Only continue if possible, otherwise do nothing

This is needed because some plans do not use loops for find entities.
neo4j · Nov 29, 2018 · 076d2de · 076d2de
1 parent f28f49b
commit 076d2de
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Showing 3 changed files with 19 additions and 8 deletions.
diff --git a/community/codegen/src/main/java/org/neo4j/codegen/CodeBlock.java b/community/codegen/src/main/java/org/neo4j/codegen/CodeBlock.java
@@ -33,24 +33,32 @@ public class CodeBlock implements AutoCloseable
     private MethodEmitter emitter;
     private final CodeBlock parent;
     private boolean done;
+    private boolean continuableBlock;
 
     protected LocalVariables localVariables = new LocalVariables();
 
     CodeBlock( CodeBlock parent )
+    {
+        this( parent, parent.continuableBlock );
+    }
+
+    CodeBlock( CodeBlock parent, boolean continuableBlock )
     {
         this.clazz = parent.clazz;
         this.emitter = parent.emitter;
         parent.emitter = InvalidState.IN_SUB_BLOCK;
         this.parent = parent;
         //copy over local variables from parent
         this.localVariables = copy( parent.localVariables );
+        this.continuableBlock = continuableBlock;
     }
 
     CodeBlock( ClassGenerator clazz, MethodEmitter emitter, Parameter... parameters )
     {
         this.clazz = clazz;
         this.emitter = emitter;
         this.parent = null;
+        this.continuableBlock = false;
         localVariables.createNew( clazz.handle(), "this" );
         for ( Parameter parameter : parameters )
         {
@@ -162,7 +170,7 @@ public CodeBlock forEach( Parameter local, Expression iterable )
     public CodeBlock whileLoop( Expression test )
     {
         emitter.beginWhile( test );
-        return new CodeBlock( this );
+        return new CodeBlock( this, true );
     }
 
     public CodeBlock ifStatement( Expression test )
@@ -192,9 +200,12 @@ public void returns( Expression value )
         emitter.returns( value );
     }
 
-    public void continues()
+    public void continueIfPossible()
     {
-        emitter.continues();
+        if ( continuableBlock )
+        {
+            emitter.continues();
+        }
     }
 
     public void throwException( Expression exception )

diff --git a/community/codegen/src/test/java/org/neo4j/codegen/CodeGenerationTest.java b/community/codegen/src/test/java/org/neo4j/codegen/CodeGenerationTest.java
@@ -605,7 +605,7 @@ public void shouldGenerateWhileLoopContinue() throws Throwable
 
                     try ( CodeBlock ifBlock = loop.ifStatement( loop.load( "skip" ) ) )
                     {
-                        ifBlock.continues();
+                        ifBlock.continueIfPossible();
                     }
 
                     loop.expression( invoke(
@@ -667,7 +667,7 @@ public void shouldGenerateNestedWhileLoopInnerContinue() throws Throwable
 
                         try ( CodeBlock ifBlock = inner.ifStatement( inner.load( "skip" ) ) )
                         {
-                            ifBlock.continues();
+                            ifBlock.continueIfPossible();
                         }
 
                         inner.expression( invoke(
@@ -736,7 +736,7 @@ public void shouldGenerateNestedWhileLoopDoubleContinue() throws Throwable
 
                     try ( CodeBlock ifBlock = outer.ifStatement( outer.load( "skipOuter" ) ) )
                     {
-                        ifBlock.continues();
+                        ifBlock.continueIfPossible();
                     }
 
                     try ( CodeBlock inner = outer.whileLoop( invoke( outer.load( "targets" ),
@@ -756,7 +756,7 @@ public void shouldGenerateNestedWhileLoopDoubleContinue() throws Throwable
 
                         try ( CodeBlock ifBlock = inner.ifStatement( inner.load( "skipInner" ) ) )
                         {
-                            ifBlock.continues();
+                            ifBlock.continueIfPossible();
                         }
 
                         inner.expression( invoke(

diff --git a/...e/cypher/cypher/src/main/scala/org/neo4j/cypher/internal/spi/v3_4/codegen/Templates.scala b/...e/cypher/cypher/src/main/scala/org/neo4j/cypher/internal/spi/v3_4/codegen/Templates.scala
@@ -120,7 +120,7 @@ object Templates {
     }, new Consumer[CodeBlock] {
       override def accept(innerError: CodeBlock): Unit = {
         result = onFailure(innerError)
-        innerError.continues()
+        innerError.continueIfPossible()
       }
     }, param[EntityNotFoundException]("enf"))
     result