Parse mod versions leniently like the game does

The mod portal "ApiVersion" enum was validated strictly when loading a
mod's info.json, which rejected versions the game itself accepts. Versions
are now normalised the same lenient way the game reads them: leading
whitespace is allowed, the major and minor are required, the patch is
optional, any trailing content is ignored, and numbers are read as integers.

This applies to both a mod's version and its factorio_version, validated by
a regex schema rather than the fixed enum. The enum is no longer used to
validate versions at all - the mod portal is the source of truth, so its
error is now surfaced when a version is unsupported. The known-version list
kept for the web interface fallback gains 2.1.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/ctl/src/commands_mod.ts

@@ -108,9 +108,13 @@ modCommands.add(new lib.Command({
 		},
 		control: Control
 	) {
+		const searchVersion = lib.normaliseGameVersion(String(args.factorioVersion));
+		if (searchVersion === undefined) {
+			throw new Error(`Invalid factorio version "${args.factorioVersion}"`);
+		}
 		let response = await control.send(new lib.ModSearchRequest(
 			args.query,
-			lib.normaliseApiVersion(args.factorioVersion as any),
+			lib.majorMinorVersion(searchVersion),
 			args.page,
 			args.pageSize,
 			args.sort,

packages/lib/src/ModStore.ts

@@ -5,7 +5,7 @@ import { Static } from "@sinclair/typebox";
 import { logger } from "./logging";
 import { downloadFile, safeOutputFile } from "./file_ops";
 import { ModPortalReleaseSchema, ModPortalDetailsSchema, ModNameVersionPair } from "./data/messages_mod";
-import { ModInfo, ModPack, FullVersion, ApiVersion, ModVersionEquality } from "./data";
+import { ModInfo, ModPack, FullVersion, PartialVersion, majorMinorVersion, ModVersionEquality } from "./data";
 
 export interface ModStoreEvents {
 	/** A stored mod was created, updated or deleted */
@@ -198,18 +198,29 @@ export default class ModStore extends events.EventEmitter<ModStoreEvents> {
 	private async downloadModsChunk(
 		mods: ModNameVersionPair[],
 		username: string, token: string,
-		factorioVersion: ApiVersion,
+		factorioVersion: PartialVersion,
 	) {
 		const url = new URL("https://mods.factorio.com/api/mods");
 		url.searchParams.set("page_size", "max");
-		url.searchParams.set("version", factorioVersion);
+		url.searchParams.set("version", majorMinorVersion(factorioVersion));
 		const response = await fetch(url, {
 			method: "POST",
 			body: new URLSearchParams({ namelist: mods.map(m => m.name).join(",") }),
 		});
 
 		if (response.status !== 200) {
-			throw Error(`Fetch: ${url} returned ${response.status} ${response.statusText}`);
+			// Surface the portal's own error (e.g. an unsupported version) rather
+			// than a generic status line.
+			let detail = `${response.status} ${response.statusText}`;
+			try {
+				const body = await response.json() as { message?: string };
+				if (body && typeof body.message === "string") {
+					detail = body.message;
+				}
+			} catch {
+				// Response body was not JSON; keep the status line.
+			}
+			throw new Error(`Mod portal request to ${url} failed: ${detail}`);
 		}
 
 		const modReleases = (await response.json() as ModsInfoResponse).results;
@@ -236,7 +247,7 @@ export default class ModStore extends events.EventEmitter<ModStoreEvents> {
 	 * @param factorioVersion - Factorio version to filter for (mods are not guaranteed to work between Middle versions)
 	 */
 	async downloadMods(
-		mods: ModNameVersionPair[], username: string, token: string, factorioVersion: ApiVersion = "1.1"
+		mods: ModNameVersionPair[], username: string, token: string, factorioVersion: PartialVersion = "1.1"
 	) {
 		const chunkSize = 500;
 		const futures: Promise<void>[] = [];

packages/lib/src/data/ModInfo.ts

@@ -8,10 +8,10 @@ import { findRoot } from "../zip_ops";
 import { ModRecord } from "./ModPack";
 
 import {
-	ApiVersion,
-	ApiVersionSchema,
-	FullVersion, FullVersionSchema, integerFullVersion,
+	FullVersion, integerFullVersion,
 	integerPartialVersion,
+	GameVersionSchema, normaliseGameVersion, majorMinorVersion,
+	PartialVersion,
 	ModVersionEquality,
 } from "./version";
 
