Run extra validation for Parchment versions, fixes #988

Copies `ParchmentVersion` from Mavenizer, for now.

Author: Jonathing

src/main/java/net/minecraftforge/gradle/internal/MinecraftMappingsImpl.java

@@ -21,7 +21,10 @@ abstract class MinecraftMappingsImpl implements MinecraftMappingsInternal {
     public MinecraftMappingsImpl(String channel, String version) {
         var problems = this.getObjects().newInstance(ForgeGradleProblems.class);
         this.channel = Util.checkMappingsParam(problems, channel, "channel");
-        this.version = Util.checkMappingsParam(problems, version, "version");
+        if (this.channel.equals("parchment"))
+            this.version = ParchmentVersion.parse(Util.checkMappingsParam(problems, version, "version")).toFriendly();
+        else
+            this.version = Util.checkMappingsParam(problems, version, "version");
     }
 
     @Override

src/main/java/net/minecraftforge/gradle/internal/ParchmentVersion.java

@@ -0,0 +1,152 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+package net.minecraftforge.gradle.internal;
+
+import org.jspecify.annotations.NullUnmarked;
+
+import java.util.regex.Pattern;
+
+@NullUnmarked
+record ParchmentVersion(
+    String timestamp,
+    /* @Nullable */ String mcVersion,
+    /* @Nullable */ String mapMcVersion
+) {
+    private static final Pattern TIMESTAMP = Pattern.compile("\\d{4}.\\d{2}.\\d{2}");
+    private static final Pattern MCP_TIMESTAMP = Pattern.compile("\\d{8}.\\d{6}");
+
+    // Parchment related things
+    public static final String PARCHMENT_MAVEN = "https://maven.parchmentmc.org/";
+    private static final String PARCHMENT_GROUP = "org.parchmentmc.data"; // Name is "parchment-{mcversion}'
+
+    /**
+     * <pre>
+     * Parchment names can be specified in many variants, including some 'shorthand's
+     * Basing this implementation on https://parchmentmc.org/docs/getting-started
+     *
+     * Namely, (in case they change the site)
+     *
+     * For using Parchment on the same version of Minecraft:
+     *    YYYY.MM.DD-&lt;Environment MC version>
+     *    Examples:
+     *      2021.12.12-1.17.1 for Minecraft 1.17.1
+     *      2022.08.07-1.18.2 for Minecraft 1.18.2
+     *      2022.08.14-1.19.2 for Minecraft 1.19.2
+     *
+     * For using Parchment for an older version on a newer MC version
+     * 	  &lt;Mapping's MC version>-YYYY.MM.DD-&lt;Environment MC version>
+     *	  Examples:
+     *      1.17.1-2021.12.12-1.18
+     *          Minecraft 1.17.1 mappings (2021.12.12-1.17.1) in an MC 1.18 environment
+     *      1.18.2-2022.08.07-1.19.1
+     *          Minecraft 1.18.2 mappings (2021.08.07-1.18.2) in an MC 1.19.1 environment
+     *      1.19.2-2022.08.14-1.20
+     *          Minecraft 1.19.2 mappings (2021.08.14-1.19.2) in an MC 1.20 environment
+     *
+     * Parchment also publishes 'snapshots', These are not supported by MCMaven, and as such will
+     * throw an exception during parsing.
+     *     Example:
+     *       parchment-1.21.9/2025.10.05-nightly-SNAPSHOT
+     *       parchment-1.16.5/BLEEDING-SNAPSHOT
+     * They have also published two known versions that don't follow the standard format. And I don't feel like supporting it.
+     *     parchment-1.16.5/20210607-SNAPSHOT
+     *     parchment-1.16.5/20210608-SNAPSHOT
+     *
+     * Tho undocumented, the implementation of Parchment's FG6 plugin supported specifying the MCP timestamp as part of the Environment MC version
+     * https://github.com/ParchmentMC/Librarian/blob/c7f9878feb76d210aa65569fe38cad5297f439c5/src/main/java/org/parchmentmc/librarian/forgegradle/ParchmentMappingVersion.java#L52
+     *
+     * In addition to the above formats I DO support not specifying a Minecraft version. It will need to be filled in later
+     * to find the correct download, but typically we can pull it from MCPConfig/other context.
+     *
+     * Note: This does not do any case sanitization
+     *
+     * @throws IllegalArgumentException if the version fails to parse
+     */
+    public static ParchmentVersion parse(String version) {
+        if (version == null)
+            throw new IllegalArgumentException("Parchment mappings version must be present");
+
+    	if (version.contains("-SNAPSHOT"))
+            throw new IllegalArgumentException("Parchment snapshots are not supported: " + version);
+
+    	var matcher = TIMESTAMP.matcher(version);
+    	if (!matcher.find())
+            throw new IllegalArgumentException("Parchment version does not contain a timestamp: " + version);
+
+    	int start = matcher.start();
+    	int end = matcher.end();
+
+    	// Simple case, we just specify the timestamp
+    	if (start == 0 && end == version.length())
+    		return new ParchmentVersion(version, null, null);
+
+		var timestamp = matcher.group();
+    	String mcVersion = null;
+
+    	// Minecraft Version is specified
+    	if (end < version.length()) {
+    		if (version.charAt(end) != '-' || end == version.length() - 1)
+    			throw new IllegalArgumentException("Parchment version does not specify Minecraft version: " + version);
+    		mcVersion = version.substring(end + 1);
+    	}
+
+    	// Default mapping version is the same as mc version
+    	var mapMcVersion = stripMcp(mcVersion);
+
+    	// Mappings MC version is specified
+    	if (start > 0) {
+    		if (version.charAt(start - 1) != '-' || start == 1)
+    			throw new IllegalArgumentException("Parchment version does not specify Mapping Minecraft version: " + version);
+    		mapMcVersion = version.substring(0, start - 1);
+    	}
+
+    	return new ParchmentVersion(timestamp, mcVersion, mapMcVersion);
+    }
+
+    /**
+     * Variant of {@link #parse(String)} that returns null instead of throwing IllegalArgumentException
+     */
+    public static ParchmentVersion tryParse(String version) {
+    	try {
+    		return parse(version);
+    	} catch (IllegalArgumentException e) {
+    		return null;
+    	}
+    }
+
+	// Remove MCP timestamp if its on there.
+    private static String stripMcp(String version) {
+    	if (version == null)
+    		return null;
+    	if (version.length() <= 17 || version.charAt(version.length() - 16) != '-')
+    		return version;
+
+    	var matcher = MCP_TIMESTAMP.matcher(version);
+    	if (matcher.find() && matcher.start() == version.length() - 15)
+    		return version.substring(0, version.length() - 16);
+
+    	return version;
+    }
+
+    public ParchmentVersion withMinecraft(String mcVersion) {
+    	return new ParchmentVersion(timestamp, mcVersion, mapMcVersion == null ? mcVersion : mapMcVersion);
+    }
+
+    public String toFriendly() {
+    	if (mapMcVersion == null) {
+    		if (mcVersion == null)
+    			return timestamp;
+    		return timestamp + '-' + mcVersion;
+    	}
+
+    	if (mcVersion == null)
+    		return mapMcVersion + '-' + timestamp;
+
+    	if (mapMcVersion.equals(stripMcp(mcVersion)))
+    		return timestamp + '-' + mcVersion;
+
+    	return mapMcVersion + '-' + timestamp + '-' + mcVersion;
+    }
+}