patch 9.0.1879: Vim9: incorrect duplicate class member detection

Problem:  Vim9: incorrect duplicate class member detection
Solution: Incorrect duplicate class member detection when variable names
          have the same prefix.  Not able to access class member variables
          using an object. Fix coding style issues

closes: #13042

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Yegappan Lakshmanan <yegappan@yahoo.com>

src/testdir/test_vim9_class.vim

@@ -3790,6 +3790,16 @@ def Test_dup_member_variable()
     endclass
   END
   v9.CheckScriptFailure(lines, 'E1369: Duplicate member: val')
+
+  # Two member variables with a common prefix
+  lines =<< trim END
+    vim9script
+    class A
+      public static svar2: number
+      public static svar: number
+    endclass
+  END
+  v9.CheckScriptSuccess(lines)
 enddef
 
 def Test_interface_static_member_access()
@@ -4084,4 +4094,39 @@ def Test_modify_class_member_from_def_function()
   v9.CheckScriptSuccess(lines)
 enddef
 
+" Test for accessing a class member variable using an object
+def Test_class_member_access_using_object()
+  var lines =<< trim END
+    vim9script
+    class A
+      public static svar1: list<number> = [1]
+      public static svar2: list<number> = [2]
+    endclass
+
+    A.svar1->add(3)
+    A.svar2->add(4)
+    assert_equal([1, 3], A.svar1)
+    assert_equal([2, 4], A.svar2)
+    var a1 = A.new()
+    a1.svar1->add(5)
+    a1.svar2->add(6)
+    assert_equal([1, 3, 5], a1.svar1)
+    assert_equal([2, 4, 6], a1.svar2)
+
+    def Foo()
+      A.svar1->add(7)
+      A.svar2->add(8)
+      assert_equal([1, 3, 5, 7], A.svar1)
+      assert_equal([2, 4, 6, 8], A.svar2)
+      var a2 = A.new()
+      a2.svar1->add(9)
+      a2.svar2->add(10)
+      assert_equal([1, 3, 5, 7, 9], a2.svar1)
+      assert_equal([2, 4, 6, 8, 10], a2.svar2)
+    enddef
+    Foo()
+  END
+  v9.CheckScriptSuccess(lines)
+enddef
+
 " vim: ts=8 sw=2 sts=2 expandtab tw=80 fdm=marker

src/version.c

@@ -699,6 +699,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1879,
 /**/
     1878,
 /**/

src/vim9class.c

@@ -584,8 +584,8 @@ check_func_arg_names(
 		// Check all the class member names
 		for (int mi = 0; mi < mgap->ga_len; ++mi)
 		{
-		    char_u *mname = ((ocmember_T *)mgap->ga_data + mi)
-			->ocm_name;
+		    char_u *mname =
+				((ocmember_T *)mgap->ga_data + mi)->ocm_name;
 		    if (STRCMP(aname, mname) == 0)
 		    {
 			if (uf->uf_script_ctx.sc_sid > 0)
@@ -610,22 +610,24 @@ check_func_arg_names(
     static int
 is_duplicate_member(garray_T *mgap, char_u *varname, char_u *varname_end)
 {
-    char_u *pstr = (*varname == '_') ? varname + 1 : varname;
+    char_u	*name = vim_strnsave(varname, varname_end - varname);
+    char_u	*pstr = (*name == '_') ? name + 1 : name;
+    int		dup = FALSE;
 
     for (int i = 0; i < mgap->ga_len; ++i)
     {
 	ocmember_T *m = ((ocmember_T *)mgap->ga_data) + i;
 	char_u	*qstr = *m->ocm_name == '_' ? m->ocm_name + 1 : m->ocm_name;
-	if (STRNCMP(pstr, qstr, varname_end - pstr) == 0)
+	if (STRCMP(pstr, qstr) == 0)
 	{
-	    char_u *name = vim_strnsave(varname, varname_end - varname);
 	    semsg(_(e_duplicate_member_str), name);
-	    vim_free(name);
-	    return TRUE;
+	    dup = TRUE;
+	    break;
 	}
     }
 