@@ -175,7 +175,7 @@ export default class ModInfo {
 	 * Major version of Factorio this mod supports.
 	 * Sourced from info.json.
 	 */
-	factorioVersion = "0.12" as "0.12" | ApiVersion;
+	factorioVersion = "0.12" as PartialVersion;
 
 	/**
 	 * Integer representation of the factorioVersion
@@ -248,16 +248,17 @@ export default class ModInfo {
 	 */
 	isDeleted = false;
 
-	// Content of info.json found in mod files
+	// Content of info.json found in mod files. The version fields use the same
+	// lenient format the game accepts; they are normalised when read in fromJSON.
 	static infoJsonSchema = Type.Object({
 		"name": Type.String(),
-		"version": FullVersionSchema,
+		"version": GameVersionSchema,
 		"title": Type.String(),
 		"author": Type.String(),
 		"contact": Type.Optional(Type.String()),
 		"homepage": Type.Optional(Type.String()),
 		"description": Type.Optional(Type.String()),
-		"factorio_version": Type.Optional(ApiVersionSchema),
+		"factorio_version": Type.Optional(GameVersionSchema),
 		"dependencies": Type.Optional(Type.Array(Type.String())),
 	});
 
@@ -279,13 +280,25 @@ export default class ModInfo {
 
 		// info.json fields
 		if (json.name) { modInfo.name = json.name; }
-		if (json.version) { modInfo.version = json.version; }
+		if (json.version) {
+			const version = normaliseGameVersion(json.version);
+			if (version === undefined) {
+				throw new Error(`Invalid mod version "${json.version}"`);
+			}
+			modInfo.version = version;
+		}
 		if (json.title) { modInfo.title = json.title; }
 		if (json.author) { modInfo.author = json.author; }
 		if (json.contact) { modInfo.contact = json.contact; }
 		if (json.homepage) { modInfo.homepage = json.homepage; }
 		if (json.description) { modInfo.description = json.description; }
-		if (json.factorio_version) { modInfo.factorioVersion = json.factorio_version; }
+		if (json.factorio_version) {
+			const factorioVersion = normaliseGameVersion(json.factorio_version);
+			if (factorioVersion === undefined) {
+				throw new Error(`Invalid factorio_version "${json.factorio_version}"`);
+			}
+			modInfo.factorioVersion = majorMinorVersion(factorioVersion);
+		}
 
 		// Parse the dependencies
 		try {

packages/lib/src/data/messages_mod.ts

@@ -5,7 +5,8 @@ import { JsonString, jsonArray } from "./composites";
 
 import {
 	FullVersion, FullVersionSchema,
-	ApiVersion, ApiVersionSchema, normaliseApiVersion,
+	PartialVersion, PartialVersionSchema,
+	GameVersionSchema,
 	ModVersionEquality,
 } from "./version";
 
@@ -154,7 +155,7 @@ export class ModSearchRequest {
 
 	constructor(
 		public query: string,
-		public factorioVersion: ApiVersion,
+		public factorioVersion: PartialVersion,
 		public page: number,
 		public pageSize?: number,
 		public sort?: string,
@@ -163,7 +164,7 @@ export class ModSearchRequest {
 
