Patch 8.2.1473

[Bram Moolenaar]

Patch 8.2.1473
Problem: Items in a list given to :const can still be modified.
Solution: Work like ":lockvar! name" but don't lock referenced items.
Make locking a blob work.
Files: runtime/doc/eval.txt, src/evalvars.c, src/eval.c,
src/testdir/test_const.vim


*** ../vim-8.2.1472/runtime/doc/eval.txt 2020-08-15 18:38:32.072814243 +0200
--- runtime/doc/eval.txt 2020-08-17 20:39:11.291181532 +0200
***************
*** 12201,12210 ****
:const x = 1
< is equivalent to: >
:let x = 1
! :lockvar 1 x
< This is useful if you want to make sure the variable
! is not modified.
! *E995*
|:const| does not allow to for changing a variable: >
:let x = 1
:const x = 2 " Error!
--- 12264,12281 ----
:const x = 1
< is equivalent to: >
:let x = 1
! :lockvar! x
< This is useful if you want to make sure the variable
! is not modified. If the value is a List or Dictionary
! literal then the items also cannot be changed: >
! const ll = [1, 2, 3]
! let ll[1] = 5 " Error!
! < Nested references are not locked: >
! let lvar = ['a']
! const lconst = [0, lvar]
! let lconst[0] = 2 " Error!
! let lconst[1][0] = 'b' " OK
! < *E995*
|:const| does not allow to for changing a variable: >
:let x = 1
:const x = 2 " Error!
*** ../vim-8.2.1472/src/evalvars.c 2020-08-16 22:49:57.393356184 +0200
--- src/evalvars.c 2020-08-17 20:41:59.898237787 +0200
***************
*** 173,179 ****
static char_u *ex_let_one(char_u *arg, typval_T *tv, int copy, int flags, char_u *endchars, char_u *op);
static int do_unlet_var(lval_T *lp, char_u *name_end, exarg_T *eap, int deep, void *cookie);
static int do_lock_var(lval_T *lp, char_u *name_end, exarg_T *eap, int deep, void *cookie);
! static void item_lock(typval_T *tv, int deep, int lock);
static void delete_var(hashtab_T *ht, hashitem_T *hi);
static void list_one_var(dictitem_T *v, char *prefix, int *first);
static void list_one_var_a(char *prefix, char_u *name, int type, char_u *string, int *first);
--- 173,179 ----
static char_u *ex_let_one(char_u *arg, typval_T *tv, int copy, int flags, char_u *endchars, char_u *op);
static int do_unlet_var(lval_T *lp, char_u *name_end, exarg_T *eap, int deep, void *cookie);
static int do_lock_var(lval_T *lp, char_u *name_end, exarg_T *eap, int deep, void *cookie);
! static void item_lock(typval_T *tv, int deep, int lock, int check_refcount);
static void delete_var(hashtab_T *ht, hashitem_T *hi);
static void list_one_var(dictitem_T *v, char *prefix, int *first);
static void list_one_var_a(char *prefix, char_u *name, int type, char_u *string, int *first);
***************
*** 1703,1709 ****
di->di_flags |= DI_FLAGS_LOCK;
else
di->di_flags &= ~DI_FLAGS_LOCK;
! item_lock(&di->di_tv, deep, lock);
}
}
*name_end = cc;
--- 1703,1709 ----
di->di_flags |= DI_FLAGS_LOCK;
else
di->di_flags &= ~DI_FLAGS_LOCK;
! item_lock(&di->di_tv, deep, lock, FALSE);
}
}
*name_end = cc;
***************
*** 1715,1740 ****
// (un)lock a range of List items.
while (li != NULL && (lp->ll_empty2 || lp->ll_n2 >= lp->ll_n1))
{
! item_lock(&li->li_tv, deep, lock);
li = li->li_next;
++lp->ll_n1;
}
}
else if (lp->ll_list != NULL)
// (un)lock a List item.
! item_lock(&lp->ll_li->li_tv, deep, lock);
else
// (un)lock a Dictionary item.
! item_lock(&lp->ll_di->di_tv, deep, lock);

return ret;
}

/*
* Lock or unlock an item. "deep" is nr of levels to go.
*/
static void
! item_lock(typval_T *tv, int deep, int lock)
{
static int recurse = 0;
list_T *l;
--- 1715,1742 ----
// (un)lock a range of List items.
while (li != NULL && (lp->ll_empty2 || lp->ll_n2 >= lp->ll_n1))
{
! item_lock(&li->li_tv, deep, lock, FALSE);
li = li->li_next;
++lp->ll_n1;
}
}
else if (lp->ll_list != NULL)
// (un)lock a List item.
! item_lock(&lp->ll_li->li_tv, deep, lock, FALSE);
else
// (un)lock a Dictionary item.
! item_lock(&lp->ll_di->di_tv, deep, lock, FALSE);

return ret;
}

/*
* Lock or unlock an item. "deep" is nr of levels to go.
+ * When "check_refcount" is TRUE do not lock a list or dict with a reference
+ * count larger than 1.
*/
static void
! item_lock(typval_T *tv, int deep, int lock, int check_refcount)
{
static int recurse = 0;
list_T *l;
***************
*** 1776,1782 ****
break;

case VAR_BLOB:
! if ((b = tv->vval.v_blob) != NULL)
{
if (lock)
b->bv_lock |= VAR_LOCKED;
--- 1778,1785 ----
break;

