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diff src/vim9compile.c @ 33260:aba1fa2b7d1e v9.0.1898

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patch 9.0.1898: Vim9: restrict access to static vars Commit: https://github.com/vim/vim/commit/c30a90d9b2c029f794cea502f6b824f71e4876dd Author: Yegappan Lakshmanan <yegappan@yahoo.com> Date: Fri Sep 15 20:14:55 2023 +0200 patch 9.0.1898: Vim9: restrict access to static vars Problem: Vim9: restrict access to static vars and methods Solution: Class members are accesible only from the class where they are defined. Based on the #13004 discussion, the following changes are made: 1) Static variables and methods are accessible only using the class name and inside the class where they are defined. 2) Static variables and methods can be used without the class name in the class where they are defined. 3) Static variables of a super class are not copied to the sub class. 4) A sub class can declare a class variable with the same name as the super class. 5) When a method or member is found during compilation, use more specific error messages. This aligns the Vim9 class variable/method implementation with the Dart implementation. Also while at it, ignore duplicate class and object methods. The access level of an object method can however be changed in a subclass. For the tests, use the new CheckSourceFailure() function instead of the CheckScriptFailure() function in the tests. closes: #13086 Signed-off-by: Christian Brabandt <cb@256bit.org> Co-authored-by: Yegappan Lakshmanan <yegappan@yahoo.com>
author Christian Brabandt <cb@256bit.org>
date Fri, 15 Sep 2023 20:30:05 +0200
parents 575dd775b7fb
children 0c3553cfe22e
line wrap: on
line diff
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -332,24 +332,42 @@ script_var_exists(char_u *name, size_t l
 }
 
 /*
- * If "name[len]" is a class method in cctx->ctx_ufunc->uf_class return the
- * class method index.
+ * Returns the index of a class method or class variable with name "name"
+ * accessible in the currently compiled function.
  * If "cl_ret" is not NULL set it to the class.
  * Otherwise return -1.
  */
-    int
-cctx_class_method_idx(
+    static int
+cctx_class_midx(
     cctx_T  *cctx,
+    int	    is_method,
     char_u  *name,
     size_t  len,
     class_T **cl_ret)
 {
     if (cctx == NULL || cctx->ctx_ufunc == NULL
-	    || cctx->ctx_ufunc->uf_class == NULL)
+	    || cctx->ctx_ufunc->uf_class == NULL
+	    || cctx->ctx_ufunc->uf_defclass == NULL)
 	return -1;
 
-    class_T *cl = cctx->ctx_ufunc->uf_class;
-    int m_idx = class_method_idx(cl, name, len);
+    // Search for the class method or variable in the class where the calling
+    // function is defined.
+    class_T *cl = cctx->ctx_ufunc->uf_defclass;
+    int m_idx = is_method ? class_method_idx(cl, name, len)
+					: class_member_idx(cl, name, len);
+    if (m_idx < 0)
+    {
+	cl = cl->class_extends;
+	while (cl != NULL)
+	{
+	    m_idx = is_method ? class_method_idx(cl, name, len)
+					: class_member_idx(cl, name, len);
+	    if (m_idx >= 0)
+		break;
+	    cl = cl->class_extends;
+	}
+    }
+
     if (m_idx >= 0)
     {
 	if (cl_ret != NULL)
@@ -360,10 +378,24 @@ cctx_class_method_idx(
 }
 
