patch 8.0.0517: there is no way to remove quickfix lists

Problem:    There is no way to remove quickfix lists (for testing).
Solution:   Add the 'f' action to setqflist(). Add tests. (Yegappan
            Lakshmanan)

runtime/doc/eval.txt

@@ -6936,16 +6936,19 @@ setqflist({list} [, {action}[, {what}]])		*setqflist()*
 		Note that the list is not exactly the same as what
 		|getqflist()| returns.
 
-							*E927*
+		{action} values:				*E927*
-		If {action} is set to 'a', then the items from {list} are
+		'a'	The items from {list} are added to the existing
-		added to the existing quickfix list. If there is no existing
+			quickfix list. If there is no existing list, then a
-		list, then a new list is created.
+			new list is created.
 		
-		If {action} is set to 'r', then the items from the current
+		'r'	The items from the current quickfix list are replaced
-		quickfix list are replaced with the items from {list}.  This
+			with the items from {list}.  This can also be used to
-		can also be used to clear the list: >
+			clear the list: >
-			:call setqflist([], 'r')
+				:call setqflist([], 'r')
 <	
+		'f'	All the quickfix lists in the quickfix stack are
+			freed.
+
 		If {action} is not present or is set to ' ', then a new list
 		is created.
 

src/evalfunc.c

@@ -10038,7 +10038,8 @@ set_qf_ll_list(
 	    act = get_tv_string_chk(action_arg);
 	    if (act == NULL)
 		return;		/* type error; errmsg already given */
-	    if ((*act == 'a' || *act == 'r' || *act == ' ') && act[1] == NUL)
+	    if ((*act == 'a' || *act == 'r' || *act == ' ' || *act == 'f') &&
+		    act[1] == NUL)
 		action = *act;
 	    else
 		EMSG2(_(e_invact), act);

src/quickfix.c

@@ -717,7 +717,8 @@ qf_get_next_file_line(qfstate_T *state)
 
 #ifdef FEAT_MBYTE
     /* Convert a line if it contains a non-ASCII character. */
-    if (state->vc.vc_type != CONV_NONE && has_non_ascii(state->linebuf)) {
+    if (state->vc.vc_type != CONV_NONE && has_non_ascii(state->linebuf))
+    {
 	char_u	*line;
 
 	line = string_convert(&state->vc, state->linebuf, &state->linelen);
@@ -917,7 +918,8 @@ restofline:
 	    }
 	    if (fmt_ptr->flags == '+' && !qi->qf_multiscan)	/* %+ */
 	    {
-		if (linelen > fields->errmsglen) {
+		if (linelen > fields->errmsglen)
+		{
 		    /* linelen + null terminator */
 		    if ((fields->errmsg = vim_realloc(fields->errmsg,
 				    linelen + 1)) == NULL)
@@ -931,7 +933,8 @@ restofline:
 		if (regmatch.startp[i] == NULL || regmatch.endp[i] == NULL)
 		    continue;
 		len = (int)(regmatch.endp[i] - regmatch.startp[i]);
-		if (len > fields->errmsglen) {
+		if (len > fields->errmsglen)
+		{
 		    /* len + null terminator */
 		    if ((fields->errmsg = vim_realloc(fields->errmsg, len + 1))
 			    == NULL)
@@ -1013,7 +1016,8 @@ restofline:
 	fields->namebuf[0] = NUL;	/* no match found, remove file name */
 	fields->lnum = 0;			/* don't jump to this line */
 	fields->valid = FALSE;
-	if (linelen > fields->errmsglen) {
+	if (linelen > fields->errmsglen)
+	{
 	    /* linelen + null terminator */
 	    if ((fields->errmsg = vim_realloc(fields->errmsg,
 			    linelen + 1)) == NULL)
@@ -4798,7 +4802,8 @@ qf_add_entries(
 	qi->qf_lists[qi->qf_curlist].qf_nonevalid = TRUE;
     else
 	qi->qf_lists[qi->qf_curlist].qf_nonevalid = FALSE;
-    if (action != 'a') {
+    if (action != 'a')
+    {
 	qi->qf_lists[qi->qf_curlist].qf_ptr =
 	    qi->qf_lists[qi->qf_curlist].qf_start;
 	if (qi->qf_lists[qi->qf_curlist].qf_count > 0)
@@ -4861,6 +4866,18 @@ qf_set_properties(qf_info_T *qi, dict_T *what, int action)
     return retval;
 }
 
+    static void
+qf_free_stack(win_T *wp, qf_info_T *qi)
+{
+    qf_free_all(wp);
+    if (wp == NULL)
+    {
+	/* quickfix list */
+	qi->qf_curlist = 0;
+	qi->qf_listcount = 0;
+    }
+}
+
 /*
  * Populate the quickfix list with the items supplied in the list
  * of dictionaries. "title" will be copied to w:quickfix_title.
@@ -4884,7 +4901,12 @@ set_errorlist(
 	    return FAIL;
     }
 
