Merge pull request 'Version port script and compile check for pull requests' (#19) from port-tooling into master

Reviewed-on: #19

.gitea/workflows/check.yml

@@ -0,0 +1,31 @@
+name: Check
+
+# Compiles every Minecraft version on pull requests and on pushes to master,
+# so a change that breaks one version (e.g. a missed or bad port) fails before
+# it's merged instead of in the release build.
+on:
+  pull_request:
+  push:
+    branches: [master]
+
+jobs:
+  compile:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          submodules: true
+
+      - name: Set up Java 21
+        uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: 21
+          cache: gradle
+
+      - name: Compile all versions
+        run: |
+          chmod +x gradlew
+          # --continue reports every version that fails, not just the first.
+          ./gradlew compileJava --no-daemon --stacktrace --continue

VERSION_GUIDE.md

@@ -1,3 +1,44 @@
 # Version guide
 
-This guide will help you to add or edit minecraft versions.
+How Saturn Client supports several Minecraft versions, and how to change or add one.
+
+## Layout
+
+- `common/`: all version-independent code (mods, UI, cosmetics, the server client). It has no Minecraft dependency and reaches the game only through the interfaces in `org.saturnclient.common`.
+- `versions/<mc>/`: one module per Minecraft version, implementing those interfaces (providers, refs, mixins). Each is a full copy, and they differ only where Minecraft's API differs.
+  - `gradle.properties`: the Minecraft, Yarn, Fabric Loader and Fabric API versions.
+  - `src/`: the version-specific code and the three mixin configs.
+
+`settings.gradle` includes every folder under `versions/` automatically, as the Gradle project `:mc-<mc>`.
+
+## Porting a change to the other versions
+
+Make the change in one version, usually the newest, then run:
+
+```sh
+scripts/port.sh                        # port uncommitted changes to every other version
+scripts/port.sh --dry-run              # see what would apply cleanly first
+scripts/port.sh --to 1.21.9,1.21.10    # only some versions
+scripts/port.sh --commit <rev>         # port what a commit changed instead
+```
+
+The script applies the diff under `versions/<from>/src` to each other version with `git apply --3way`:
+
+- **applied**: the files matched, and nothing else is needed.
+- **CONFLICTS**: that version's code really differs. The file gets normal conflict markers, with the version's own code in `ours` and the ported change in `theirs`. Adapt the change to that version's API and resolve.
+- **already has this change**: nothing to do, which is safe to see when re-running.
+
+Only `src/` is ported. `build.gradle` and `gradle.properties` are version-specific on purpose. Then build everything:
+
+```sh
+./gradlew compileJava
+```
+
+The **Check** workflow runs the same compile on every pull request, so a version that was missed or mis-ported fails before merging.
+
+## Adding a Minecraft version
+
+1. Copy the closest existing version: `cp -r versions/1.21.11 versions/<new>`. Delete its `build/`, `.gradle/` and `run/` folders if present.
+2. In `versions/<new>/gradle.properties`, set `minecraft_version`, `yarn_mappings`, `loader_version` and `fabric_api_version`. The right values are listed at <https://fabricmc.net/develop>.
+3. Build it with `./gradlew :mc-<new>:compileJava` and fix what Minecraft changed. Check the mixin configs in `src/main/resources/*.mixins.json` as well: a mixin whose target changed fails at startup, not at compile time, so launch it with `./gradlew :mc-<new>:runClient`.
+4. The release workflow builds every folder under `versions/`, and "Publish to Modrinth" takes the game version from each jar's name, so neither needs changing.

