From 8dabbba09216d066e82c486a6d8640c8c6ca114e Mon Sep 17 00:00:00 2001
From: Chris Peyer <chrischrischris@users.noreply.github.com>
Date: Wed, 13 May 2026 10:41:19 -0400
Subject: [PATCH] fix: coerce non-string da-metadata values to avoid "[object
 Object]"

setDaMetadata is the single boundary into the daMetadata Y.Map, but it
forwarded values verbatim. doc2aem later interpolates each value into a
<div>${value}</div>, so any non-string entry (object, Y type) ended up
serialized as the literal string "[object Object]" in saved HTML.

Coerce at the boundary: stringify objects via JSON.stringify, other
non-strings via String(), and warn so the offending caller surfaces.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
---
 blocks/edit/utils/helpers.js                | 13 +++++++++--
 test/unit/blocks/edit/utils/helpers.test.js | 25 +++++++++++++++++++++
 2 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/blocks/edit/utils/helpers.js b/blocks/edit/utils/helpers.js
index 51a0494be..dc34d7e25 100644
--- a/blocks/edit/utils/helpers.js
+++ b/blocks/edit/utils/helpers.js
@@ -345,9 +345,18 @@ export function setDaMetadata(key, value) {
   if (!daMdMap) return;
   if (value === null || value === undefined) {
     daMdMap.delete(key);
-  } else {
-    daMdMap.set(key, value);
+    return;
+  }
+  // The Y.Map serializes to a <div class="da-metadata"> block where values are
+  // interpolated as text. Non-strings (objects, Y types) would render as
+  // "[object Object]" in the saved HTML, so coerce at the boundary.
+  let stringValue = value;
+  if (typeof stringValue !== 'string') {
+    // eslint-disable-next-line no-console
+    console.warn(`setDaMetadata: non-string value for "${key}"`, value);
+    stringValue = typeof value === 'object' ? JSON.stringify(value) : String(value);
   }
+  daMdMap.set(key, stringValue);
 }
 
 export function getDiffLabels() {
diff --git a/test/unit/blocks/edit/utils/helpers.test.js b/test/unit/blocks/edit/utils/helpers.test.js
index 7d0642554..49520d8d9 100644
--- a/test/unit/blocks/edit/utils/helpers.test.js
+++ b/test/unit/blocks/edit/utils/helpers.test.js
@@ -621,6 +621,31 @@ describe('daMetadata functions', () => {
       expect(getDaMetadata('key2')).to.be.null;
       expect(getDaMetadata('key3')).to.equal('value3');
     });
+
+    it('Coerces object values to JSON strings to avoid "[object Object]"', () => {
+      const originalWarn = console.warn;
+      console.warn = () => {};
+      try {
+        setDaMetadata('obj-key', { a: 1, b: 'two' });
+        expect(getDaMetadata('obj-key')).to.equal('{"a":1,"b":"two"}');
+      } finally {
+        console.warn = originalWarn;
+      }
+    });
+
+    it('Coerces non-string primitive values to strings', () => {
+      const originalWarn = console.warn;
+      console.warn = () => {};
+      try {
+        setDaMetadata('num-key', 42);
+        expect(getDaMetadata('num-key')).to.equal('42');
+
+        setDaMetadata('bool-key', true);
+        expect(getDaMetadata('bool-key')).to.equal('true');
+      } finally {
+        console.warn = originalWarn;
+      }
+    });
   });
 });