getContent() returns empty Buffer instead of throwing/null for missing blob OID

[flyingrobots]

Summary

graph.getContent(nodeId) returns Buffer.alloc(0) when the blob OID referenced by CONTENT_PROPERTY_KEY doesn't exist in the git object store. The type signature (Promise<Buffer | null>) and docs suggest it should return null or throw.

Expected behavior

One of:

• Return null (consistent with the type signature)
• Throw an Error (consistent with the JSDoc: "Throws generic Error if referenced blob OID not in object store")

Actual behavior

Returns an empty Buffer (length 0), which is truthy and passes null checks silently.

Reproduction

const patch = await graph.createPatch();
patch.addNode('test:node');
await patch.attachContent('test:node', Buffer.from('hello'));
await patch.commit();

// Corrupt the content OID to point at a non-existent blob
const patch2 = await graph.createPatch();
patch2.setProperty('test:node', CONTENT_PROPERTY_KEY, 'deadbeefdeadbeefdeadbeefdeadbeefdeadbeef');
await patch2.commit();

const buf = await graph.getContent('test:node');
// Expected: null or thrown error
// Actual: Buffer.alloc(0) — empty buffer, truthy, no error

Impact

Consumers relying on the null check or try/catch to detect missing blobs will silently get empty content. We worked around this in git-mind with a size-mismatch guard (contentBuf.length === 0 && meta.size > 0), but the API contract should handle this at the WARP layer.

Version

git-warp v11.5.0