

@@ -137,6 +137,30 @@ The following examples all refer to version 1.0.7 of ATM8:
 
 Pinning modpack version also pins the mod loader (to the version specified by the modpack). Mod loader version cannot be pinned independently of the modpack.
 
+### Custom modloader versions
+
+By default, AUTO_CURSEFORGE will use the exact modloader version declared by the modpack. However, you can override the modloader version by setting the following environment variable:
+
+- `CF_MOD_LOADER_VERSION`: Override the mod loader version (e.g., `43.4.22`)
+
+!!! example "Override mod loader version"
+
+    ```yaml
+    environment:
+      MODPACK_PLATFORM: AUTO_CURSEFORGE
+      CF_API_KEY: ${CF_API_KEY}
+      CF_SLUG: all-the-mods-8
+      CF_MOD_LOADER_VERSION: "43.4.22"
+    ```
+
+    ```title="Using docker run"
+    docker run -e CF_MOD_LOADER_VERSION=43.4.22 -e CF_SLUG=my-fabric-pack ...
+    ```
+
+!!! warning "Compatibility"
+
+    Using a custom modloader version that differs significantly from what the modpack was designed for may cause compatibility issues. Use this feature carefully and test thoroughly.
+
 ## Manual Downloads
 
 For mod, modpacks, and world files that are not allowed for automated download, the container path `/downloads` can be attached and matching files will be retrieved from there. The subdirectories `mods`, `modpacks`, and `worlds` will also be checked accordingly. To change the source location of downloaded files, set `CF_DOWNLOADS_REPO` to an existing container path. To disable this feature, set `CF_DOWNLOADS_REPO` to an empty string.

docs/variables.md

@@ -818,6 +818,12 @@ alternatively, you can mount: <code>/etc/localtime:/etc/localtime:ro
             <td><code>false</code></td>
             <td>⬜️</td>
         </tr>
+        <tr>
+            <td><code>CF_MOD_LOADER_VERSION</code></td>
+            <td>Override the mod loader version declared by the modpack</td>
+            <td><code></code></td>
+            <td>⬜️</td>
+        </tr>
     </tbody>
 </table>
 

examples/auto-curseforge/fabric-custom-loader/docker-compose.yml

@@ -0,0 +1,22 @@
+services:
+  mc:
+    image: itzg/minecraft-server
+    environment:
+      EULA: "TRUE"
+      MODPACK_PLATFORM: AUTO_CURSEFORGE
+      # Allocate API key from https://console.curseforge.com/
+      CF_API_KEY: ${CF_API_KEY}
+      # Example of overriding modloader version for a Fabric modpack
+      # Refer to https://docker-minecraft-server.readthedocs.io/en/latest/types-and-platforms/mod-platforms/auto-curseforge/#api-key
+      CF_SLUG: "cobblemon-fabric"
+      # Override the mod loader version from the modpack
+      CF_MOD_LOADER_VERSION: "0.16.14"
+      MEMORY: "4G"
+    ports:
+      - "25565:25565"
+    volumes:
+      - ./data:/data
+    stdin_open: true
+    tty: true
+
+# See https://docker-minecraft-server.readthedocs.io/en/latest/types-and-platforms/mod-platforms/auto-curseforge/#custom-modloader-versions

scripts/start-deployAutoCF

@@ -22,6 +22,7 @@ set -eu
 : "${CF_MODPACK_MANIFEST:=}"
 : "${CF_API_CACHE_DEFAULT_TTL:=}" # as ISO-8601 duration, such as P2D or PT12H
 : "${CF_API_KEY_FILE:=}" # Path to file containing CurseForge API key
+: "${CF_MOD_LOADER_VERSION:=}" # Override mod loader version
 
 resultsFile=/data/.install-curseforge.env
 
@@ -66,6 +67,7 @@ setArg --exclude-mods CF_EXCLUDE_MODS
 setArg --force-include-mods CF_FORCE_INCLUDE_MODS
 setArg --exclude-include-file CF_EXCLUDE_INCLUDE_FILE
 setArg --downloads-repo CF_DOWNLOADS_REPO
+setArg --mod-loader-version CF_MOD_LOADER_VERSION
 
 if ! mc-image-helper install-curseforge "${args[@]}"; then
     logError "Failed to auto-install CurseForge modpack"