vim-patch:8.1.1015: quickfix buffer shows up in list, can't get buffer number

Problem:    Quickfix buffer shows up in list, can't get buffer number.
Solution:   Make the quickfix buffer unlisted when the quickfix window is
            closed.  get the quickfix buffer number with getqflist().
            (Yegappan Lakshmanan, closes vim/vim#4113)
https://github.com/vim/vim/commit/647e24ba3dbf7ff448aa471b1a659a18267ae056

5 files changed, 75 insertions, 23 deletions

diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index 5dbb24276f..201bb07cd2 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -3170,7 +3170,7 @@ complete_info([{what}])
 <
 						*confirm()*
 confirm({msg} [, {choices} [, {default} [, {type}]]])
-		Confirm() offers the user a dialog, from which a choice can be
+		confirm() offers the user a dialog, from which a choice can be
 		made.  It returns the number of the choice.  For the first
 		choice this is 1.
 
@@ -4639,10 +4639,16 @@ getloclist({nr},[, {what}])				*getloclist()*
 		If the optional {what} dictionary argument is supplied, then
 		returns the items listed in {what} as a dictionary. Refer to
 		|getqflist()| for the supported items in {what}.
-		If {what} contains 'filewinid', then returns the id of the
-		window used to display files from the location list. This
-		field is applicable only when called from a location list
-		window. See |location-list-file-window| for more details.
+
+		In addition to the items supported by |getqflist()| in {what},
+		the following item is supported by |getloclist()|:
+
+			filewinid 	id of the window used to display files
+					from the location list. This field is
+					applicable only when called from a
+					location list window. See
+					|location-list-file-window| for more
+					details.
 
 getmatches([{win}])					*getmatches()*
 		Returns a |List| with all matches previously defined for the
@@ -4744,6 +4750,9 @@ getqflist([{what}])					*getqflist()*
 			nr	get information for this quickfix list; zero
 				means the current quickfix list and "$" means
 				the last quickfix list
+			qfbufnr number of the buffer displayed in the quickfix
+				window. Returns 0 if the quickfix buffer is
+				not present. See |quickfix-buffer|.
 			size	number of entries in the quickfix list
 			title	get the list title |quickfix-title|
 			winid	get the quickfix |window-ID|
@@ -4772,6 +4781,8 @@ getqflist([{what}])					*getqflist()*
 			items	quickfix list entries. If not present, set to
 				an empty list.
 			nr	quickfix list number. If not present, set to 0
+			qfbufnr	number of the buffer displayed in the quickfix
+				window. If not present, set to 0.
 			size	number of entries in the quickfix list. If not
 				present, set to 0.
 			title	quickfix list title text. If not present, set
@@ -10378,14 +10389,14 @@ text...
 			commands are skipped.
 			When {pattern} is omitted all errors are caught.
 			Examples: >
-		:catch /^Vim:Interrupt$/	" catch interrupts (CTRL-C)
-		:catch /^Vim\%((\a\+)\)\=:E/	" catch all Vim errors
-		:catch /^Vim\%((\a\+)\)\=:/	" catch errors and interrupts
-		:catch /^Vim(write):/		" catch all errors in :write
-		:catch /^Vim\%((\a\+)\)\=:E123/	" catch error E123
-		:catch /my-exception/		" catch user exception
-		:catch /.*/			" catch everything
-		:catch				" same as /.*/
+		:catch /^Vim:Interrupt$/	 " catch interrupts (CTRL-C)
+		:catch /^Vim\%((\a\+)\)\=:E/	 " catch all Vim errors
+		:catch /^Vim\%((\a\+)\)\=:/	 " catch errors and interrupts
+		:catch /^Vim(write):/		 " catch all errors in :write
+		:catch /^Vim\%((\a\+)\)\=:E123:/ " catch error E123
+		:catch /my-exception/		 " catch user exception
+		:catch /.*/			 " catch everything
+		:catch				 " same as /.*/
 <
 			Another character can be used instead of / around the
 			{pattern}, so long as it does not have a special
diff --git a/runtime/doc/quickfix.txt b/runtime/doc/quickfix.txt
index 9da11a553d..7fe75d83c8 100644
--- a/runtime/doc/quickfix.txt
+++ b/runtime/doc/quickfix.txt
@@ -540,6 +540,7 @@ location list.
 			second quickfix window.  If [height] is given the
 			existing window will be resized to it.
 
+							*quickfix-buffer*
 			The window will contain a special buffer, with
 			'buftype' equal to "quickfix".  Don't change this!
 			The window will have the w:quickfix_title variable set
@@ -548,7 +549,11 @@ location list.
 			status line if the value of 'statusline' is adjusted
 			properly. Whenever this buffer is modified by a
 			quickfix command or function, the |b:changedtick|
-			variable is incremented.
+			variable is incremented.  You can get the number of
+			this buffer using the getqflist() and getloclist()
+			functions by passing the 'qfbufnr' item. For a
+			location list, this buffer is wiped out when the
+			location list is removed.
 
