From 904edb391d0bbd8510c01927a21c1b6ca159aa7e Mon Sep 17 00:00:00 2001
From: Nick Bernal <nick@superdoc.dev>
Date: Thu, 29 Jan 2026 22:21:48 -0800
Subject: [PATCH] fix: run color overwrite in applyInlineRunProperties
 (SD-1585)

---
 .../inline-converters/common.test.ts          | 82 +++++++++++++++++++
 .../converters/inline-converters/common.ts    |  8 +-
 2 files changed, 89 insertions(+), 1 deletion(-)
 create mode 100644 packages/layout-engine/pm-adapter/src/converters/inline-converters/common.test.ts

diff --git a/packages/layout-engine/pm-adapter/src/converters/inline-converters/common.test.ts b/packages/layout-engine/pm-adapter/src/converters/inline-converters/common.test.ts
new file mode 100644
index 0000000000..9683832940
--- /dev/null
+++ b/packages/layout-engine/pm-adapter/src/converters/inline-converters/common.test.ts
@@ -0,0 +1,82 @@
+import { describe, it, expect, vi } from 'vitest';
+import type { TextRun } from '@superdoc/contracts';
+import type { RunProperties } from '@superdoc/style-engine/ooxml';
+import { applyInlineRunProperties } from './common.js';
+
+vi.mock('../../attributes/paragraph.js', () => ({
+  computeRunAttrs: vi.fn((runProps: RunProperties) => ({
+    fontFamily: 'Arial',
+    fontSize: 12,
+    bold: runProps.bold,
+    italic: runProps.italic,
+    color: runProps.color?.val ? `#${runProps.color.val.toUpperCase()}` : undefined,
+  })),
+}));
+
+describe('applyInlineRunProperties', () => {
+  const baseRun: TextRun = {
+    text: 'Hello',
+    fontFamily: 'Times New Roman',
+    fontSize: 16,
+  };
+
+  it('returns unchanged run when runProperties is undefined', () => {
+    const result = applyInlineRunProperties(baseRun, undefined);
+
+    expect(result).toBe(baseRun);
+  });
+
+  it('merges computed attributes from runProperties onto the run', () => {
+    const runProperties: RunProperties = { bold: true };
+
+    const result = applyInlineRunProperties(baseRun, runProperties);
+
+    expect(result.bold).toBe(true);
+    expect(result.fontFamily).toBe('Arial');
+    expect(result.fontSize).toBe(12);
+    expect(result.text).toBe('Hello');
+  });
+
+  it('preserves run.color when runProperties does not specify a color', () => {
+    const runWithColor: TextRun = {
+      ...baseRun,
+      color: '#FF0000',
+    };
+    const runProperties: RunProperties = { bold: true };
+
+    const result = applyInlineRunProperties(runWithColor, runProperties);
+
+    expect(result.color).toBe('#FF0000');
+  });
+
+  it('overwrites run.color when runProperties specifies a color', () => {
+    const runWithColor: TextRun = {
+      ...baseRun,
+      color: '#FF0000',
+    };
+    const runProperties: RunProperties = {
+      color: { val: '00FF00' },
+    };
+
+    const result = applyInlineRunProperties(runWithColor, runProperties);
+
+    expect(result.color).toBe('#00FF00');
+  });
+
+  it('does not set color when both run and runProperties have no color', () => {
+    const runProperties: RunProperties = { bold: true };
+
+    const result = applyInlineRunProperties(baseRun, runProperties);
+
+    expect(result.color).toBeUndefined();
+  });
+
+  it('returns a new object instead of mutating the original run', () => {
+    const runProperties: RunProperties = { italic: true };
+
+    const result = applyInlineRunProperties(baseRun, runProperties);
+
+    expect(result).not.toBe(baseRun);
+    expect(baseRun.italic).toBeUndefined();
+  });
+});
diff --git a/packages/layout-engine/pm-adapter/src/converters/inline-converters/common.ts b/packages/layout-engine/pm-adapter/src/converters/inline-converters/common.ts
index f602838eff..87864791b5 100644
--- a/packages/layout-engine/pm-adapter/src/converters/inline-converters/common.ts
+++ b/packages/layout-engine/pm-adapter/src/converters/inline-converters/common.ts
@@ -80,5 +80,11 @@ export const applyInlineRunProperties = (
     return run;
   }
   const runAttrs = computeRunAttrs(runProperties, converterContext);
-  return { ...run, ...runAttrs };
+  const merged = { ...run, ...runAttrs };
+  // Preserve existing run color when runProperties doesn't specify one.
+  // Object spread with undefined values overwrites the original, so we restore it.
+  if (runAttrs.color === undefined && run.color !== undefined) {
+    merged.color = run.color;
+  }
+  return merged;
 };