Improve parsing of multi-character sequences. Fixes #563

Author: bgrainger

src/MySqlConnector/Core/SqlParser.cs

@@ -133,12 +133,12 @@ public void Parse(string sql)
 					if (state != State.Beginning && state != State.Statement)
 						throw new InvalidOperationException("Unexpected state: {0}".FormatInvariant(state));
 
-					if (ch == '-')
+					if (ch == '-' && index < sql.Length - 2 && sql[index + 1] == '-' && sql[index + 2] == ' ')
 					{
 						beforeCommentState = state;
 						state = State.Hyphen;
 					}
-					else if (ch == '/')
+					else if (ch == '/' && index < sql.Length - 1 && sql[index + 1] == '*')
 						state = State.ForwardSlash;
 					else if (ch == '\'')
 						state = State.SingleQuotedString;

tests/MySqlConnector.Tests/StatementPreparerTests.cs

@@ -23,6 +23,27 @@ public void Bug429(string sql)
 			Assert.Equal(sql.Replace("@param", "123"), parsedSql);
 		}
 
+		[Theory]
+		[InlineData("UPDATE table SET a=a-@b;")]
+		[InlineData("UPDATE table SET a=a-/* subtract b */@b;")]
+		[InlineData("UPDATE table SET a=a+@b;")]
+		[InlineData("UPDATE table SET a=a/@b;")]
+		[InlineData("UPDATE table SET a=a-- \n-@b;")]
+		[InlineData("UPDATE table SET a = a-@b;")]
+		[InlineData("UPDATE table SET a = a+@b;")]
+		[InlineData("UPDATE table SET a = a - @b;")]
+		[InlineData("UPDATE table SET a=@b-a;")]
+		[InlineData("UPDATE table SET a=@b+a;")]
+		[InlineData("UPDATE table SET a = @b-a;")]
+		[InlineData("UPDATE table SET a = @b - a;")]
+		public void Bug563(string sql)
+		{
+			var parameters = new MySqlParameterCollection();
+			parameters.AddWithValue("@b", 123);
+			var parsedSql = GetParsedSql(sql, parameters);
+			Assert.Equal(sql.Replace("@b", "123"), parsedSql);
+		}
+
 		[Theory]
 		[InlineData(@"SELECT /* * / @param */ 1;")]
 		[InlineData("SELECT # @param \n1;")]