metamorphic: fix code around WAL recovery directories

Author: RaduBerinde

metamorphic/meta.go

@@ -241,7 +241,7 @@ func RunAndCompare(t *testing.T, rootDir string, rOpts ...RunOption) {
 		cmd := exec.Command(binary, args...)
 		out, err := cmd.CombinedOutput()
 		if err != nil {
-			t.Fatalf(`
+			t.Fatalf(`error running %v
 ===== SEED =====
 %d
 ===== ERR =====
@@ -255,6 +255,7 @@ func RunAndCompare(t *testing.T, rootDir string, rOpts ...RunOption) {
 ===== HISTORY =====
 %s
 To reduce:  go test ./internal/metamorphic -tags invariants -run '%s$' --run-dir %s --try-to-reduce -v`,
+				cmd.String(),
 				runOpts.seed,
 				err,
 				out,
@@ -523,13 +524,13 @@ func RunOnce(t TestingT, runDir string, seed uint64, historyPath string, rOpts .
 		testOpts.Threads = runOpts.maxThreads
 	}
 
-	dir := opts.FS.PathJoin(runDir, "data")
+	dataDir := opts.FS.PathJoin(runDir, "data")
 	// Set up the initial database state if configured to start from a non-empty
 	// database. By default tests start from an empty database, but split
 	// version testing may configure a previous metamorphic tests's database
 	// state as the initial state.
 	if testOpts.initialStatePath != "" {
-		require.NoError(t, setupInitialState(dir, testOpts))
+		require.NoError(t, setupInitialState(dataDir, testOpts))
 	}
 
 	if testOpts.Opts.WALFailover != nil {
@@ -561,7 +562,7 @@ func RunOnce(t TestingT, runDir string, seed uint64, historyPath string, rOpts .
 	defer h.Close()
 
 	m := newTest(ops)
-	require.NoError(t, m.init(h, dir, testOpts, runOpts.numInstances, runOpts.opTimeout))
+	require.NoError(t, m.init(h, dataDir, testOpts, runOpts.numInstances, runOpts.opTimeout))
 
 	if err := Execute(m); err != nil {
 		fmt.Fprintf(os.Stderr, "Seed: %d\n", seed)

metamorphic/options.go

@@ -953,27 +953,50 @@ func setupInitialState(dataDir string, testOpts *TestOptions) error {
 	// If the test opts are not configured to use a WAL dir, we add the WAL dir
 	// as a 'WAL recovery dir' so that we'll read any WALs in the directory in
 	// Open.
-	walRecoveryPath := testOpts.Opts.FS.PathJoin(dataDir, "wal")
-	if testOpts.Opts.WALDir != "" {
-		// If the test opts are configured to use a WAL dir, we add the data
-		// directory itself as a 'WAL recovery dir' so that we'll read any WALs if
-		// the previous test was writing them to the data directory.
-		walRecoveryPath = dataDir
-	}
-	testOpts.Opts.WALRecoveryDirs = append(testOpts.Opts.WALRecoveryDirs, wal.Dir{
-		FS:      testOpts.Opts.FS,
-		Dirname: walRecoveryPath,
-	})
-
-	// If the failover dir exists and the test opts are not configured to use
-	// WAL failover, add the failover directory as a 'WAL recovery dir' in case
-	// the previous test was configured to use failover.
+	fs := testOpts.Opts.FS
+	walRecoveryPath := fs.PathJoin(dataDir, "wal")
+	if _, err := fs.Stat(walRecoveryPath); err == nil {
+		// Previous test used a WAL dir.
+		if testOpts.Opts.WALDir == "" {
+			// This test is not using a WAL dir. Add the previous WAL dir as a
+			// recovery dir.
+			testOpts.Opts.WALRecoveryDirs = append(testOpts.Opts.WALRecoveryDirs, wal.Dir{
+				FS:      fs,
+				Dirname: pebble.MakeStoreRelativePath(fs, "wal"),
+			})
+		} else {
+			// Both the previous test and the current test are using a WAL dir. We
+			// assume that they are the same.
+			if testOpts.Opts.WALDir != pebble.MakeStoreRelativePath(fs, "wal") {
+				return errors.Errorf("unsupported wal dir value %q", testOpts.Opts.WALDir)
+			}
+		}
+	} else {
+		// Previous test did not use a WAL dir.
+		if testOpts.Opts.WALDir != "" {
+			// The current test is using a WAL dir; we add the data directory itself
+			// as a 'WAL recovery dir' so that we'll read any WALs if the previous
+			// test was writing them to the data directory.
+			testOpts.Opts.WALRecoveryDirs = append(testOpts.Opts.WALRecoveryDirs, wal.Dir{
+				FS:      fs,
+				Dirname: pebble.MakeStoreRelativePath(fs, ""),
+			})
+		}
+	}
+
+	// If the previous test used WAL failover and this test does not use failover,
+	// add the failover directory as a 'WAL recovery dir' in case the previous
+	// test was configured to use failover.
 	failoverDir := testOpts.Opts.FS.PathJoin(dataDir, "wal_secondary")
-	if _, err := testOpts.Opts.FS.Stat(failoverDir); err == nil && testOpts.Opts.WALFailover == nil {
-		testOpts.Opts.WALRecoveryDirs = append(testOpts.Opts.WALRecoveryDirs, wal.Dir{
-			FS:      testOpts.Opts.FS,
-			Dirname: failoverDir,
-		})
+	if _, err := testOpts.Opts.FS.Stat(failoverDir); err == nil {
+		if testOpts.Opts.WALFailover == nil {
+			testOpts.Opts.WALRecoveryDirs = append(testOpts.Opts.WALRecoveryDirs, wal.Dir{
+				FS:      testOpts.Opts.FS,
+				Dirname: pebble.MakeStoreRelativePath(testOpts.Opts.FS, "wal_secondary"),
+			})
+		} else if testOpts.Opts.WALFailover.Secondary.Dirname != pebble.MakeStoreRelativePath(testOpts.Opts.FS, "wal_secondary") {
+			return errors.Errorf("unsupported wal failover dir value %q", testOpts.Opts.WALFailover.Secondary.Dirname)
+		}
 	}
 	return nil
 }

options.go

@@ -2191,6 +2191,8 @@ func (o *Options) CheckCompatibility(previousOptions string) error {
 			}
 		case "Options.wal_dir", "WAL Failover.secondary_dir":
 			switch {
+			case value == "":
+				return nil
 			case o.WALDir == value:
 				return nil
 			case o.WALFailover != nil && o.WALFailover.Secondary.Dirname == value: