fix(managed): report stream-name errors at file offsets (#4418)

Co-authored-by: Mark <m-user@Marks-MacBook-Air.local>

src/dotnet/ManagedMetadataLayout.ts

@@ -141,8 +141,10 @@ const requireRange = (
 
 const align4 = (value: number): number => Math.ceil(value / 4) * 4;
 
+/** Read within the metadata root; report failures at artifact file offsets. */
 const readStreamName = (
   bytes: Buffer,
+  rootOffset: number,
   offset: number,
 ): { readonly name: string; readonly next: number } => {
   const endLimit = Math.min(bytes.length, offset + 32);
@@ -153,7 +155,7 @@ const readStreamName = (
       "invalid-stream",
       "metadata.stream-name",
       "Metadata stream name is missing a bounded terminator",
-      offset,
+      rootOffset + offset,
     );
   const nameBytes = bytes.subarray(offset, end);
   if (nameBytes.some((byte) => byte < 0x20 || byte > 0x7e))
@@ -161,7 +163,7 @@ const readStreamName = (
       "invalid-stream",
       "metadata.stream-name",
       "Metadata stream name is not printable ASCII",
-      offset,
+      rootOffset + offset,
     );
   return {
     name: nameBytes.toString("ascii"),
@@ -250,7 +252,7 @@ const readMetadataStreams = (
     requireRange(bytes, rootOffset, cursor, 8, "metadata.stream-header");
     const relativeOffset = bytes.readUInt32LE(cursor);
     const streamSize = bytes.readUInt32LE(cursor + 4);
-    const named = readStreamName(bytes, cursor + 8);
+    const named = readStreamName(bytes, rootOffset, cursor + 8);
     if (streams.has(named.name))
       throw managedFailure(
         "invalid-stream",