Merge pull request #3147 from dolthub/elianddb/3144-fix-trace-parse-exceptions

#3144 - Fix parseErr tracing to show error messages instead of memory addresses

Author: elianddb

sql/planbuilder/builder.go

@@ -205,6 +205,10 @@ type parseErr struct {
 	err error
 }
 
+func (p parseErr) Error() string {
+	return p.err.Error()
+}
+
 func (b *Builder) handleErr(err error) {
 	panic(parseErr{err})
 }

sql/planbuilder/parse_test.go

@@ -3014,3 +3014,26 @@ func TestPlanBuilderErr(t *testing.T) {
 		})
 	}
 }
+
+// TestParseErrImplementsError verifies that parseErr implements the error interface (issue #3144)
+// This ensures that when parseErr structs are logged directly (like in tracing), they show
+// actual error messages instead of memory addresses like "{0xc006f85d80}"
+func TestParseErrImplementsError(t *testing.T) {
+	// Create a parseErr directly to test the Error() method implementation
+	originalErr := sql.ErrColumnNotFound.New("test_column", "test_table")
+	pErr := parseErr{err: originalErr}
+
+	// Test that parseErr implements the error interface
+	var _ error = pErr
+
+	// Test that Error() returns the underlying error message
+	require.Equal(t, originalErr.Error(), pErr.Error())
+
+	// Test that when formatted as string, it shows meaningful content
+	formatted := fmt.Sprintf("%v", pErr)
+	require.Contains(t, formatted, "test_column")
+	require.NotContains(t, formatted, "0x", "Should not show memory address")
+
+	// Test that the error message is not a struct format
+	require.NotContains(t, formatted, "{github.com/dolthub/go-mysql-server/sql/planbuilder.parseErr")
+}