scripts/port.sh

@@ -0,0 +1,156 @@
+#!/usr/bin/env bash
+# Port a change made in one Minecraft version's code to the other versions.
+#
+# Takes the diff under versions/<from>/src and applies it to versions/<to>/src
+# with `git apply --3way`: it applies cleanly where the files match, and leaves
+# normal merge conflicts only where a version really differs. Only src/ is
+# ported; build.gradle and gradle.properties are version-specific on purpose.
+#
+# Usage:
+#   scripts/port.sh [--from VERSION] [--to V1,V2,...] [--commit REV] [--dry-run]
+#
+#   --from      version the change was made in. Default: the only version with
+#               uncommitted changes (or changed by --commit).
+#   --to        comma-separated versions to port to. Default: all others.
+#   --commit    port the changes a commit made instead of uncommitted changes.
+#   --dry-run   report what would happen without changing anything.
+#
+# Exit status: 0 if every version applied cleanly (or already had the change),
+# 1 if any version has conflicts or failed.
+
+set -euo pipefail
+
+cd "$(git rev-parse --show-toplevel)"
+
+from=""
+to=""
+commit=""
+dry_run=false
+
+while [ $# -gt 0 ]; do
+    case "$1" in
+        --from) from="$2"; shift 2 ;;
+        --to) to="$2"; shift 2 ;;
+        --commit) commit="$2"; shift 2 ;;
+        --dry-run) dry_run=true; shift ;;
+        -h|--help) sed -n '2,20p' "$0" | sed 's/^# \{0,1\}//'; exit 0 ;;
+        *) echo "Unknown option: $1 (see --help)" >&2; exit 2 ;;
+    esac
+done
+
+all_versions=$(ls -d versions/*/ | xargs -n1 basename | sort -t. -k1,1n -k2,2n -k3,3n)
+
+version_exists() {
+    [ -d "versions/$1/src" ]
+}
+
+# Versions with changes, from the working tree or from the given commit.
+changed_versions() {
+    if [ -n "$commit" ]; then
+        git show --name-only --format= "$commit" -- versions/
+    else
+        git diff HEAD --name-only -- versions/
+        git ls-files --others --exclude-standard -- versions/
+    fi | sed -n 's#^versions/\([^/]*\)/src/.*#\1#p' | sort -u
+}
+
+if [ -z "$from" ]; then
+    candidates=$(changed_versions)
+    count=$(printf '%s\n' "$candidates" | grep -c . || true)
+    if [ "$count" -ne 1 ]; then
+        echo "Changes found in ${count} versions (${candidates//$'\n'/, }); pass --from to choose one." >&2
+        exit 2
+    fi
+    from="$candidates"
+fi
+
+version_exists "$from" || { echo "No such version: $from" >&2; exit 2; }
+
+if [ -z "$to" ]; then
+    to=$(printf '%s\n' $all_versions | grep -vx "$from" | paste -sd, -)
+fi
+
+# New files are only included in `git diff HEAD` once git knows about them.
+if [ -z "$commit" ]; then
+    untracked=$(git ls-files --others --exclude-standard -- "versions/$from/src")
+    if [ -n "$untracked" ]; then
+        if $dry_run; then
+            echo "note: new files in versions/$from/src are untracked and won't be ported in a dry run:" >&2
+            printf '  %s\n' $untracked >&2
+        else
+            printf '%s\n' "$untracked" | xargs git add --intent-to-add --
+        fi
+    fi
+fi
+
+# --full-index gives --3way the real blob ids to merge against.
+if [ -n "$commit" ]; then
+    patch=$(git show --full-index --binary --format= "$commit" -- "versions/$from/src")
+else
+    patch=$(git diff HEAD --full-index --binary -- "versions/$from/src")
+fi
+
+if [ -z "$patch" ]; then
+    echo "No changes under versions/$from/src to port." >&2
+    exit 2
+fi
+
+files=$(printf '%s\n' "$patch" | grep -c '^diff --git' || true)
+echo "Porting $files file(s) from $from${commit:+ (commit $commit)}"
+
+from_re=$(printf '%s' "$from" | sed 's/\./\\./g')
+tmp=$(mktemp -d)
+trap 'rm -rf "$tmp"' EXIT
+
+status=0
+IFS=',' read -r -a targets <<< "$to"
+
+for target in "${targets[@]}"; do
+    if [ "$target" = "$from" ]; then
+        continue
+    fi
+    if ! version_exists "$target"; then
+        printf '  %-8s  skipped: no such version\n' "$target"
+        status=1
+        continue
+    fi
+
+    # Point the patch's file headers at the target version.
+    printf '%s\n' "$patch" | sed -E "/^(diff --git |--- |\+\+\+ |rename (from|to) |copy (from|to) )/ s#versions/${from_re}/#versions/${target}/#g" > "$tmp/$target.patch"
+
+    if git apply --check --reverse "$tmp/$target.patch" 2>/dev/null; then
+        printf '  %-8s  already has this change\n' "$target"
+        continue
+    fi
+
+    if $dry_run; then
+        if git apply --check "$tmp/$target.patch" 2>/dev/null; then
+            printf '  %-8s  would apply cleanly\n' "$target"
+        else
+            printf '  %-8s  would need a 3-way merge (possible conflicts)\n' "$target"
+        fi
+        continue
+    fi
+
+    if output=$(git apply --3way "$tmp/$target.patch" 2>&1); then
+        printf '  %-8s  applied\n' "$target"
+    else
+        conflicts=$(git diff --name-only --diff-filter=U -- "versions/$target")
+        if [ -n "$conflicts" ]; then
+            printf '  %-8s  CONFLICTS in:\n' "$target"
+            printf '%s\n' "$conflicts" | sed 's/^/              /'
+        else
+            printf '  %-8s  FAILED:\n' "$target"
+            printf '%s\n' "$output" | sed 's/^/              /'
+        fi
+        status=1
+    fi
+done
+
+if ! $dry_run; then
+    echo
+    echo "Ported changes are staged in the target versions. Resolve any conflicts, then build"
+    echo "the affected versions, e.g. ./gradlew compileJava"
+fi
+
+exit $status