never overwrite a fileName another writer set

src/index.ts

@@ -33,7 +33,7 @@ import type {
     ConfigureRequest,
     ConfigureResponse,
 } from './types.js';
-import { manifest, process as processFile } from './plugin.js';
+import { manifest, process as processFile, configure } from './plugin.js';
 
 const app = Fastify({ logger: true });
 let ready = false;
@@ -53,6 +53,7 @@ app.get('/manifest', async () => manifest);
 app.post<{ Body: ConfigureRequest }>('/configure', async (request): Promise<ConfigureResponse> => {
     try {
         pluginConfig = request.body.config || {};
+        configure(pluginConfig);
         console.log('[file-info] Configuration updated');
         return { status: 'ok' };
     } catch (error) {

src/plugin.ts

@@ -105,9 +105,57 @@ export const manifest: PluginManifest = {
             readonly: true,
         },
     },
-    config: {},
+    config: {
+        forceRecompute: { type: 'boolean', label: 'Force Recompute', default: false },
+    },
 };
 
+/** Overwrite `fileName` even when another writer already set one. Default off. */
+let forceRecompute = false;
+
+export function configure(config: Record<string, unknown>): void {
+    forceRecompute = config.forceRecompute === true;
+    console.log(`[file-info] Config: forceRecompute=${forceRecompute}`);
+}
+
+/**
+ * Whether we may write `fileName` on this record.
+ *
+ * `fileName` has **two writers** (METADATA_KEYS.md §`fileName`): this plugin,
+ * which knows the on-disk basename, and the indexer feeders, which emit the raw
+ * release string at ingest. They meet on one record whenever meta-share
+ * materialises a search hit into a tree meta-core watches — the bytes' midhash
+ * is the record's content CID, so this plugin lands on the record the feeder
+ * already wrote.
+ *
+ * A Usenet posting's on-disk name is the poster's, and posters obfuscate it
+ * (`9765de45fa2d4522a80d01363d3c0919.mkv`). Writing it unconditionally destroyed
+ * the only readable name the record had, in a last-writer-wins race that showed
+ * up as hex on meta-watch's source rows.
+ *
+ * Precedence, mirroring the `still` rule the registry already legislates: the
+ * writer that knows less yields, and it yields by skipping a record that already
+ * carries a value. We know less — a basename is a container's filing detail,
+ * a release string is the release's identity.
+ *
+ * The record is re-read over the network rather than trusted from
+ * `existingMeta`: that map is delivered nested for grouped keys, and it is
+ * snapshotted before dispatch. `existingMeta` is the fallback for standalone /
+ * test mode, where `getProperty` cannot reach meta-core and answers `null`.
+ */
+async function mayWriteFileName(
+    metaCore: MetaCoreClient,
+    request: ProcessRequest,
+    cid: string,
+    fileName: string
+): Promise<boolean> {
+    if (forceRecompute) return true;
+    const existing = (await metaCore.getProperty(cid, 'fileName')) ?? request.existingMeta?.fileName ?? null;
+    if (!existing || existing === fileName) return true;
+    console.log(`[file-info] Keeping existing fileName "${existing}" (not overwriting with "${fileName}")`);
+    return false;
+}
+
 export async function process(
     request: ProcessRequest,
     sendCallback: (payload: CallbackPayload) => Promise<void>
@@ -165,7 +213,12 @@ export async function process(
             await metaCore.setProperty(cid, 'mimeType', mimeType);
         }
         await metaCore.setProperty(cid, 'sizeByte', String(fileSize));
-        await metaCore.setProperty(cid, 'fileName', fileName);
+        if (await mayWriteFileName(metaCore, request, cid, fileName)) {
+            await metaCore.setProperty(cid, 'fileName', fileName);
+        }
+        // `extension` is unguarded on purpose: METADATA_KEYS.md names exactly one
+        // writer for it (this plugin), so there is nothing to yield to — and it
+        // describes the bytes on disk, which is precisely what we are looking at.
         await metaCore.setProperty(cid, 'extension', extension);
 
         const duration = Date.now() - startTime;