 /*
- * If "name[len]" is a class member in cctx->ctx_ufunc->uf_class return the
- * class member variable index.
- * If "cl_ret" is not NULL set it to the class.
- * Otherwise return -1;
+ * Returns the index of a class method with name "name" accessible in the
+ * currently compiled function.  Returns -1 if not found.  The class where the
+ * method is defined is returned in "cl_ret".
+ */
+    int
+cctx_class_method_idx(
+    cctx_T  *cctx,
+    char_u  *name,
+    size_t  len,
+    class_T **cl_ret)
+{
+    return cctx_class_midx(cctx, TRUE, name, len, cl_ret);
+}
+
+/*
+ * Returns the index of a class variable with name "name" accessible in the
+ * currently compiled function.  Returns -1 if not found.  The class where the
+ * variable is defined is returned in "cl_ret".
  */
     int
 cctx_class_member_idx(
@@ -372,19 +404,7 @@ cctx_class_member_idx(
     size_t  len,
     class_T **cl_ret)
 {
-    if (cctx == NULL || cctx->ctx_ufunc == NULL
-	    || cctx->ctx_ufunc->uf_class == NULL)
-	return -1;
-
-    class_T *cl = cctx->ctx_ufunc->uf_class;
-    int m_idx = class_member_idx(cl, name, len);
-    if (m_idx >= 0)
-    {
-	if (cl_ret != NULL)
-	    *cl_ret = cl;
-    }
-
-    return m_idx;
+    return cctx_class_midx(cctx, FALSE, name, len, cl_ret);
 }
 
 /*
@@ -1639,6 +1659,8 @@ compile_lhs(
 	}
 	else
 	{
+	    class_T	*defcl;
+
 	    // No specific kind of variable recognized, just a name.
 	    if (check_reserved_name(lhs->lhs_name, lhs->lhs_has_index
 						&& *var_end == '.') == FAIL)
@@ -1681,8 +1703,16 @@ compile_lhs(
 		}
 	    }
 	    else if ((lhs->lhs_classmember_idx = cctx_class_member_idx(
-			    cctx, var_start, lhs->lhs_varlen, NULL)) >= 0)
+			    cctx, var_start, lhs->lhs_varlen, &defcl)) >= 0)
 	    {
+		if (cctx->ctx_ufunc->uf_defclass != defcl)
+		{
+		    // A class variable can be accessed without the class name
+		    // only inside a class.
+		    semsg(_(e_class_member_str_accessible_only_inside_class_str),
+			    lhs->lhs_name, defcl->class_name);
+		    return FAIL;
+		}
 		if (is_decl)
 		{
 		    semsg(_(e_variable_already_declared_in_class_str),
@@ -1918,10 +1948,10 @@ compile_lhs(
 
 	int use_class = lhs->lhs_type != NULL
 			    && (lhs->lhs_type->tt_type == VAR_CLASS
-				       || lhs->lhs_type->tt_type == VAR_OBJECT);
+				    || lhs->lhs_type->tt_type == VAR_OBJECT);
 	if (lhs->lhs_type == NULL
 		|| (use_class ? lhs->lhs_type->tt_class == NULL
-					   : lhs->lhs_type->tt_member == NULL))
+		    : lhs->lhs_type->tt_member == NULL))
 	{
 	    lhs->lhs_member_type = &t_any;
 	}
@@ -1930,9 +1960,10 @@ compile_lhs(
 	    // for an object or class member get the type of the member
 	    class_T	*cl = lhs->lhs_type->tt_class;
 	    ocmember_T	*m;
+	    int		is_object = lhs->lhs_type->tt_type == VAR_OBJECT;
 
 	    lhs->lhs_member_type = class_member_type(cl,
-					lhs->lhs_type->tt_type == VAR_OBJECT,
+					is_object,
 					after + 1, lhs->lhs_end,
 					&lhs->lhs_member_idx, &m);
 	    if (lhs->lhs_member_idx < 0)
@@ -1946,7 +1977,11 @@ compile_lhs(
 	    }
 	    // If it is private member variable, then accessing it outside the
 	    // class is not allowed.
-	    if ((m->ocm_access != VIM_ACCESS_ALL) && !inside_class(cctx, cl))
+	    // If it is a read only class variable, then it can be modified
+	    // only inside the class where it is defined.
+	    if ((m->ocm_access != VIM_ACCESS_ALL) &&
+		    ((is_object && !inside_class(cctx, cl))
+		     || (!is_object && cctx->ctx_ufunc->uf_class != cl)))
 	    {
 		char *msg = (m->ocm_access == VIM_ACCESS_PRIVATE)
 				? e_cannot_access_private_member_str