 	static jsonSchema = Type.Object({
 		"query": Type.String(),
-		"factorioVersion": ApiVersionSchema,
+		"factorioVersion": PartialVersionSchema,
 		"page": Type.Integer(),
 		"pageSize": Type.Optional(Type.Integer()),
 		"sort": Type.Optional(Type.String()),
@@ -207,7 +208,7 @@ export class ModSearchRequest {
 export const ModPortalReleaseSchema = Type.Object({
 	version: FullVersionSchema,
 	// Match the structure from ModStore's ModRelease/ModDetails
-	info_json: Type.Object({ factorio_version: ApiVersionSchema }),
+	info_json: Type.Object({ factorio_version: GameVersionSchema }),
 	released_at: Type.String(), // ISO 8601 date string
 	download_url: Type.String(),
 	file_name: Type.String(),
@@ -236,12 +237,12 @@ export class ModPortalGetAllRequest {
 	static permission = "core.mod.search_portal" as const;
 
 	constructor(
-		public factorioVersion: ApiVersion,
+		public factorioVersion: PartialVersion,
 		public hide_deprecated?: boolean,
 	) { }
 
 	static jsonSchema = Type.Object({
-		"factorioVersion": ApiVersionSchema,
+		"factorioVersion": PartialVersionSchema,
 		"hide_deprecated": Type.Optional(Type.Boolean()),
 	});
 
@@ -385,12 +386,12 @@ export class ModPortalDownloadRequest {
 
 	constructor(
 		public mods: ModNameVersionPair[],
-		public factorioVersion: ApiVersion,
+		public factorioVersion: PartialVersion,
 	) { }
 
 	static jsonSchema = Type.Object({
 		"mods": Type.Array(ModNameVersionPairSchema),
-		"factorioVersion": ApiVersionSchema,
+		"factorioVersion": PartialVersionSchema,
 	});
 
 	static fromJSON(json: Static<typeof this.jsonSchema>) {
@@ -422,13 +423,13 @@ export class ModDependencyResolveRequest {
 
 	constructor(
 		public mods: ModDependency[],
-		public factorioVersion: ApiVersion,
+		public factorioVersion: PartialVersion,
 		public checkForUpdates: boolean = false,
 	) { }
 
 	static jsonSchema = Type.Object({
 		"mods": Type.Array(ModDependency.jsonSchema),
-		"factorioVersion": ApiVersionSchema,
+		"factorioVersion": PartialVersionSchema,
 		"checkForUpdates": Type.Boolean(),
 	});
 
@@ -441,7 +442,7 @@ export class ModDependencyResolveRequest {
 		return new this(
 			[...modPack.mods.values()]
 				.map(mod => new ModDependency(`${mod.name} ${equality} ${mod.version}`)),
-			normaliseApiVersion(modPack.factorioVersion),
+			modPack.factorioVersion,
 			checkForUpdates,
 		);
 	}
@@ -452,7 +453,7 @@ export class ModDependencyResolveRequest {
 			[...modPack.mods.values()]
 				.filter(mod => mod.enabled)
 				.map(mod => new ModDependency(`${mod.name} ${equality} ${mod.version}`)),
-			normaliseApiVersion(modPack.factorioVersion),
+			modPack.factorioVersion,
 			checkForUpdates,
 		);
 	}

packages/lib/src/data/version.ts

@@ -24,25 +24,11 @@ export function isVersionEquality(input: string): input is VersionEquality {
 }
 
 /**
- * Matches valid factorio versions accepts by the web API
- * https://wiki.factorio.com/Mod_portal_API#/api/mods (see version enum)
+ * Known Factorio major versions, offered as fallback options in the web
+ * interface before the live version list has been fetched. Versions are no
+ * longer validated against this list; the mod portal is the source of truth.
  */
-export const ApiVersions = ["0.13", "0.14", "0.15", "0.16", "0.17", "0.18", "1.0", "1.1", "2.0"] as const;
-export const ApiVersionSchema = Type.Union(ApiVersions.map(v => Type.Literal(v)));
-export type ApiVersion = Static<typeof ApiVersionSchema>;
-
-export function isApiVersion(input: string): input is ApiVersion {
-	return ApiVersions.includes(input as any);
-}
-
-export function normaliseApiVersion(version: PartialVersion) {
-	const parts = version.split(".");
-	const apiVersion = `${parts[0]}.${parts[1]}`;
-	if (!isApiVersion(apiVersion)) {
-		throw new Error(`Factorio version not supported by mod portal: ${apiVersion}`);
-	}
-	return apiVersion;
-}
+export const ApiVersions = ["0.13", "0.14", "0.15", "0.16", "0.17", "0.18", "1.0", "1.1", "2.0", "2.1"] as const;
 
