Allow empty partial column in copy from clause (#5180)

Author: acquamarin

scripts/antlr4/Cypher.g4

@@ -259,10 +259,10 @@ oC_Statement
         | kU_UseDatabase;
 
 kU_CopyFrom
-    : COPY SP oC_SchemaName ( ( SP? kU_ColumnNames SP? ) | SP ) FROM SP kU_ScanSource ( SP? '(' SP? kU_Options SP? ')' )? ;
+    : COPY SP oC_SchemaName ( SP? '(' SP? kU_ColumnNames? ')' )? SP FROM SP kU_ScanSource ( SP? '(' SP? kU_Options SP? ')' )? ;
 
 kU_ColumnNames
-     : '(' SP? oC_SchemaName ( SP? ',' SP? oC_SchemaName )* SP? ')';
+     : oC_SchemaName ( SP? ',' SP? oC_SchemaName )* SP? ;
 
 kU_ScanSource
     : kU_FilePaths

scripts/antlr4/hash.md5

@@ -1 +1 @@
-0ebee60341e5e8e1203a6c8cb1b35151
+dc70036c7f774248132e8946275ffc3a

src/antlr4/Cypher.g4

@@ -28,10 +28,10 @@ oC_Statement
         | kU_UseDatabase;
 
 kU_CopyFrom
-    : COPY SP oC_SchemaName ( ( SP? kU_ColumnNames SP? ) | SP ) FROM SP kU_ScanSource ( SP? '(' SP? kU_Options SP? ')' )? ;
+    : COPY SP oC_SchemaName ( SP? '(' SP? kU_ColumnNames? ')' )? SP FROM SP kU_ScanSource ( SP? '(' SP? kU_Options SP? ')' )? ;
 
 kU_ColumnNames
-     : '(' SP? oC_SchemaName ( SP? ',' SP? oC_SchemaName )* SP? ')';
+     : oC_SchemaName ( SP? ',' SP? oC_SchemaName )* SP? ;
 
 kU_ScanSource
     : kU_FilePaths

test/test_files/copy/copy_partial_column.test

@@ -14,6 +14,13 @@
 ---- ok
 -STATEMENT COPY person FROM "${KUZU_ROOT_DIRECTORY}/dataset/tinysnb/vPerson.csv";
 ---- ok
+-STATEMENT CREATE REL TABLE sees(FROM person to person);
+---- ok
+-STATEMENT COPY sees() FROM (LOAD FROM "${KUZU_ROOT_DIRECTORY}/dataset/tinysnb/eKnows.csv" RETURN column0, column1);
+---- ok
+-STATEMENT MATCH ()-[e:sees]->() RETURN count(e)
+---- 1
+6
 -STATEMENT CREATE REL TABLE knows1 (FROM person TO person, nullDouble DOUBLE, date DATE, meetTime TIMESTAMP,
      validInterval INTERVAL, comments STRING[], summary STRUCT(locations STRING[],
     transfer STRUCT(day DATE, amount INT64[])), notes UNION(firstmet DATE, type INT16, comment STRING), someMap MAP(STRING, STRING), MANY_MANY);