fix(shared): use truncateUtf16Safe in assistant-identity-values

Simon-XYDT · Simon-XYDT · commit 9e7972095d03 · 2026-07-10T01:35:01.000+08:00
Replace raw .slice(0, maxLength) with truncateUtf16Safe to prevent emoji surrogate pair truncation issues in assistant identity values. The coerceIdentityValue function is used to truncate assistant name, avatar, and emoji values. When these values contain emoji at the truncation boundary, the old implementation could produce lone surrogates (invalid UTF-16 text). This fix follows the same pattern as PR #102477 which addressed similar issues in talk/fast-context-runtime.ts and infra/heartbeat-events-filter.ts.
diff --git a/src/shared/assistant-identity-values.test.ts b/src/shared/assistant-identity-values.test.ts
@@ -20,6 +20,26 @@ describe("shared/assistant-identity-values", () => {
 
   it("returns an empty string when truncating to a zero-length limit", () => {
     expect(coerceIdentityValue("  OpenClaw  ", 0)).toBe("");
-    expect(coerceIdentityValue("  OpenClaw  ", -1)).toBe("OpenCla");
+    // truncateUtf16Safe returns empty string for negative limits
+    expect(coerceIdentityValue("  OpenClaw  ", -1)).toBe("");
+  });
+
+  it("handles emoji surrogate pairs safely at truncation boundary", () => {
+    // Emoji at the truncation boundary should not produce lone surrogates
+    // 🚀 is a surrogate pair (2 UTF-16 code units)
+    const textWithEmoji = "x".repeat(9) + "🚀" + "yz"; // emoji at position 10-11 (UTF-16 indices)
+
+    // truncateUtf16Safe safely handles emoji boundaries:
+    // - At limit 10: drops the emoji (would be lone surrogate)
+    // - At limit 11: includes the full emoji (both surrogates fit)
+    expect(coerceIdentityValue(textWithEmoji, 10)).toBe("xxxxxxxxx");
+    expect(coerceIdentityValue(textWithEmoji, 11)).toBe("xxxxxxxxx🚀");
+    expect(coerceIdentityValue(textWithEmoji, 12)).toBe("xxxxxxxxx🚀y");
+
+    // Verify no lone surrogates in any result
+    for (const limit of [5, 10, 11, 12, 15]) {
+      const result = coerceIdentityValue(textWithEmoji, limit)!;
+      expect([...result].every((c) => !(c >= "\uDC00" && c <= "\uDFFF"))).toBe(true);
+    }
   });
 });
diff --git a/src/shared/assistant-identity-values.ts b/src/shared/assistant-identity-values.ts
@@ -1,5 +1,6 @@
-// Assistant identity helpers normalize assistant identity labels and metadata.
 import { normalizeOptionalString } from "@openclaw/normalization-core/string-coerce";
+// Assistant identity helpers normalize assistant identity labels and metadata.
+import { truncateUtf16Safe } from "@openclaw/normalization-core/utf16-slice";
 
 /** Normalizes optional assistant identity fields and truncates them to the caller's limit. */
 export function coerceIdentityValue(
@@ -13,5 +14,5 @@ export function coerceIdentityValue(
   if (trimmed.length <= maxLength) {
     return trimmed;
   }
-  return trimmed.slice(0, maxLength);
+  return truncateUtf16Safe(trimmed, maxLength);
 }

Original file line number	Diff line number	Diff line change
`@@ -1,5 +1,6 @@`
`1`		`-// Assistant identity helpers normalize assistant identity labels and metadata.`
`2`	`1`	`import { normalizeOptionalString } from "@openclaw/normalization-core/string-coerce";`
	`2`	`+// Assistant identity helpers normalize assistant identity labels and metadata.`
	`3`	`+import { truncateUtf16Safe } from "@openclaw/normalization-core/utf16-slice";`
`3`	`4`
`4`	`5`	`/** Normalizes optional assistant identity fields and truncates them to the caller's limit. */`
`5`	`6`	`export function coerceIdentityValue(`
`@@ -13,5 +14,5 @@ export function coerceIdentityValue(`
`13`	`14`	`if (trimmed.length <= maxLength) {`
`14`	`15`	`return trimmed;`
`15`	`16`	`}`
`16`		`- return trimmed.slice(0, maxLength);`
	`17`	`+ return truncateUtf16Safe(trimmed, maxLength);`
`17`	`18`	`}`