vim-patch:8.0.0201: completion of highlight groups includes cleared names

Problem:    When completing a group name for a highlight or syntax command
            cleared groups are included.
Solution:   Skip groups that have been cleared.

d61e8aaae5

src/nvim/syntax.c

@@ -52,6 +52,7 @@ static bool did_syntax_onoff = false;
 struct hl_group {
   char_u      *sg_name;         ///< highlight group name
   char_u      *sg_name_u;       ///< uppercase of sg_name
+  int sg_cleared;       	///< "hi clear" was used
   int sg_attr;                  ///< Screen attr @see ATTR_ENTRY
   int sg_link;                  ///< link to this highlight group ID
   int sg_set;                   ///< combination of flags in \ref SG_SET
@@ -6490,6 +6491,7 @@ void do_highlight(const char *line, const bool forceit, const bool init)
           HL_TABLE()[from_id - 1].sg_set |= SG_LINK;
         HL_TABLE()[from_id - 1].sg_link = to_id;
         HL_TABLE()[from_id - 1].sg_scriptID = current_SID;
+	HL_TABLE()[from_id - 1].sg_cleared = false;
         redraw_all_later(SOME_VALID);
       }
     }
@@ -6872,6 +6874,7 @@ void do_highlight(const char *line, const bool forceit, const bool init)
         error = true;
         break;
       }
+      HL_TABLE()[idx].sg_cleared = false;
 
       // When highlighting has been given for a group, don't link it.
       if (!init || !(HL_TABLE()[idx].sg_set & SG_LINK)) {
@@ -6953,6 +6956,8 @@ static int hl_has_settings(int idx, int check_link)
  */
 static void highlight_clear(int idx)
 {
+  HL_TABLE()[idx].sg_cleared = true;
+
   HL_TABLE()[idx].sg_attr = 0;
   HL_TABLE()[idx].sg_cterm = 0;
   HL_TABLE()[idx].sg_cterm_bold = FALSE;
@@ -7763,10 +7768,20 @@ const char *get_highlight_name(expand_T *const xp, const int idx)
   } else if (idx == highlight_ga.ga_len + include_none + include_default + 1
              && include_link != 0) {
     return "clear";
-  } else if (idx < 0 || idx >= highlight_ga.ga_len) {
+  } else if (idx < 0) {
     return NULL;
   }
-  return (const char *)HL_TABLE()[idx].sg_name;
+
+  /* Items are never removed from the table, skip the ones that were cleared.
+   */
+  int current_idx = idx; 
+  while (current_idx < highlight_ga.ga_len && HL_TABLE()[current_idx].sg_cleared) {
+      ++current_idx;
+  }
+  if (current_idx >= highlight_ga.ga_len) {
+      return NULL;
+  }
+  return (const char *)HL_TABLE()[current_idx].sg_name;
 }
 
 color_name_table_T color_name_table[] = {

src/nvim/testdir/test_syntax.vim

@@ -152,6 +152,12 @@ func Test_syntax_completion()
   call feedkeys(":syn sync \<C-A>\<C-B>\"\<CR>", 'tx')
   call assert_equal('"syn sync ccomment clear fromstart linebreaks= linecont lines= match maxlines= minlines= region', @:)
 
+  " Check that clearing "Aap" avoids it showing up before Boolean.
+  hi Aap ctermfg=blue
+  call feedkeys(":syn list \<C-A>\<C-B>\"\<CR>", 'tx')
+  call assert_match('^"syn list Aap Boolean Character ', @:)
+  hi clear Aap
+
   call feedkeys(":syn list \<C-A>\<C-B>\"\<CR>", 'tx')
   call assert_match('^"syn list Boolean Character ', @:)
 
@@ -188,11 +194,11 @@ func Test_syntax_arg_skipped()
   syntax conceal off
   call assert_match('conceal off', execute('syntax conceal'))
 
-  syntax region Tar start=/</ end=/>/
+  syntax region Bar start=/</ end=/>/
   if 0
     syntax region NotTest start=/</ end=/>/ contains=@Spell
   endif
-  call assert_match('Tar', execute('syntax'))
+  call assert_match('Bar', execute('syntax'))
   call assert_notmatch('NotTest', execute('syntax'))
   call assert_notmatch('Spell', execute('syntax'))
 
@@ -202,6 +208,8 @@ func Test_syntax_arg_skipped()
     syntax rest
   endif
   call assert_equal(a, execute('hi Foo'))
+  hi clear Bar
+  hi clear Foo
 
   set ft=tags
   syn off
@@ -283,8 +291,7 @@ func Test_syntax_arg_skipped()
   endif
   call assert_match('on C-style comments', execute('syntax sync'))
   call assert_match('maximal 5 lines', execute('syntax sync'))
-  syn clear
-  syn keyword Foo foo
+  syn sync clear
   if 0
     syn sync ccomment
   endif
@@ -292,3 +299,33 @@ func Test_syntax_arg_skipped()
 
   syn clear
 endfunc
+ 
+func Test_invalid_arg()
+  call assert_fails('syntax case asdf', 'E390:')
+  call assert_fails('syntax conceal asdf', 'E390:')
+  call assert_fails('syntax spell asdf', 'E390:')
+endfunc
+
+func Test_syn_sync()
+  syntax region HereGroup start=/this/ end=/that/
+  syntax sync match SyncHere grouphere HereGroup "pattern"
+  call assert_match('SyncHere', execute('syntax sync'))
+  syn sync clear
+  call assert_notmatch('SyncHere', execute('syntax sync'))
+  syn clear
+endfunc
+
+func Test_syn_clear()
+  syntax keyword Foo foo
+  syntax keyword Bar tar
+  call assert_match('Foo', execute('syntax'))
+  call assert_match('Bar', execute('syntax'))
+  syn clear Foo
+  call assert_notmatch('Foo', execute('syntax'))
+  call assert_match('Bar', execute('syntax'))
+  syn clear Foo Bar
+  call assert_notmatch('Foo', execute('syntax'))
+  call assert_notmatch('Bar', execute('syntax'))
+  hi clear Foo
+  hi clear Bar
+endfunc