-    if (what != NULL)
+    if (action == 'f')
+    {
+	/* Free the entire quickfix or location list stack */
+	qf_free_stack(wp, qi);
+    }
+    else if (what != NULL)
 	retval = qf_set_properties(qi, what, action);
     else
 	retval = qf_add_entries(qi, list, title, action);
@@ -5187,7 +5209,8 @@ ex_helpgrep(exarg_T *eap)
 			    /* Convert a line if 'encoding' is not utf-8 and
 			     * the line contains a non-ASCII character. */
 			    if (vc.vc_type != CONV_NONE
-						   && has_non_ascii(IObuff)) {
+						   && has_non_ascii(IObuff))
+			    {
 				line = string_convert(&vc, IObuff, NULL);
 				if (line == NULL)
 				    line = IObuff;

src/testdir/test_quickfix.vim

@@ -38,6 +38,7 @@ func s:setup_commands(cchar)
     command! -nargs=* Xhelpgrep helpgrep <args>
     let g:Xgetlist = function('getqflist')
     let g:Xsetlist = function('setqflist')
+    call setqflist([], 'f')
   else
     command! -nargs=* -bang Xlist <mods>llist<bang> <args>
     command! -nargs=* Xgetexpr <mods>lgetexpr <args>
@@ -69,6 +70,7 @@ func s:setup_commands(cchar)
     command! -nargs=* Xhelpgrep lhelpgrep <args>
     let g:Xgetlist = function('getloclist', [0])
     let g:Xsetlist = function('setloclist', [0])
+    call setloclist(0, [], 'f')
   endif
 endfunc
 
@@ -76,6 +78,9 @@ endfunc
 func XlistTests(cchar)
   call s:setup_commands(a:cchar)
 
+  if a:cchar == 'l'
+      call assert_fails('llist', 'E776:')
+  endif
   " With an empty list, command should return error
   Xgetexpr []
   silent! Xlist
@@ -146,6 +151,9 @@ endfunc
 func XageTests(cchar)
   call s:setup_commands(a:cchar)
 
+  let list = [{'bufnr': 1, 'lnum': 1}]
+  call g:Xsetlist(list)
+
   " Jumping to a non existent list should return error
   silent! Xolder 99
   call assert_true(v:errmsg ==# 'E380: At bottom of quickfix stack')
@@ -179,11 +187,7 @@ func XageTests(cchar)
 endfunc
 
 func Test_cage()
-  let list = [{'bufnr': 1, 'lnum': 1}]
-  call setqflist(list)
   call XageTests('c')
-
-  call setloclist(0, list)
   call XageTests('l')
 endfunc
 
@@ -192,6 +196,11 @@ endfunc
 func XwindowTests(cchar)
   call s:setup_commands(a:cchar)
 
+  " Opening the location list window without any errors should fail
+  if a:cchar == 'l'
+      call assert_fails('lopen', 'E776:')
+  endif
+
   " Create a list with no valid entries
   Xgetexpr ['non-error 1', 'non-error 2', 'non-error 3']
 
@@ -232,6 +241,19 @@ func XwindowTests(cchar)
   " Calling cwindow should close the quickfix window with no valid errors
   Xwindow
   call assert_true(winnr('$') == 1)
+
+  if a:cchar == 'c'
+      " Opening the quickfix window in multiple tab pages should reuse the
+      " quickfix buffer
+      Xgetexpr ['Xtestfile1:1:3:Line1', 'Xtestfile2:2:2:Line2',
+		  \ 'Xtestfile3:3:1:Line3']
+      Xopen
+      let qfbufnum = bufnr('%')
+      tabnew
+      Xopen
+      call assert_equal(qfbufnum, bufnr('%'))
+      new | only | tabonly
+  endif
 endfunc
 
 func Test_cwindow()
@@ -360,6 +382,13 @@ endfunc
 func Xtest_browse(cchar)
   call s:setup_commands(a:cchar)
 
+  " Jumping to first or next location list entry without any error should
+  " result in failure
+  if a:cchar == 'l'
+      call assert_fails('lfirst', 'E776:')
+      call assert_fails('lnext', 'E776:')
+  endif
+
   call s:create_test_file('Xqftestfile1')
   call s:create_test_file('Xqftestfile2')
 
@@ -1550,6 +1579,11 @@ endfunc
 func XbottomTests(cchar)
   call s:setup_commands(a:cchar)
 
+  " Calling lbottom without any errors should fail
+  if a:cchar == 'l'
+      call assert_fails('lbottom', 'E776:')
+  endif
+
   call g:Xsetlist([{'filename': 'foo', 'lnum': 42}]) 
   Xopen
   let wid = win_getid()
@@ -1571,10 +1605,9 @@ endfunc
 func HistoryTest(cchar)
   call s:setup_commands(a:cchar)
 
-  call assert_fails(a:cchar . 'older 99', 'E380:')
   " clear all lists after the first one, then replace the first one.
   call g:Xsetlist([])
-  Xolder
+  call assert_fails('Xolder 99', 'E380:')
   let entry = {'filename': 'foo', 'lnum': 42}
   call g:Xsetlist([entry], 'r')
   call g:Xsetlist([entry, entry])
@@ -1617,6 +1650,7 @@ func Xproperty_tests(cchar)
     call assert_fails('call g:Xsetlist([], "a", [])', 'E715:')
 
     " Set and get the title
+    call g:Xsetlist([])
     Xopen
     wincmd p
     call g:Xsetlist([{'filename':'foo', 'lnum':27}])

src/version.c

@@ -764,6 +764,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    517,
 /**/
     516,
 /**/