spanner: examine test results for RequestIDHeader when environment variable GOOGLE_CLOUD_SPANNER_MULTIPLEXED_SESSIONS=true

[odeke-em]

Reported to me offline by @rahul2393 and I ran tests to find failures due to the oddities which happen with multiplexed sessions and also seeming inconsistencies like only being enabled for ReadOnlyTransactions and pure WriteTransactions on main

$ GOOGLE_CLOUD_SPANNER_MULTIPLEXED_SESSIONS=true go test -short -run=.
2024/12/18 05:24:42 Integration tests skipped in -short mode.
--- FAIL: TestRequestIDHeader_onRetriesWithFailedTransactionCommit (0.01s)
    request_id_header_test.go:494: unaryClientCall is incorrect; got=6 want=5
--- FAIL: TestRequestIDHeader_SingleUseReadOnly_ExecuteStreamingSql_Unavailable (0.02s)
    request_id_header_test.go:1512: unaryClientCall is incorrect; got=2 want=1
    request_id_header_test.go:1536: RequestID unary segments mismatch: got - want +
          []*spanner.requestIDSegments{
          	&{
          		... // 2 identical fields
          		ClientID:  54,
          		RequestNo: 1,
        - 		ChannelID: 2,
        + 		ChannelID: 1,
          		RPCNo:     1,
          	},
        - 	s"1.10766896037511722208.54.1.2.1",
          }
--- FAIL: TestRequestIDHeader_SingleUseReadOnly_ExecuteStreamingSql_UnavailableDuringStream (0.05s)
    request_id_header_test.go:1842: unaryClientCall is incorrect; got=2 want=1
    request_id_header_test.go:1862: RequestID unary segments mismatch: got - want +
          []*spanner.requestIDSegments{
          	&{
          		... // 2 identical fields
          		ClientID:  49,
          		RequestNo: 1,
        - 		ChannelID: 2,
        + 		ChannelID: 1,
          		RPCNo:     1,
          	},
        - 	s"1.10766896037511722208.49.1.2.1",
          }
--- FAIL: TestRequestIDHeader_BatchCreateSessions_Unavailable (0.01s)
    request_id_header_test.go:1426: got 3 requests, want 4 requests:
        got:
        *spannerpb.CreateSessionRequest: database:"projects/[PROJECT]/instances/[INSTANCE]/databases/[DATABASE]"  session:{multiplexed:true}]
        *spannerpb.BatchCreateSessionsRequest: database:"projects/[PROJECT]/instances/[INSTANCE]/databases/[DATABASE]"  session_template:{}  session_count:2]
        *spannerpb.ExecuteSqlRequest: session:"projects/[PROJECT]/instances/[INSTANCE]/databases/[DATABASE]/sessions/multiplexed-3"  transaction:{single_use:{read_only:{strong:true  return_read_timestamp:true}}}  sql:"SELECT FOO FROM BAR"  params:{}  seqno:1  query_options:{}  request_options:{}]
        
        want:
        *spannerpb.CreateSessionRequest: ]
        *spannerpb.BatchCreateSessionsRequest: ]
        *spannerpb.BatchCreateSessionsRequest: ]
        *spannerpb.ExecuteSqlRequest: ]
        
--- FAIL: TestRequestIDHeader_ReadWriteTransactionUpdate (0.01s)
    request_id_header_test.go:1098: unaryClientCall is incorrect; got=7 want=6
--- FAIL: TestRequestIDHeader_ReadWriteTransactionBatchUpdateWithOptions (0.02s)
    request_id_header_test.go:1157: unaryClientCall is incorrect; got=5 want=4
--- FAIL: TestRequestIDHeader_ClientBatchWriteWithError (0.02s)
    request_id_header_test.go:840: unaryClientCall is incorrect; got=2 want=1
--- FAIL: TestRequestIDHeader_PartitionQueryWithError (0.03s)
    request_id_header_test.go:973: unaryClientCall is incorrect; got=5 want=4
--- FAIL: TestRequestIDHeader_clientBatchWrite (0.02s)
    request_id_header_test.go:711: unaryClientCall is incorrect; got=2 want=1
--- FAIL: TestRequestIDHeader_ClientBatchWriteWithSessionNotFound (0.04s)
    request_id_header_test.go:775: unaryClientCall is incorrect; got=2 want=1
--- FAIL: TestRequestIDHeader_PartitionQueryWithoutError (0.04s)
    request_id_header_test.go:1015: unaryClientCall is incorrect; got=5 want=4
--- FAIL: TestRequestIDHeader_BatchDMLWithMultipleDML (0.03s)
    request_id_header_test.go:653: unaryClientCall is incorrect; got=7 want=6
--- FAIL: TestRequestIDHeader_retriesOnSessionNotFound (0.04s)
    request_id_header_test.go:573: unaryClientCall is incorrect; got=7 want=8
--- FAIL: TestRequestIDHeader_RetryOnAbortAndValidate (0.60s)
    request_id_header_test.go:1351: unaryClientCall is incorrect; got=7 want=6
    request_id_header_test.go:1376: RequestID segments mismatch: got - want +
          []*spanner.requestIDSegments{
          	&{
          		... // 2 identical fields
          		ClientID:  57,
          		RequestNo: 1,
        - 		ChannelID: 2,
        + 		ChannelID: 1,
          		RPCNo:     1,
          	},
          	&{Version: 1, ProcessID: "10766896037511722208", ClientID: 57, RequestNo: 2, ...},
          	&{Version: 1, ProcessID: "10766896037511722208", ClientID: 57, RequestNo: 3, ...},
          	&{
          		Version:   1,
          		ProcessID: "10766896037511722208",
          		ClientID:  57,
        - 		RequestNo: 4,
        + 		RequestNo: 3,
          		ChannelID: 1,
        - 		RPCNo:     1,
        + 		RPCNo:     2,
          	},
          	&{
          		Version:   1,
          		ProcessID: "10766896037511722208",
          		ClientID:  57,
        - 		RequestNo: 4,
        + 		RequestNo: 3,
          		ChannelID: 1,
        - 		RPCNo:     2,
        + 		RPCNo:     3,
          	},
          	&{
          		Version:   1,
          		ProcessID: "10766896037511722208",
          		ClientID:  57,
        - 		RequestNo: 4,
        + 		RequestNo: 3,
          		ChannelID: 1,
        - 		RPCNo:     3,
        + 		RPCNo:     4,
          	},
        - 	s"1.10766896037511722208.57.1.4.4",
          }
FAIL
exit status 1
FAIL	cloud.google.com/go/spanner	5.210s

Remedies

• Firstly don't block main with test failures by skipping request-id tests when the environment variable is set per PR test(spanner): temporarily skip TestRequestIDHeader if using multiplexedSessions #11309
• Send a code patch to account for the oddities with multiplexed sessions