fix: explain updates that keep the same version number

CHANGELOG.md

@@ -6,6 +6,11 @@ All notable changes to ModShift are documented here. The format follows
 
 ## [Unreleased]
 
+### Fixed
+
+- An update that keeps the same version number (a file rebuilt for the target Minecraft
+  version, e.g. `3.3.6 → 3.3.6`) is now explained in the report instead of looking like an error.
+
 ## [0.1.0] - 2026-10-20
 
 First public version.

README.md

@@ -71,7 +71,7 @@ https://neyordev.github.io/ModShift/ once GitHub Pages is enabled.
 ModShift needs **Node.js 20.17+ or 22.13+**.
 
 ```bash
-# From npm 
+# From npm
 npm install --global modshift
 
 # From source

docs/guide/installation.md

@@ -5,7 +5,7 @@
 ModShift needs **Node.js 20.17+ or 22.13+**.
 
 ```bash
-# From npm (once published)
+# From npm
 npm install --global modshift
 
 # From source

src/core/engine.ts

@@ -328,6 +328,7 @@ export async function analyzePack(
         reason: joinReasons(
           idNote,
           change && loaderChangeReason(change),
+          current && rebuildReason(current, best, target),
           fallback && fallbackReason(fallback, target),
         ),
       });
@@ -496,6 +497,18 @@ async function searchReplacements(
   return result;
 }
 
+// Même numéro de version, autre fichier : l'auteur publie un fichier par version de Minecraft
+// (ex. 1.13.2 pour 26.2 puis 1.13.2 pour 26.3). Sans cette précision, « 1.13.2 → 1.13.2 »
+// ressemble à une erreur.
+function rebuildReason(
+  current: ModrinthVersion,
+  best: ModrinthVersion,
+  target: MigrationTarget,
+): string | undefined {
+  if (current.id === best.id || current.version_number !== best.version_number) return undefined;
+  return `Same version number, file built for Minecraft ${target.minecraftVersion}.`;
+}
+
 function compatLayerReason(hint: CompatLayerHint): string {
   return `Its ${getLoader(hint.runs as Loader).name} version could run through ${hint.name} (${COMPAT_LAYER_NOTE}; not added to the pack).`;
 }

test/core/rebuild.test.ts

@@ -0,0 +1,88 @@
+import { describe, expect, it } from 'vitest';
+import { analyzePack } from '../../src/core/engine.js';
+import type { ModrinthVersion } from '../../src/modrinth/types.js';
+import type { ModPack } from '../../src/types.js';
+import { renderTable } from '../../src/report/table.js';
+import { createFakeClient, loadCatalog } from '../helpers/fakeModrinth.js';
+
+// Cas réel : Packet Fixer, Stella, SkyOcean… publient « 3.3.6 » pour 26.2 puis un autre fichier
+// « 3.3.6 » pour 26.3. Le rapport affichait « 3.3.6 → 3.3.6 » sans explication.
+function version(id: string, number: string, gameVersion: string, hash: string): ModrinthVersion {
+  return {
+    id,
+    project_id: 'REBUILD1',
+    name: id,
+    version_number: number,
+    game_versions: [gameVersion],
+    loaders: ['fabric'],
+    version_type: 'release',
+    date_published: '2024-09-01T00:00:00Z',
+    dependencies: [],
+    status: 'listed',
+    files: [
+      {
+        hashes: { sha1: hash.repeat(20), sha512: hash.repeat(64) },
+        url: `https://cdn.modrinth.com/data/fixture/${id}.jar`,
+        filename: `${id}.jar`,
+        primary: true,
+        size: 1000,
+      },
+    ],
+  };
+}
+
+function catalog() {
+  const base = loadCatalog();
+  base.projects.push({
+    id: 'REBUILD1',
+    slug: 'rebuild-mod',
+    title: 'Rebuild Mod',
+    description: 'A mod republished for each Minecraft version.',
+    categories: ['utility'],
+    project_type: 'mod',
+    loaders: ['fabric'],
+    game_versions: ['1.20.1', '1.21.1'],
+    downloads: 1000,
+  });
+  base.versions.push(
+    version('v1rebuild-old', '3.3.6', '1.20.1', 'c3'),
+    version('v1rebuild-new', '3.3.6', '1.21.1', 'c4'),
+  );
+  return base;
+}
+
+const pack: ModPack = {
+  source: 'mrpack',
+  minecraftVersion: '1.20.1',
+  loader: 'fabric',
+  mods: [
+    {
+      fileName: 'rebuild-mod-3.3.6.jar',
+      path: 'mods/rebuild-mod-3.3.6.jar',
+      origin: 'index',
+      hashes: { sha1: 'c3'.repeat(20) },
+      metadata: [],
+    },
+  ],
+  otherFiles: [],
+  warnings: [],
+};
+
+describe('same version number rebuilt for the target', () => {
+  it('explains an update that keeps the version number', async () => {
+    const { client } = createFakeClient(catalog());
+    const result = await analyzePack(
+      pack,
+      { minecraftVersion: '1.21.1', loader: 'fabric' },
+      client,
+    );
+    const mod = result.mods[0];
+    expect(mod).toMatchObject({
+      status: 'update-found',
+      currentVersion: { id: 'v1rebuild-old', versionNumber: '3.3.6' },
+      targetVersion: { id: 'v1rebuild-new', versionNumber: '3.3.6' },
+      reason: 'Same version number, file built for Minecraft 1.21.1.',
+    });
+    expect(renderTable(result)).toContain('Same version number, file built for Minecraft 1.21.1.');
+  });
+});