case VAR_BLOB:
! if ((b = tv->vval.v_blob) != NULL
! && !(check_refcount && b->bv_refcount > 1))
{
if (lock)
b->bv_lock |= VAR_LOCKED;
***************
*** 1785,1791 ****
}
break;
case VAR_LIST:
! if ((l = tv->vval.v_list) != NULL)
{
if (lock)
l->lv_lock |= VAR_LOCKED;
--- 1788,1795 ----
}
break;
case VAR_LIST:
! if ((l = tv->vval.v_list) != NULL
! && !(check_refcount && l->lv_refcount > 1))
{
if (lock)
l->lv_lock |= VAR_LOCKED;
***************
*** 1794,1804 ****
if ((deep < 0 || deep > 1) && l->lv_first != &range_list_item)
// recursive: lock/unlock the items the List contains
FOR_ALL_LIST_ITEMS(l, li)
! item_lock(&li->li_tv, deep - 1, lock);
}
break;
case VAR_DICT:
! if ((d = tv->vval.v_dict) != NULL)
{
if (lock)
d->dv_lock |= VAR_LOCKED;
--- 1798,1809 ----
if ((deep < 0 || deep > 1) && l->lv_first != &range_list_item)
// recursive: lock/unlock the items the List contains
FOR_ALL_LIST_ITEMS(l, li)
! item_lock(&li->li_tv, deep - 1, lock, check_refcount);
}
break;
case VAR_DICT:
! if ((d = tv->vval.v_dict) != NULL
! && !(check_refcount && d->dv_refcount > 1))
{
if (lock)
d->dv_lock |= VAR_LOCKED;
***************
*** 1813,1819 ****
if (!HASHITEM_EMPTY(hi))
{
--todo;
! item_lock(&HI2DI(hi)->di_tv, deep - 1, lock);
}
}
}
--- 1818,1825 ----
if (!HASHITEM_EMPTY(hi))
{
--todo;
! item_lock(&HI2DI(hi)->di_tv, deep - 1, lock,
! check_refcount);
}
}
}
***************
*** 3087,3093 ****
}

if (flags & LET_IS_CONST)
! item_lock(&di->di_tv, 1, TRUE);
}

/*
--- 3093,3102 ----
}

if (flags & LET_IS_CONST)
! // Like :lockvar! name: lock the value and what it contains, but only
! // if the reference count is up to one. That locks only literal
! // values.
! item_lock(&di->di_tv, DICT_MAXNEST, TRUE, TRUE);
}

/*
*** ../vim-8.2.1472/src/eval.c 2020-08-16 18:42:50.678811797 +0200
--- src/eval.c 2020-08-17 20:58:12.160440884 +0200
***************
*** 1218,1223 ****
--- 1218,1225 ----
semsg(_(e_letwrong), op);
return;
}
+ if (var_check_lock(lp->ll_blob->bv_lock, lp->ll_name, FALSE))
+ return;

if (lp->ll_range && rettv->v_type == VAR_BLOB)
{
*** ../vim-8.2.1472/src/testdir/test_const.vim 2020-08-16 22:49:57.393356184 +0200
--- src/testdir/test_const.vim 2020-08-17 20:47:56.420170904 +0200
***************
*** 273,292 ****
call assert_fails('const {s2} = "bar"', 'E995:')
endfunc

! func Test_lock_depth_is_1()
! const l = [1, 2, 3]
! const d = {'foo': 10}
!
! " Modify list - setting item is OK, adding/removing items not
! let l[0] = 42
call assert_fails('call add(l, 4)', 'E741:')
call assert_fails('unlet l[1]', 'E741:')

! " Modify dict - changing item is OK, adding/removing items not
! let d['foo'] = 'hello'
! let d.foo = 44
call assert_fails("let d['bar'] = 'hello'", 'E741:')
call assert_fails("unlet d['foo']", 'E741:')
endfunc

" vim: shiftwidth=2 sts=2 expandtab
--- 273,307 ----
call assert_fails('const {s2} = "bar"', 'E995:')
endfunc

! func Test_lock_depth_is_2()
! " Modify list - error when changing item or adding/removing items
! const l = [1, 2, [3, 4]]
! call assert_fails('let l[0] = 42', 'E741:')
! call assert_fails('let l[2][0] = 42', 'E741:')
call assert_fails('call add(l, 4)', 'E741:')
call assert_fails('unlet l[1]', 'E741:')

! " Modify blob - error when changing
! const b = 0z001122
! call assert_fails('let b[0] = 42', 'E741:')
!
! " Modify dict - error when changing item or adding/removing items
! const d = {'foo': 10}
! call assert_fails("let d['foo'] = 'hello'", 'E741:')
! call assert_fails("let d.foo = 'hello'", 'E741:')
call assert_fails("let d['bar'] = 'hello'", 'E741:')
call assert_fails("unlet d['foo']", 'E741:')
+
+ " Modifying list or dict item contents is OK.
+ let lvar = ['a', 'b']
+ let bvar = 0z1122
+ const l2 = [0, lvar, bvar]
+ let l2[1][0] = 'c'
+ let l2[2][1] = 0x33
+ call assert_equal([0, ['c', 'b'], 0z1133], l2)
+
+ const d2 = #{a: 0, b: lvar, c: 4}
+ let d2.b[1] = 'd'
endfunc

" vim: shiftwidth=2 sts=2 expandtab
*** ../vim-8.2.1472/src/version.c 2020-08-17 19:34:06.961427079 +0200
--- src/version.c 2020-08-17 19:56:12.945187908 +0200
***************
*** 756,757 ****
--- 756,759 ----
{ /* Add new patch number below this line */
+ /**/
+ 1473,
/**/

--
hundred-and-one symptoms of being an internet addict:
225. You sign up for free subscriptions for all the computer magazines

/// Bram Moolenaar -- Br...@Moolenaar.net -- http://www.Moolenaar.net \\\
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