-    return FALSE;
+    vim_free(name);
+    return dup;
 }
 
 /*
@@ -735,8 +737,7 @@ update_member_method_lookup_table(
 	for (int cl_i = 0; cl_i < objmethods->ga_len; ++cl_i)
 	{
 	    if (STRCMP(ifcl->class_obj_methods[if_i]->uf_name,
-			((ufunc_T **)objmethods->ga_data)[cl_i]->uf_name)
-		    == 0)
+			((ufunc_T **)objmethods->ga_data)[cl_i]->uf_name) == 0)
 	    {
 		int *table = (int *)(if2cl + 1);
 		table[if_i] = cl_i;
@@ -1030,9 +1031,9 @@ ex_class(exarg_T *eap)
 {
     int		is_class = eap->cmdidx == CMD_class;  // FALSE for :interface
     long	start_lnum = SOURCING_LNUM;
-
     char_u	*arg = eap->arg;
     int		is_abstract = eap->cmdidx == CMD_abstract;
+
     if (is_abstract)
     {
 	if (STRNCMP(arg, "class", 5) != 0 || !VIM_ISWHITE(arg[5]))
@@ -1670,6 +1671,57 @@ ex_type(exarg_T *eap UNUSED)
     // TODO
 }
 
+/*
+ * Returns OK if a member variable named "name" is present in the class "cl".
+ * Otherwise returns FAIL.  If found, the member variable typval is set in
+ * "rettv".  If "is_object" is TRUE, then the object member variable table is
+ * searched.  Otherwise the class member variable table is searched.
+ */
+    static int
+get_member_tv(
+    class_T	*cl,
+    int		is_object,
+    char_u	*name,
+    size_t	namelen,
+    typval_T	*rettv)
+{
+    int member_count = is_object ? cl->class_obj_member_count
+						: cl->class_class_member_count;
+    ocmember_T *members = is_object ? cl->class_obj_members
+						: cl->class_class_members;
+
+    for (int i = 0; i < member_count; ++i)
+    {
+	ocmember_T *m = &members[i];
+	if (STRNCMP(name, m->ocm_name, namelen) == 0
+						&& m->ocm_name[namelen] == NUL)
+	{
+	    if (*name == '_')
+	    {
+		semsg(_(e_cannot_access_private_member_str), m->ocm_name);
+		return FAIL;
+	    }
+
+	    // The object only contains a pointer to the class, the member
+	    // values array follows right after that.
+	    object_T *obj = rettv->vval.v_object;
+	    if (is_object)
+	    {
+		typval_T *tv = (typval_T *)(obj + 1) + i;
+		copy_tv(tv, rettv);
+	    }
+	    else
+		copy_tv(&cl->class_members_tv[i], rettv);
+
+	    object_unref(obj);
+
+	    return OK;
+	}
+    }
+
+    return FAIL;
+}
+
 /*
  * Evaluate what comes after a class:
  * - class member: SomeClass.varname
@@ -1791,28 +1843,14 @@ class_object_index(
 
     else if (rettv->v_type == VAR_OBJECT)
     {
-	for (int i = 0; i < cl->class_obj_member_count; ++i)
+	// Search in the object member variable table and the class member
+	// variable table.
+	if (get_member_tv(cl, TRUE, name, len, rettv) == OK
+		|| get_member_tv(cl, FALSE, name, len, rettv) == OK)
 	{
-	    ocmember_T *m = &cl->class_obj_members[i];
-	    if (STRNCMP(name, m->ocm_name, len) == 0 && m->ocm_name[len] == NUL)
-	    {
-		if (*name == '_')
-		{
-		    semsg(_(e_cannot_access_private_member_str), m->ocm_name);
-		    return FAIL;
-		}
-
-		// The object only contains a pointer to the class, the member
-		// values array follows right after that.
-		object_T *obj = rettv->vval.v_object;
-		typval_T *tv = (typval_T *)(obj + 1) + i;
-		copy_tv(tv, rettv);
-		object_unref(obj);
-
 	    *arg = name_end;
 	    return OK;
 	}
-	}
 
 	semsg(_(e_member_not_found_on_object_str_str), cl->class_name, name);
     }