 /**
  * Matches valid mod versions, where all parts are specified.
@@ -68,6 +54,31 @@ export function normaliseFullVersion(version: PartialVersion) {
 	return (parts.length === 3 ? version : `${version}.0`) as FullVersion;
 }
 
+/**
+ * Matches a version string the same lenient way the game reads it: each number
+ * may be preceded by whitespace, the major and minor are required, the patch is
+ * optional, and any trailing content is ignored. The pattern is intentionally
+ * not anchored at the end.
+ */
+const gameVersionRegExp = /^\s*\d+\.\s*\d+(?:\.\s*\d+)?/;
+export const GameVersionSchema = Type.String({ pattern: gameVersionRegExp.source });
+
+/**
+ * Normalise a version string the same lenient way the game reads it. Numbers
+ * are read as integers, so leading whitespace and zeros are dropped and any
+ * content after the patch is ignored.
+ *
+ * @returns The normalised full version, or undefined if no major and minor
+ *     could be read.
+ */
+export function normaliseGameVersion(input: string): FullVersion | undefined {
+	const match = /^\s*(\d+)\.\s*(\d+)(?:\.\s*(\d+))?/.exec(input);
+	if (match === null) {
+		return undefined;
+	}
+	return `${Number(match[1])}.${Number(match[2])}.${Number(match[3] ?? "0")}` as FullVersion;
+}
+
 /**
  * Matches valid factorio versions and mod dependencies specifications where 2 or 3 parts are specified.
  */
@@ -87,6 +98,14 @@ export function integerPartialVersion(version: PartialVersion) {
 	return major * 0x100000000 + minor * 0x10000 + (sub || 0) as IntegerVersion;
 }
 
+/**
+ * The major.minor of a version, as used by the mod portal's version filter.
+ */
+export function majorMinorVersion(version: PartialVersion) {
+	const [major, minor] = version.split(".");
+	return `${major}.${minor}` as `${number}.${number}`;
+}
+
 /**
  * Matches valid factorio target versions, this is the same as partial but also accepts "latest".
  */

packages/web_ui/src/components/ModPackViewPage.tsx

@@ -77,12 +77,12 @@ function SearchModsTable(props: SearchModsTableProps) {
 	const [modResultPageSize, setModResultPageSize] = useState<number>(10);
 	const [modResultCount, setModResultCount] = useState<number>(2);
 	const [modResultSelectedVersion, setModResultSelectedVersion] = useState<Map<string, number>>(new Map());
-	const [factorioVersion, setFactorioVersion] = useState<lib.ApiVersion | null>(null);
+	const [factorioVersion, setFactorioVersion] = useState<lib.PartialVersion | null>(null);
 
 	// Get a valid factorio version
 	useEffect(() => {
 		try {
-			setFactorioVersion(lib.normaliseApiVersion(props.modPack.factorioVersion));
+			setFactorioVersion(lib.majorMinorVersion(props.modPack.factorioVersion));
 		} catch (err) {
 			setFactorioVersion(null);
 		}
@@ -271,7 +271,7 @@ function DownloadDependenciesButton(props: DownloadDependenciesProps) {
 	const [open, setOpen] = useState(false);
 	const [error, setError] = useState<Error | null>(null);
 	const [loading, setLoading] = useState<boolean>(false);
-	const [factorioVersion, setFactorioVersion] = useState<lib.ApiVersion | null>(null);
+	const [factorioVersion, setFactorioVersion] = useState<lib.PartialVersion | null>(null);
 