test/filename-guard.test.ts

@@ -0,0 +1,179 @@
+/**
+ * `fileName` precedence regression tests.
+ *
+ * `fileName` has two writers (METADATA_KEYS.md §`fileName`): this plugin, which
+ * knows a file's on-disk basename, and the indexer feeders, which emit the raw
+ * release string at ingest. They collide on one record whenever meta-share
+ * materialises a search hit into a tree meta-core watches.
+ *
+ * The regression these guard: a Usenet posting's on-disk name is the poster's,
+ * and posters obfuscate it — writing it unconditionally replaced the readable
+ * release string with `9765de45fa2d4522a80d01363d3c0919.mkv` on a record the
+ * whole UI reads.
+ *
+ * These drive the real write path against a stand-in meta-core, so they assert
+ * what is actually PUT rather than what the callback says.
+ */
+
+import { describe, it, expect, beforeAll, afterAll, beforeEach } from 'vitest';
+import * as http from 'http';
+import { promises as fs } from 'fs';
+import * as path from 'path';
+import * as os from 'os';
+
+let processFile: typeof import('../src/plugin.js').process;
+let configure: typeof import('../src/plugin.js').configure;
+
+/** Properties the stand-in meta-core currently holds, per cid. */
+let record: Record<string, string>;
+/** Every `PUT /meta/{cid}/{key}` the plugin made, in order. */
+let writes: Array<{ key: string; value: string }>;
+
+let server: http.Server;
+let metaCoreUrl: string;
+let testDir: string;
+/** A file whose basename is the obfuscated shape a Usenet poster produces. */
+let obfuscatedFile: string;
+
+const OBFUSCATED = '9765de45fa2d4522a80d01363d3c0919.mkv';
+const RELEASE = 'The.Magical.Revolution.of.the.Reincarnated.Princess-S01E09';
+
+const noopCallback = async (): Promise<void> => {};
+
+/** Run the plugin over the obfuscated-named file against the stand-in meta-core. */
+async function run(cid: string, existingMeta: Record<string, string> = {}): Promise<void> {
+    await processFile(
+        {
+            taskId: `task-${cid}`,
+            cid,
+            filePath: obfuscatedFile,
+            callbackUrl: 'http://localhost/callback',
+            metaCoreUrl,
+            existingMeta,
+        },
+        noopCallback
+    );
+}
+
+const written = (key: string): string | undefined => writes.find((w) => w.key === key)?.value;
+
+beforeAll(async () => {
+    const plugin = await import('../src/plugin.js');
+    processFile = plugin.process;
+    configure = plugin.configure;
+
+    testDir = await fs.mkdtemp(path.join(os.tmpdir(), 'file-info-guard-'));
+    obfuscatedFile = path.join(testDir, OBFUSCATED);
+    await fs.writeFile(obfuscatedFile, 'fake video content');
+
+    // Stand-in meta-core: just enough of the property API for this plugin.
+    server = http.createServer((req, res) => {
+        const url = new URL(req.url ?? '/', 'http://localhost');
+        const parts = url.pathname.split('/').filter(Boolean); // ['meta', cid, key?]
+        const key = parts[2];
+        if (req.method === 'GET' && key) {
+            const value = record[key];
+            if (value === undefined) {
+                res.writeHead(404).end();
+                return;
+            }
+            res.writeHead(200, { 'Content-Type': 'application/json' }).end(JSON.stringify({ value }));
+            return;
+        }
+        if (req.method === 'PUT' && key) {
+            let body = '';
+            req.on('data', (c) => (body += c));
+            req.on('end', () => {
+                const value = String(JSON.parse(body || '{}').value ?? '');
+                writes.push({ key, value });
+                record[key] = value;
+                res.writeHead(200, { 'Content-Type': 'application/json' }).end('{}');
+            });
+            return;
+        }
+        res.writeHead(200, { 'Content-Type': 'application/json' }).end('{}');
+    });
+    await new Promise<void>((resolve) => server.listen(0, '127.0.0.1', resolve));
+    const addr = server.address() as { port: number };
+    metaCoreUrl = `http://127.0.0.1:${addr.port}`;
+});
+
+afterAll(async () => {
+    await new Promise<void>((resolve) => server.close(() => resolve()));
+    await fs.rm(testDir, { recursive: true, force: true });
+});
+
+beforeEach(() => {
+    record = {};
+    writes = [];
+    configure({}); // forceRecompute defaults back to off
+});
+
+describe('fileName precedence', () => {
+    it('never overwrites a release string a feeder already wrote', async () => {
+        record.fileName = RELEASE;
+
+        await run('cid-feeder-wrote-first');
+
+        expect(written('fileName')).toBeUndefined();
+        expect(record.fileName).toBe(RELEASE);
+    });
+
+    it('still writes every key it owns when it yields on fileName', async () => {
+        record.fileName = RELEASE;
+
+        await run('cid-other-keys-survive');
+
+        // `extension` has exactly one writer, so it is never withheld — and it
+        // describes the bytes on disk, which is what this plugin is looking at.
+        expect(written('extension')).toBe('mkv');
+        expect(written('sizeByte')).toBe('18');
+        expect(written('fileType')).toBeDefined();
+    });
+
+    it('writes fileName when the record carries none', async () => {
+        await run('cid-first-sighting');
+
+        expect(written('fileName')).toBe(OBFUSCATED);
+    });
+
+    it('writes fileName when the record already holds the same value', async () => {
+        record.fileName = OBFUSCATED;
+
+        await run('cid-same-value');
+
+        expect(record.fileName).toBe(OBFUSCATED);
+    });
+
+    it('overwrites when forceRecompute is on', async () => {
+        record.fileName = RELEASE;
+        configure({ forceRecompute: true });
+
+        await run('cid-forced');
+
+        expect(written('fileName')).toBe(OBFUSCATED);
+    });
+
+    /**
+     * Standalone / test mode: `getProperty` cannot reach meta-core and answers
+     * `null` for both "absent" and "unreachable", so the dispatch snapshot is
+     * the only evidence left that someone else owns the key.
+     */
+    it('falls back to existingMeta when meta-core is unreachable', async () => {
+        const unreachable = 'http://127.0.0.1:1';
+        await processFile(
+            {
+                taskId: 'task-offline',
+                cid: 'cid-offline',
+                filePath: obfuscatedFile,
+                callbackUrl: 'http://localhost/callback',
+                metaCoreUrl: unreachable,
+                existingMeta: { fileName: RELEASE },
+            },
+            noopCallback
+        );
+
+        // Nothing reached our stand-in meta-core, and nothing threw.
+        expect(writes).toHaveLength(0);
+    });
+});