Abort expression parsing after encountering a maximum of 10 errors

nyalldawson · nyalldawson · commit 23b76efe90d4 · 2018-07-30T15:42:15.000+10:00
Fixes #19480 (cherry-picked from 3c8b156)
diff --git a/src/core/qgsexpressionparser.yy b/src/core/qgsexpressionparser.yy
@@ -31,6 +31,9 @@
 // don't redeclare malloc/free
 #define YYINCLUDED_STDLIB_H 1
 
+// maximum number of errors encountered before parser aborts
+#define MAX_ERRORS 10
+
 struct expression_parser_context;
 #include "qgsexpressionparser.hpp"
 
@@ -177,7 +180,10 @@ root: expression { parser_ctx->rootNode = $1; }
     | error expression
         {
             delete $2;
-            yyerrok;
+            if ( parser_ctx->parserErrors.count() < MAX_ERRORS )
+              yyerrok;
+            else
+              YYABORT;
         }
    ;
 
diff --git a/tests/src/core/testqgsexpression.cpp b/tests/src/core/testqgsexpression.cpp
@@ -287,6 +287,14 @@ class TestQgsExpression: public QObject
       QCOMPARE( exp.parserErrors().first().lastColumn, lastColumn );
     }
 
+    void max_errors()
+    {
+      QgsExpression e( "wkt_geom&#x9;OBJECTID&#x9;id&#x9;a&#x9;b&#x9;c&#x9;d&#x9;e&#x9;f&#x9;g&#x9;h&#x9;i&#x9;j&#x9;k&#x9;l&#x9;m&#x9;n&#x9;o&#x9;p&#x9;q&#x9;r&#x9;" );
+      QVERIFY( e.hasParserError() );
+      // want parsing to abort after a maximum of 10 errors
+      QCOMPARE( e.parserErrors().count(), 10 );
+    }
+
     void parsing_with_locale()
     {
       // check that parsing of numbers works correctly even when using some other locale

Original file line number	Diff line number	Diff line change
`@@ -31,6 +31,9 @@`
`31`	`31`	`// don't redeclare malloc/free`
`32`	`32`	`#define YYINCLUDED_STDLIB_H 1`
`33`	`33`
	`34`	`+// maximum number of errors encountered before parser aborts`
	`35`	`+#define MAX_ERRORS 10`
	`36`	`+`
`34`	`37`	`struct expression_parser_context;`
`35`	`38`	`#include "qgsexpressionparser.hpp"`
`36`	`39`
`@@ -177,7 +180,10 @@ root: expression { parser_ctx->rootNode = $1; }`
`177`	`180`	`\| error expression`
`178`	`181`	`{`
`179`	`182`	`delete $2;`
`180`		`- yyerrok;`
	`183`	`+ if ( parser_ctx->parserErrors.count() < MAX_ERRORS )`
	`184`	`+ yyerrok;`
	`185`	`+ else`
	`186`	`+ YYABORT;`
`181`	`187`	`}`
`182`	`188`	`;`
`183`	`189`
Original file line number	Diff line number	Diff line change
`@@ -287,6 +287,14 @@ class TestQgsExpression: public QObject`
`287`	`287`	`QCOMPARE( exp.parserErrors().first().lastColumn, lastColumn );`
`288`	`288`	`}`
`289`	`289`
	`290`	`+ void max_errors()`
	`291`	`+ {`
	`292`	`+ QgsExpression e( "wkt_geom OBJECTID id a b c d e f g h i j k l m n o p q r " );`
	`293`	`+ QVERIFY( e.hasParserError() );`
	`294`	`+ // want parsing to abort after a maximum of 10 errors`
	`295`	`+ QCOMPARE( e.parserErrors().count(), 10 );`
	`296`	`+ }`
	`297`	`+`
`290`	`298`	`void parsing_with_locale()`
`291`	`299`	`{`
`292`	`300`	`// check that parsing of numbers works correctly even when using some other locale`