 	const [mods, setMods] = useState<lib.ModInfo[]>([]); // All resolved mods and dependencies
 	const [missing, setMissing] = useState<lib.ModInfo[]>([]); // Missing mods and dependencies, excluding builtin
@@ -295,7 +295,7 @@ function DownloadDependenciesButton(props: DownloadDependenciesProps) {
 	// Get a valid factorio version
 	useEffect(() => {
 		try {
-			setFactorioVersion(lib.normaliseApiVersion(props.modPack.factorioVersion));
+			setFactorioVersion(lib.majorMinorVersion(props.modPack.factorioVersion));
 		} catch (err) {
 			setError(new Error(`Invalid factorio version: ${props.modPack.factorioVersion}`));
 			setFactorioVersion(null);
@@ -577,8 +577,8 @@ function ModsTable(props: ModsTableProps) {
 		if (mod.enabled && mod.info) {
 			mod.warning = mod.info.checkDependencySatisfaction(mods.filter(m => m.enabled));
 			try {
-				const packFactorioVersion = lib.normaliseApiVersion(props.modPack.factorioVersion);
-				const modFactorioVersion = lib.normaliseApiVersion(mod.info.factorioVersion);
+				const packFactorioVersion = lib.majorMinorVersion(props.modPack.factorioVersion);
+				const modFactorioVersion = lib.majorMinorVersion(mod.info.factorioVersion);
 				if (packFactorioVersion !== modFactorioVersion) {
 					mod.warning = "wrong_factorio_version";
 				}

packages/web_ui/src/components/ModsPage.tsx

@@ -147,7 +147,7 @@ function SearchModsButton() {
 	const [open, setOpen] = useState(false);
 	const [form] = Form.useForm();
 	const [searchText, setSearchText] = useState("");
-	const [factorioVersion, setFactorioVersion] = useState<lib.ApiVersion>("2.0");
+	const [factorioVersion, setFactorioVersion] = useState<lib.PartialVersion>("2.0");
 
 	// State for all mods fetched from backend
 	const [allMods, setAllMods] = useState<ModPortalModType[]>([]);
@@ -165,7 +165,7 @@ function SearchModsButton() {
 		modName: string,
 		modTitle: string | undefined,
 		modVersion: lib.FullVersion | undefined,
-		portalFactorioVersion: lib.ApiVersion,
+		portalFactorioVersion: lib.PartialVersion,
 	) => {
 		if (modVersion) {
 			control.send(
@@ -271,7 +271,7 @@ function SearchModsButton() {
 	// Update search text and factorio version from form
 	const handleSearch = (changedValues: any, allValues: any) => {
 		const nameValue = allValues.name;
-		const versionValue = allValues.factorioVersion as lib.ApiVersion | undefined;
+		const versionValue = allValues.factorioVersion as lib.PartialVersion | undefined;
 
 		// Only trigger state updates if values actually changed
 		if (nameValue !== searchText) {

test/lib/ModStore.test.js

@@ -358,7 +358,7 @@ describe("lib/ModStore", function () {
 
 			await assert.rejects(
 				modStore.downloadMods(modsToDownload, username, token, factorioVersion),
-				/Fetch: https:\/\/mods\.factorio\.com\/api\/mods.* returned 503 Service Unavailable/
+				/Mod portal request to https:\/\/mods\.factorio\.com\/api\/mods.* failed: 503 Service Unavailable/
 			);
 			assert.equal(modStore.files.size, 0, "No mods should be added on API error");
 		});

test/lib/data/ModInfo.js

@@ -341,6 +341,21 @@ describe("lib/data/ModInfo", function() {
 				dependencies: ["base", ""],
 			}), /my-mod/); // check the mod name is included in the error message
 		});
+		it("should normalise lenient version fields the way the game reads them", function() {
+			const mod = ModInfo.fromJSON({
+				name: "my-mod",
+				version: " 1.2.3-extra",
+				factorio_version: "1.1.0",
+			});
+			assert.equal(mod.version, "1.2.3");
+			assert.equal(mod.factorioVersion, "1.1");
+		});
+		it("should throw for an unparseable mod version", function() {
+			assert.throws(
+				() => ModInfo.fromJSON({ name: "my-mod", version: "not-a-version" }),
+				/Invalid mod version/
+			);
+		});
 		it("should sort integer mod versions lexicographically", function() {
 			let unsortedVersions = ["1.0.0", "1.1.0", "0.1.0", "3.0.0", "1.2.0", "0.3.1", "0.3.3", "2.1.1", "0.0.1"];
 			let sortedVersions = ["0.0.1", "0.1.0", "0.3.1", "0.3.3", "1.0.0", "1.1.0", "1.2.0", "2.1.1", "3.0.0"];

