Sql Expressions: State when error is from GMS (#102112)

pkg/expr/sql/db.go

@@ -4,6 +4,7 @@ package sql
 
 import (
 	"context"
+	"fmt"
 
 	sqle "github.com/dolthub/go-mysql-server"
 	mysql "github.com/dolthub/go-mysql-server/sql"
@@ -15,6 +16,42 @@ import (
 // DB is a database that can execute SQL queries against a set of Frames.
 type DB struct{}
 
+// GoMySQLServerError represents an error from the underlying Go MySQL Server
+type GoMySQLServerError struct {
+	Err error
+}
+
+// Error implements the error interface
+func (e *GoMySQLServerError) Error() string {
+	return fmt.Sprintf("error in go-mysql-server: %v", e.Err)
+}
+
+// Unwrap provides the original error for errors.Is/As
+func (e *GoMySQLServerError) Unwrap() error {
+	return e.Err
+}
+
+// WrapGoMySQLServerError wraps errors from Go MySQL Server with additional context
+func WrapGoMySQLServerError(err error) error {
+	// Don't wrap nil errors
+	if err == nil {
+		return nil
+	}
+
+	// Check if it's a function not found error or other specific GMS errors
+	if isFunctionNotFoundError(err) {
+		return &GoMySQLServerError{Err: err}
+	}
+
+	// Return original error if it's not one we want to wrap
+	return err
+}
+
+// isFunctionNotFoundError checks if the error is related to a function not being found
+func isFunctionNotFoundError(err error) bool {
+	return mysql.ErrFunctionNotFound.Is(err)
+}
+
 // QueryFrames runs the sql query query against a database created from frames, and returns the frame.
 // The RefID of each frame becomes a table in the database.
 // It is expected that there is only one frame per RefID.
@@ -47,7 +84,7 @@ func (db *DB) QueryFrames(ctx context.Context, name string, query string, frames
 
 	schema, iter, _, err := engine.Query(mCtx, query)
 	if err != nil {
-		return nil, err
+		return nil, WrapGoMySQLServerError(err)
 	}
 
 	f, err := convertToDataFrame(mCtx, iter, schema)

pkg/expr/sql/db_test.go

@@ -193,6 +193,18 @@ func TestQueryFramesDateTimeSelect(t *testing.T) {
 	}
 }
 
+func TestErrorsFromGoMySQLServerAreFlagged(t *testing.T) {
+	const GmsNotImplemented = "STDDEV" // not implemented in go-mysql-server as of 2025-03-18
+
+	db := DB{}
+
+	query := `SELECT ` + GmsNotImplemented + `(1);`
+
+	_, err := db.QueryFrames(context.Background(), "sqlExpressionRefId", query, nil)
+	require.Error(t, err)
+	require.Contains(t, err.Error(), "error in go-mysql-server")
+}
+
 // p is a utility for pointers from constants
 func p[T any](v T) *T {
 	return &v

pkg/expr/sql/parser_allow_test.go

@@ -129,7 +129,17 @@ var example_case_statement = `SELECT
   END AS category
 FROM metrics`
 
-var example_all_allowed_functions = `SELECT
+var example_all_allowed_functions = `WITH sample_data AS (
+  SELECT 
+    100 AS value,
+    'example' AS name,
+    NOW() AS created_at
+  UNION ALL SELECT 
+    50 AS value,
+    'test' AS name,
+    DATE_SUB(NOW(), INTERVAL 1 DAY) AS created_at
+)
+SELECT
   -- Conditional functions
   IF(value > 100, 'High', 'Low') AS conditional_if,
   COALESCE(value, 0) AS conditional_coalesce,
@@ -191,6 +201,6 @@ var example_all_allowed_functions = `SELECT
   -- Type conversion
   CAST(value AS CHAR) AS type_cast,
   CONVERT(value, CHAR) AS type_convert
-FROM metrics
+FROM sample_data
 GROUP BY name, value, created_at
 LIMIT 10`