patchdb path validation

Author: JayT106

cmd/cronosd/cmd/patch_db.go

@@ -227,7 +227,12 @@ Examples:
 				if len(validDBNames) == 1 {
 					dbTargetPath = targetPath
 				} else {
-					// For multiple databases, treat targetPath as data directory
+					// For multiple databases, validate that targetPath is a directory, not a *.db file
+					cleanedTargetPath := filepath.Clean(targetPath)
+					if filepath.Ext(cleanedTargetPath) == ".db" {
+						return fmt.Errorf("when patching multiple databases, --target-path must be a data directory (e.g., ~/.cronos/data), not a *.db file path (got %q); remove the .db suffix", targetPath)
+					}
+					// Treat targetPath as data directory
 					dbTargetPath = filepath.Join(targetPath, dbName+".db")
 				}
 

cmd/cronosd/cmd/patch_db_test.go

@@ -0,0 +1,92 @@
+package cmd
+
+import (
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+// TestTargetPathValidation tests that multi-database patching rejects *.db file paths
+func TestTargetPathValidation(t *testing.T) {
+	tests := []struct {
+		name        string
+		targetPath  string
+		dbCount     int
+		shouldError bool
+		errorString string
+	}{
+		{
+			name:        "single DB with .db extension - allowed",
+			targetPath:  "/path/to/blockstore.db",
+			dbCount:     1,
+			shouldError: false,
+		},
+		{
+			name:        "single DB without .db extension - allowed (will be validated later)",
+			targetPath:  "/path/to/blockstore",
+			dbCount:     1,
+			shouldError: false,
+		},
+		{
+			name:        "multiple DBs with data directory - allowed",
+			targetPath:  "/path/to/data",
+			dbCount:     2,
+			shouldError: false,
+		},
+		{
+			name:        "multiple DBs with .db file path - rejected",
+			targetPath:  "/path/to/blockstore.db",
+			dbCount:     2,
+			shouldError: true,
+			errorString: "must be a data directory",
+		},
+		{
+			name:        "multiple DBs with .db file path (trailing slash) - rejected",
+			targetPath:  "/path/to/blockstore.db/",
+			dbCount:     2,
+			shouldError: true,
+			errorString: "must be a data directory",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Simulate the validation logic from patch_db.go
+			var dbNames []string
+			for i := 0; i < tt.dbCount; i++ {
+				dbNames = append(dbNames, "testdb")
+			}
+
+			var err error
+			if len(dbNames) == 1 {
+				// Single DB: no validation in this branch
+				_ = tt.targetPath
+			} else {
+				// Multiple DBs: validate targetPath is not a *.db file
+				cleanedTargetPath := filepath.Clean(tt.targetPath)
+				if filepath.Ext(cleanedTargetPath) == ".db" {
+					err = &targetPathError{path: tt.targetPath}
+				}
+			}
+
+			if tt.shouldError {
+				require.Error(t, err)
+				if tt.errorString != "" {
+					require.Contains(t, err.Error(), tt.errorString)
+				}
+			} else {
+				require.NoError(t, err)
+			}
+		})
+	}
+}
+
+// targetPathError is a helper type to simulate the error from patch_db.go
+type targetPathError struct {
+	path string
+}
+
+func (e *targetPathError) Error() string {
+	return "when patching multiple databases, --target-path must be a data directory (e.g., ~/.cronos/data), not a *.db file path (got \"" + e.path + "\"); remove the .db suffix"
+}