test/lib/data/version.test.js

@@ -17,36 +17,33 @@ describe("lib/data/version", function() {
 			}
 		});
 	});
-	describe("isApiVersion()", function() {
-		it("should correctly validate input strings", function() {
-			const valid = ["0.13", "0.14", "0.15", "0.16", "0.17", "0.18", "1.0", "1.1", "2.0"];
-			for (const test of valid) {
-				assert.equal(lib.isApiVersion(test), true, test);
-			}
-			const invalid = ["0.12", "0.19", "1.2", "2.1", "1.0.0", "1.0.0.0", "0", "", "latest"];
+	describe("normaliseGameVersion()", function() {
+		it("should normalise lenient version strings the way the game reads them", function() {
+			// Major and minor required, patch optional and defaulting to 0.
+			assert.equal(lib.normaliseGameVersion("1.1"), "1.1.0");
+			assert.equal(lib.normaliseGameVersion("1.1.50"), "1.1.50");
+			assert.equal(lib.normaliseGameVersion("0.18"), "0.18.0");
+			// Leading whitespace and zeros are dropped.
+			assert.equal(lib.normaliseGameVersion("  1.1"), "1.1.0");
+			assert.equal(lib.normaliseGameVersion("01.02.03"), "1.2.3");
+			assert.equal(lib.normaliseGameVersion("1. 1. 50"), "1.1.50");
+			// Anything after the patch (or a non-numeric patch) is ignored.
+			assert.equal(lib.normaliseGameVersion("1.1.50-beta"), "1.1.50");
+			assert.equal(lib.normaliseGameVersion("1.1.x"), "1.1.0");
+			assert.equal(lib.normaliseGameVersion("1.1.50.60"), "1.1.50");
+		});
+		it("should return undefined when no major.minor can be read", function() {
+			const invalid = ["1", "", "latest", "abc", ".1.1", "x.y"];
 			for (const test of invalid) {
-				assert.equal(lib.isApiVersion(test), false, test);
+				assert.equal(lib.normaliseGameVersion(test), undefined, test);
 			}
 		});
 	});
-	describe("normaliseApiVersion()", function() {
-		it("should normalise accepted versions", function() {
-			assert.equal(lib.normaliseApiVersion("0.13"), "0.13");
-			assert.equal(lib.normaliseApiVersion("0.13.0"), "0.13");
-			assert.equal(lib.normaliseApiVersion("0.13.1"), "0.13");
-			assert.equal(lib.normaliseApiVersion("1.1"), "1.1");
-			assert.equal(lib.normaliseApiVersion("1.1.0"), "1.1");
-			assert.equal(lib.normaliseApiVersion("1.1.1"), "1.1");
-			assert.equal(lib.normaliseApiVersion("2.0"), "2.0");
-			assert.equal(lib.normaliseApiVersion("2.0.0"), "2.0");
-			assert.equal(lib.normaliseApiVersion("2.0.1"), "2.0");
-			assert.equal(lib.normaliseApiVersion("1.0.0.0"), "1.0");
-		});
-		it("should throw for invalid versions", function() {
-			const invalid = ["0.12", "0", "", "latest"];
-			for (const test of invalid) {
-				assert.throws(() => lib.normaliseApiVersion(test), undefined, test);
-			}
+	describe("majorMinorVersion()", function() {
+		it("should return the major.minor", function() {
+			assert.equal(lib.majorMinorVersion("1.1"), "1.1");
+			assert.equal(lib.majorMinorVersion("1.1.50"), "1.1");
+			assert.equal(lib.majorMinorVersion("0.18.0"), "0.18");
 		});
 	});
 	describe("isFullVersion()", function() {