[torcolvin]

Stacked on #99.

Makes rosmar match Couchbase Server for tombstones, expiry and nil writes. Each behavior has a sync_gateway test with the same name and cases. That test passes on Couchbase Server 8.0.1 and on this branch.

What changes

• Deletes and tombstone writes: a tombstone counts as missing for Delete, Remove and DeleteSubDocPaths. DeleteWithXattrs removes user xattrs. A CAS of 0 means no CAS check.
• CAS writes: a non-zero CAS on a tombstone returns not found, and a CAS of 0 resurrects it. SetXattrs creates a missing document, and UpdateXattrs requires an existing one.
• Expiry: every delete leaves a tombstone with no expiry. A write over a tombstone with PreserveExpiry has no expiry. WriteUpdateWithXattrs now uses its exp argument, which a local variable hid.
• Nil values: WriteCas never creates a tombstone. An untyped nil writes null, and a nil []byte writes an empty body. Update inserts over a missing key or a tombstone, even for a delete, as the gocb version in sync_gateway does.

Testing

• go test -race ./... and golangci-lint pass.
• sync_gateway base passes against this branch on rosmar. auth, db and rest pass against the same changes with Serialize OpenBucket and stop expiration before closing the bucket #100 applied.
• The matching sync_gateway tests pass on Couchbase Server 8.0.1.

🤖 Generated with Claude Code

[Copilot]

Copilot review overview

🟡 Changes recommended

Three unresolved findings remain, including one critical error-handling issue.

Review effort: Lite
Findings: 1

Open (1)

• Propagate nested xattr deletion path errors · New

What changed in this PR

Aligns rosmar with Couchbase Server semantics for tombstones, expiry, CAS, xattrs, subdocuments, and nil writes.

Changes:

• Updates deletion, resurrection, CAS, expiry, and nil-write behavior.
• Adjusts xattr and subdocument handling.
• Expands regression and compatibility test coverage.

File	Reviewed changes	Findings
xattrs_test.go	Adds xattr, tombstone, and update coverage.	None
collection+xattrs.go	Updates xattr operations, expiry, tombstone handling, and virtual metadata.	Critical error propagation issue in DeleteWithXattrs; moderate missing $document.deleted subpath support.
collection+subdoc.go	Handles subdocument writes over tombstones.	None
collection.go	Adjusts CAS, deletion, resurrection, nil writes, and update behavior.	Moderate MissingError retry issue in Update.
collection_test.go	Adds broad behavior and expiry coverage.	None
bucket_test.go	Extends expiration tests.	None

---

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[bbrks]

repro test covering nil/empty byte slices (run same test cases against cb server to compare behaviour - test as-suggested should match cb server/gocb)

one edge case around xattr-only write

[bbrks]

Suggested change

	// TestNilWritesStoreBody checks that Set, SetRaw, Add, AddRaw and WriteWithXattrs with a nil value write
	// a live document, as Couchbase Server does: an untyped nil writes a null JSON body and a nil []byte writes an empty body.
	func TestNilWritesStoreBody(t *testing.T) {
	ctx := t.Context()
	dataStore := makeTestBucket(t).DefaultDataStore(ctx).(*Collection)
	testCases := []struct {
	name string
	live bool // write over a live doc with a system and a user xattr
	write func(t *testing.T, key string)
	expectedBody string
	}{
	{
	name: "Set",
	write: func(t *testing.T, key string) { require.NoError(t, dataStore.Set(ctx, key, 0, nil, nil)) },
	expectedBody: "null",
	},
	{
	name: "SetOverLive",
	live: true,
	write: func(t *testing.T, key string) { require.NoError(t, dataStore.Set(ctx, key, 0, nil, nil)) },
	expectedBody: "null",
	},
	{
	name: "SetRaw",
	write: func(t *testing.T, key string) { require.NoError(t, dataStore.SetRaw(ctx, key, 0, nil, nil)) },
	},
	{
	name: "Add",
	write: func(t *testing.T, key string) {
	added, err := dataStore.Add(ctx, key, 0, nil)
	require.NoError(t, err)
	require.True(t, added)
	},
	expectedBody: "null",
	},
	{
	name: "AddRaw",
	write: func(t *testing.T, key string) {
	added, err := dataStore.AddRaw(ctx, key, 0, nil)
	require.NoError(t, err)
	require.True(t, added)
	},
	},
	{
	name: "WriteWithXattrsNilBody",
	write: func(t *testing.T, key string) {
	_, err := dataStore.WriteWithXattrs(ctx, key, 0, 0, nil, map[string][]byte{"_sync": []byte(`{"rev":"1-a"}`)}, nil, nil)
	require.NoError(t, err)
	},
	expectedBody: "null",
	},
	}
	for _, tc := range testCases {
	t.Run(tc.name, func(t *testing.T) {
	key := t.Name()
	if tc.live {
	_, err := dataStore.WriteWithXattrs(ctx, key, 0, 0, []byte(`{"foo":"bar"}`),
	map[string][]byte{"_sync": []byte(`{"rev":"1-a"}`), "user": []byte(`{"u":1}`)}, nil, nil)
	require.NoError(t, err)
	}
	tc.write(t, key)
	assert.False(t, getDocRow(t, dataStore, key).tombstone, "nil write created a tombstone")
	body, _, err := dataStore.GetRaw(ctx, key)
	require.NoError(t, err)
	require.Equal(t, tc.expectedBody, string(body))
	if tc.live {
	xattrs, _, err := dataStore.GetXattrs(ctx, key, []string{"_sync", "user"})
	require.NoError(t, err)
	require.JSONEq(t, `{"rev":"1-a"}`, string(xattrs["_sync"]))
	require.JSONEq(t, `{"u":1}`, string(xattrs["user"]))
	}
	})
	}
	}

[torcolvin]

Added unchanged in f8e7228. Set/Add with nil now store null, and SetRaw/AddRaw store an empty body. Before, rosmar stored a NULL value, which Get read as missing.