patch 9.0.1198: abstract class not supported yetv9.0.1198

Problem:    Abstract class not supported yet.
Solution:   Implement abstract class and add tests.

4 files changed, 58 insertions, 12 deletions

diff --git a/src/errors.h b/src/errors.h
index de1ae4bd03..3b6307f0ba 100644
--- a/src/errors.h
+++ b/src/errors.h
@@ -3440,4 +3440,6 @@ EXTERN char e_using_super_not_in_class_function[]
 	INIT(= N_("E1357: Using \"super\" not in a class function"));
 EXTERN char e_using_super_not_in_child_class[]
 	INIT(= N_("E1358: Using \"super\" not in a child class"));
+EXTERN char e_cannot_define_new_function_in_abstract_class[]
+	INIT(= N_("E1359: Cannot define a \"new\" function in an abstract class"));
 #endif
diff --git a/src/testdir/test_vim9_class.vim b/src/testdir/test_vim9_class.vim
index a6caad2fce..4a2b87c740 100644
--- a/src/testdir/test_vim9_class.vim
+++ b/src/testdir/test_vim9_class.vim
@@ -1014,5 +1014,40 @@ def Test_class_import()
   v9.CheckScriptSuccess(lines)
 enddef
 
+def Test_abstract_class()
+  var lines =<< trim END
+      vim9script
+      abstract class Base
+        this.name: string
+      endclass
+      class Person extends Base
+        this.age: number
+      endclass
+      var p: Base = Person.new('Peter', 42)
+      assert_equal('Peter', p.name)
+      assert_equal(42, p.age)
+  END
+  v9.CheckScriptSuccess(lines)
+
+  lines =<< trim END
+      vim9script
+      abstract class Base
+        this.name: string
+      endclass
+      class Person extends Base
+        this.age: number
+      endclass
+      var p = Base.new('Peter')
+  END
+  v9.CheckScriptFailure(lines, 'E1325: Method not found on class "Base": new(')
+
+  lines =<< trim END
+      abstract class Base
+        this.name: string
+      endclass
+  END
+  v9.CheckScriptFailure(lines, 'E1316:')
+enddef
+
 
 " vim: ts=8 sw=2 sts=2 expandtab tw=80 fdm=marker
diff --git a/src/version.c b/src/version.c
index 52eabb5807..763c79d91c 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1198,
+/**/
     1197,
 /**/
     1196,
diff --git a/src/vim9class.c b/src/vim9class.c
index d66fa3ecc4..8dcd92b6eb 100644
--- a/src/vim9class.c
+++ b/src/vim9class.c
@@ -204,17 +204,6 @@ ex_class(exarg_T *eap)
 {
     int is_class = eap->cmdidx == CMD_class;  // FALSE for :interface
 
-    if (!current_script_is_vim9()
-		|| (cmdmod.cmod_flags & CMOD_LEGACY)
-		|| !getline_equal(eap->getline, eap->cookie, getsourceline))
-    {
-	if (is_class)
-	    emsg(_(e_class_can_only_be_defined_in_vim9_script));
-	else
-	    emsg(_(e_interface_can_only_be_defined_in_vim9_script));
-	return;
-    }
-
     char_u *arg = eap->arg;
     int is_abstract = eap->cmdidx == CMD_abstract;
     if (is_abstract)
@@ -225,6 +214,18 @@ ex_class(exarg_T *eap)
 	    return;
 	}
 	arg = skipwhite(arg + 5);
+	is_class = TRUE;
+    }
+
+    if (!current_script_is_vim9()
+		|| (cmdmod.cmod_flags & CMOD_LEGACY)
+		|| !getline_equal(eap->getline, eap->cookie, getsourceline))
+    {
+	if (is_class)
+	    emsg(_(e_class_can_only_be_defined_in_vim9_script));
+	else
+	    emsg(_(e_interface_can_only_be_defined_in_vim9_script));
+	return;
     }
 
     if (!ASCII_ISUPPER(*arg))
@@ -493,6 +494,12 @@ early_ret:
 	    {
 		char_u *name = uf->uf_name;
 		int is_new = STRNCMP(name, "new", 3) == 0;
+		if (is_new && is_abstract)
+		{
+		    emsg(_(e_cannot_define_new_function_in_abstract_class));
+		    success = FALSE;
+		    break;
+		}
 		garray_T *fgap = has_static || is_new
 					       ? &classfunctions : &objmethods;
 		// Check the name isn't used already.
@@ -826,7 +833,7 @@ early_ret:
 		have_new = TRUE;
 		break;
 	    }
-	if (is_class && !have_new)
+	if (is_class && !is_abstract && !have_new)
 	{
 	    // No new() method was defined, add the default constructor.
 	    garray_T fga;