vim-patch:7.4.1707

Problem:    Cannot use empty dictionary key, even though it can be useful.
Solution:   Allow using an empty dictionary key.

0921ecff1c

src/nvim/eval.c

@@ -2145,11 +2145,9 @@ get_lval (
 
     if (lp->ll_tv->v_type == VAR_DICT) {
       if (len == -1) {
-        /* "[key]": get key from "var1" */
-        key = get_tv_string(&var1);             /* is number or string */
-        if (*key == NUL) {
-          if (!quiet)
-            EMSG(_(e_emptykey));
+        // "[key]": get key from "var1"
+        key = get_tv_string_chk(&var1);  // is number or string
+        if (key == NULL) {
           clear_tv(&var1);
           return NULL;
         }
@@ -4600,10 +4598,8 @@ eval_index (
         dictitem_T  *item;
 
         if (len == -1) {
-          key = get_tv_string(&var1);
-          if (*key == NUL) {
-            if (verbose)
-              EMSG(_(e_emptykey));
+          key = get_tv_string_chk(&var1);
+          if (key == NULL) {
             clear_tv(&var1);
             return FAIL;
           }
@@ -6587,10 +6583,8 @@ static int get_dict_tv(char_u **arg, typval_T *rettv, int evaluate)
     }
     if (evaluate) {
       key = get_tv_string_buf_chk(&tvkey, buf);
-      if (key == NULL || *key == NUL) {
-        /* "key" is NULL when get_tv_string_buf_chk() gave an errmsg */
-        if (key != NULL)
-          EMSG(_(e_emptykey));
+      if (key == NULL) {
+        // "key" is NULL when get_tv_string_buf_chk() gave an errmsg
         clear_tv(&tvkey);
         goto failret;
       }

src/nvim/hashtab.c

@@ -368,8 +368,7 @@ hash_T hash_hash(char_u *key)
   hash_T hash = *key;
 
   if (hash == 0) {
-    // Empty keys are not allowed, but we don't want to crash if we get one.
-    return (hash_T) 0;
+    return (hash_T)0;
   }
 
   // A simplistic algorithm that appears to do very well.

src/nvim/testdir/test_expr.vim

@@ -23,3 +23,17 @@ func Test_strcharpart()
 
   call assert_equal('a', strcharpart('axb', -1, 2))
 endfunc
+
+func Test_dict()
+  let d = {'': 'empty', 'a': 'a', 0: 'zero'}
+  call assert_equal('empty', d[''])
+  call assert_equal('a', d['a'])
+  call assert_equal('zero', d[0])
+  call assert_true(has_key(d, ''))
+  call assert_true(has_key(d, 'a'))
+
+  let d[''] = 'none'
+  let d['a'] = 'aaa'
+  call assert_equal('none', d[''])
+  call assert_equal('aaa', d['a'])
+endfunc

src/nvim/version.c

@@ -737,7 +737,7 @@ static int included_patches[] = {
   // 1710,
   // 1709 NA
   // 1708,
-  // 1707,
+  1707,
   // 1706 NA
   // 1705 NA
   1704,