Query: Throw better exception message for non-composable SQL in FromSql

Resolves #17558
dotnet · Oct 10, 2019 · df0d72c · df0d72c
1 parent 1ceabe8
commit df0d72c
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Showing 5 changed files with 107 additions and 201 deletions.
diff --git a/src/EFCore.Relational/Properties/RelationalStrings.Designer.cs b/src/EFCore.Relational/Properties/RelationalStrings.Designer.cs
diff --git a/src/EFCore.Relational/Properties/RelationalStrings.resx b/src/EFCore.Relational/Properties/RelationalStrings.resx
@@ -494,4 +494,7 @@
   <data name="SetOperationNotWithinEntityTypeHierarchy" xml:space="preserve">
     <value>Set operations (Union, Concat, Intersect, Except) are only supported over entity types within the same type hierarchy.</value>
   </data>
-</root>
+  <data name="FromSqlNonComposable" xml:space="preserve">
+    <value>FromSqlRaw/FromSqlInterpolated API is being used with non-composable SQL but query is composing over it. Considering using `AsEnumerable` after FromSqlRaw/FromSqlInterpolated method to avoid composing on server side.</value>
+  </data>
+</root>
diff --git a/src/EFCore.Relational/Query/QuerySqlGenerator.cs b/src/EFCore.Relational/Query/QuerySqlGenerator.cs
@@ -5,6 +5,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Linq.Expressions;
+using Microsoft.EntityFrameworkCore.Diagnostics;
 using Microsoft.EntityFrameworkCore.Query.SqlExpressions;
 using Microsoft.EntityFrameworkCore.Storage;
 using Microsoft.EntityFrameworkCore.Storage.Internal;
@@ -312,6 +313,11 @@ protected override Expression VisitFromSql(FromSqlExpression fromSqlExpression)
         {
             _relationalCommandBuilder.AppendLine("(");
 
+            if (!IsComposableSql(fromSqlExpression.Sql))
+            {
+                throw new InvalidOperationException(RelationalStrings.FromSqlNonComposable);
+            }
+
             using (_relationalCommandBuilder.Indent())
             {
                 GenerateFromSql(fromSqlExpression);
@@ -324,6 +330,15 @@ protected override Expression VisitFromSql(FromSqlExpression fromSqlExpression)
             return fromSqlExpression;
         }
 
+        private bool IsComposableSql(string sql)
+        {
+            var trimmedSql = sql.TrimStart('\r', '\n', '\t', ' ');
+
+            return trimmedSql.StartsWith("SELECT ", StringComparison.OrdinalIgnoreCase)
+                || trimmedSql.StartsWith("SELECT" + Environment.NewLine, StringComparison.OrdinalIgnoreCase)
+                || trimmedSql.StartsWith("SELECT\t", StringComparison.OrdinalIgnoreCase);
+        }
+
         protected override Expression VisitSqlBinary(SqlBinaryExpression sqlBinaryExpression)
         {
             if (sqlBinaryExpression.OperatorType == ExpressionType.Coalesce)