Ignore empty statements.

Author: loveleif

cypher-shell/src/main/java/org/neo4j/shell/CypherShell.java

@@ -51,6 +51,7 @@ public class CypherShell implements StatementExecuter, Connector, TransactionHan
 {
     // Final space to catch newline
     protected static final Pattern cmdNamePattern = Pattern.compile( "^\\s*(?<name>[^\\s]+)\\b(?<args>.*)\\s*$" );
+    private static final Pattern emptyStatementPattern = Pattern.compile( "^\\s*;$" );
     protected final Map<String, ParamValue> queryParams = new HashMap<>();
     private final LinePrinter linePrinter;
     private final BoltStateHandler boltStateHandler;
@@ -90,6 +91,11 @@ protected static String stripTrailingSemicolons( @Nonnull String text )
     @Override
     public void execute( @Nonnull final String cmdString ) throws ExitException, CommandException
     {
+        if ( isEmptyStatement( cmdString ) )
+        {
+            return;
+        }
+
         // See if it's a shell command
         final Optional<CommandExecutable> cmd = getCommandExecutable( cmdString );
         if ( cmd.isPresent() )
@@ -107,6 +113,11 @@ public void execute( @Nonnull final String cmdString ) throws ExitException, Com
         executeCypher( cmdString );
     }
 
+    private static boolean isEmptyStatement( final String statement )
+    {
+        return emptyStatementPattern.matcher( statement ).matches();
+    }
+
     /**
      * Executes a piece of text as if it were Cypher. By default, all of the cypher is executed in single statement (with an implicit transaction).
      *

cypher-shell/src/test/java/org/neo4j/shell/CypherShellTest.java

@@ -330,4 +330,13 @@ public void setParameterDoesNotTriggerByBoltError() throws CommandException
         Object result = shell.setParameter( "bob", "99" );
         assertEquals( 99L, result );
     }
+
+    @Test
+    public void ignoreEmptyStatement() throws CommandException
+    {
+        when( mockedBoltStateHandler.runCypher( anyString(), anyMap() ) ).thenThrow( new IllegalStateException( "Test failed" ) );
+        OfflineTestShell shell = new OfflineTestShell( logger, mockedBoltStateHandler, mockedPrettyPrinter );
+
+        shell.execute( "  \t;" );
+    }
 }