From 6ae4e3028482f575adec82e252a304dba4b7cd9d Mon Sep 17 00:00:00 2001
From: David <david@Davids-MacBook-Neo.local>
Date: Tue, 6 Oct 2026 10:49:10 +0200
Subject: [PATCH] Invoices: ship pdfjs-dist's worker into the standalone image
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Every PDF import failed in production with "Setting up fake worker failed:
Cannot find module '/app/node_modules/pdfjs-dist/legacy/build/pdf.worker.mjs'".

output: "standalone" ships only the files Next's output tracer can see. It
traced pdf.mjs, because lib/invoice-parser.ts imports it by literal path,
but the worker's sole reference is a createRequire(...).resolve() call,
which the tracer does not follow. So the image contained pdf.mjs alone,
pdfjs fell back to its default "./pdf.worker.mjs" relative to pdf.mjs, and
the import hit a file that was never copied.

Copy the whole package in the runner stage: the worker has to sit next to
pdf.mjs, and so do the standard fonts, which the parser needs because it
passes useSystemFonts. Verified against the reconstructed runner layout —
the old layout reproduces the error verbatim, the new one parses and
extracts text.

Also in lib/invoice-parser.ts: workerPinned was set before the resolve, so
a failed resolve was never retried; and the empty catch swallowed the
MODULE_NOT_FOUND that named the real cause. Both fixed.
---
 Dockerfile            |  9 +++++++++
 lib/invoice-parser.ts | 19 ++++++++++++++-----
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/Dockerfile b/Dockerfile
index 5074a7e..f85c2b2 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -78,6 +78,15 @@ COPY --from=builder /app/public ./public
 COPY --from=builder --chown=nextjs:nodejs /app/.next/standalone ./
 COPY --from=builder --chown=nextjs:nodejs /app/.next/static ./.next/static
 
+# Next's output tracer cannot see pdfjs-dist's worker. The only reference to it
+# is a createRequire(...).resolve() call, which the tracer does not follow, so
+# the standalone bundle ships pdf.mjs WITHOUT pdf.worker.mjs — and every parse
+# then dies with "Setting up fake worker failed: Cannot find module
+# '/app/node_modules/pdfjs-dist/legacy/build/pdf.worker.mjs'". Copy the package
+# in whole: the worker has to sit next to pdf.mjs at runtime, and so do the
+# standard fonts, which the parser needs because it passes useSystemFonts.
+COPY --from=deps --chown=nextjs:nodejs /app/node_modules/pdfjs-dist ./node_modules/pdfjs-dist
+
 USER nextjs
 EXPOSE 3000
 
diff --git a/lib/invoice-parser.ts b/lib/invoice-parser.ts
index 1a8319a..88d4647 100644
--- a/lib/invoice-parser.ts
+++ b/lib/invoice-parser.ts
@@ -172,21 +172,30 @@ export function isoDate(s: string): string {
 // falls back to a dynamic import of the worker module, which the bundler rewrites to a
 // .next path that does not exist in the standalone image — every parse then dies with
 // "Setting up fake worker failed". Pinning the worker to the real installed file avoids
-// that. pdfjs-dist is listed in serverExternalPackages so it is required (and traced)
-// from node_modules rather than bundled.
+// that, but only if the file is actually there: pdfjs-dist is in
+// serverExternalPackages so it is required from node_modules rather than bundled, and
+// Next's tracer does NOT copy pdf.worker.mjs — the standalone bundle contains pdf.mjs
+// alone. The Dockerfile copies the whole package in for that reason. Do not assume this
+// pin alone is sufficient.
 let workerPinned = false;
 async function loadPdfjs() {
   const pdfjs = await import("pdfjs-dist/legacy/build/pdf.mjs");
   if (!workerPinned) {
-    workerPinned = true;
     try {
       const { createRequire } = await import("node:module");
       const req = createRequire(import.meta.url);
       pdfjs.GlobalWorkerOptions.workerSrc = req.resolve(
         "pdfjs-dist/legacy/build/pdf.worker.mjs",
       );
-    } catch {
-      // Leave pdfjs's own default in place; it is correct for unbundled Node.
+      workerPinned = true;
+    } catch (err) {
+      // Not fatal, but it must not be silent: pdfjs then falls back to a worker
+      // path relative to pdf.mjs, so the parse fails much later with an opaque
+      // "Setting up fake worker failed". Staying UNpinned lets the next parse
+      // retry, so the worker is picked up as soon as it is on disk.
+      console.error(
+        `[invoice-parser] could not resolve pdf.worker.mjs: ${(err as Error).message}`,
+      );
     }
   }
   return pdfjs;