fix(core): pass object bindings in __setLogger child() call (#15079)

Co-authored-by: Mastra Code (anthropic/claude-opus-4-6) <noreply@mastra.ai>

Author: roaminro

.changeset/perky-mammals-wink.md

@@ -0,0 +1,5 @@
+---
+'@mastra/core': patch
+---
+
+Fixed `__setLogger` passing a raw string to `logger.child()`, which caused PinoLogger to serialize each character as a separate log field (e.g. `0: "B", 1: "U", 2: "N"...`). Now passes `{ component }` object instead.

packages/core/src/base.ts

@@ -45,7 +45,9 @@ export class MastraBase {
    */
   __setLogger(logger: IMastraLogger) {
     this.logger =
-      'child' in logger && typeof (logger as any).child === 'function' ? (logger as any).child(this.component) : logger;
+      'child' in logger && typeof (logger as any).child === 'function'
+        ? (logger as any).child({ component: this.component })
+        : logger;
   }
 }
 

packages/core/src/logger/default-logger.ts

@@ -41,7 +41,11 @@ export class ConsoleLogger extends MastraLogger {
     this.filter = options.filter;
   }
 
-  child(component: RegisteredLogger): ConsoleLogger {
+  child(componentOrBindings: RegisteredLogger | Record<string, unknown>): ConsoleLogger {
+    const component =
+      typeof componentOrBindings === 'string'
+        ? componentOrBindings
+        : ((componentOrBindings?.component as RegisteredLogger) ?? this.component);
     return new ConsoleLogger({
       name: this.name,
       level: this.level,