 							*:lop* *:lopen*
 :lop[en] [height]	Open a window to show the location list for the
@@ -714,12 +719,18 @@ using these functions are below:
     " get the quickfix list window id
     :echo getqflist({'winid' : 0}).winid
 
+    " get the quickfix list window buffer number
+    :echo getqflist({'qfbufnr' : 0}).qfbufnr
+
     " get the context of the current location list
     :echo getloclist(0, {'context' : 0}).context
 
     " get the location list window id of the third window
     :echo getloclist(3, {'winid' : 0}).winid
 
+    " get the location list window buffer number of the third window
+    :echo getloclist(3, {'qfbufnr' : 0}).qfbufnr
+
     " get the file window id of a location list window (winnr: 4)
     :echo getloclist(4, {'filewinid' : 0}).filewinid
 <
diff --git a/src/nvim/quickfix.c b/src/nvim/quickfix.c
index 06fed9c2cf..713cace259 100644
--- a/src/nvim/quickfix.c
+++ b/src/nvim/quickfix.c
@@ -5577,7 +5577,8 @@ enum {
   QF_GETLIST_SIZE = 0x80,
   QF_GETLIST_TICK = 0x100,
   QF_GETLIST_FILEWINID = 0x200,
-  QF_GETLIST_ALL = 0x3FF,
+  QF_GETLIST_QFBUFNR = 0x400,
+  QF_GETLIST_ALL = 0x7FF,
 };
 
 /// Parse text from 'di' and return the quickfix list items.
@@ -5632,6 +5633,15 @@ static int qf_winid(qf_info_T *qi)
   return 0;
 }
 
+// Returns the number of the buffer displayed in the quickfix/location list
+// window. If there is no buffer associated with the list, then returns 0.
+static int qf_getprop_qfbufnr(const qf_info_T *qi, dict_T *retdict)
+  FUNC_ATTR_NONNULL_ARG(2)
+{
+  return tv_dict_add_nr(retdict, S_LEN("qfbufnr"),
+                        (qi == NULL) ? 0 : qi->qf_bufnr);
+}
+
 /// Convert the keys in 'what' to quickfix list property flags.
 static int qf_getprop_keys2flags(const dict_T *what, bool loclist)
   FUNC_ATTR_NONNULL_ALL FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT
@@ -5675,6 +5685,9 @@ static int qf_getprop_keys2flags(const dict_T *what, bool loclist)
   if (loclist && tv_dict_find(what, S_LEN("filewinid")) != NULL) {
     flags |= QF_GETLIST_FILEWINID;
   }
+  if (tv_dict_find(what, S_LEN("qfbufnr")) != NULL) {
+    flags |= QF_GETLIST_QFBUFNR;
+  }
 
   return flags;
 }
@@ -5766,6 +5779,9 @@ static int qf_getprop_defaults(qf_info_T *qi,
   if ((status == OK) && locstack && (flags & QF_GETLIST_FILEWINID)) {
     status = tv_dict_add_nr(retdict, S_LEN("filewinid"), 0);
   }
+  if ((status == OK) && (flags & QF_GETLIST_QFBUFNR)) {
+    status = qf_getprop_qfbufnr(qi, retdict);
+  }
 
   return status;
 }
@@ -5900,6 +5916,9 @@ int qf_get_properties(win_T *wp, dict_T *what, dict_T *retdict)
   if ((status == OK) && (wp != NULL) && (flags & QF_GETLIST_FILEWINID)) {
     status = qf_getprop_filewinid(wp, qi, retdict);
   }
+  if ((status == OK) && (flags & QF_GETLIST_QFBUFNR)) {
+    status = qf_getprop_qfbufnr(qi, retdict);
+  }
 
   return status;
 }
diff --git a/src/nvim/testdir/test_quickfix.vim b/src/nvim/testdir/test_quickfix.vim
index dc1b20ce65..a8dd383e8c 100644
--- a/src/nvim/testdir/test_quickfix.vim
+++ b/src/nvim/testdir/test_quickfix.vim
@@ -3217,19 +3217,21 @@ func Xgetlist_empty_tests(cchar)
   call assert_equal(0, g:Xgetlist({'changedtick' : 0}).changedtick)
   if a:cchar == 'c'
     call assert_equal({'context' : '', 'id' : 0, 'idx' : 0,
-		  \ 'items' : [], 'nr' : 0, 'size' : 0,
+		  \ 'items' : [], 'nr' : 0, 'size' : 0, 'qfbufnr' : 0,
 		  \ 'title' : '', 'winid' : 0, 'changedtick': 0},
 		  \ g:Xgetlist({'all' : 0}))
   else
     call assert_equal({'context' : '', 'id' : 0, 'idx' : 0,
 		\ 'items' : [], 'nr' : 0, 'size' : 0, 'title' : '',
-		\ 'winid' : 0, 'changedtick': 0, 'filewinid' : 0},
+		\ 'winid' : 0, 'changedtick': 0, 'filewinid' : 0,
+		\ 'qfbufnr' : 0},
 		\ g:Xgetlist({'all' : 0}))
   endif
 
   " Quickfix window with empty stack
   silent! Xopen
   let qfwinid = (a:cchar == 'c') ? win_getid() : 0
+  let qfbufnr = (a:cchar == 'c') ? bufnr('') : 0
   call assert_equal(qfwinid, g:Xgetlist({'winid' : 0}).winid)
   Xclose
 
@@ -3261,11 +3263,12 @@ func Xgetlist_empty_tests(cchar)
   if a:cchar == 'c'
     call assert_equal({'context' : '', 'id' : 0, 'idx' : 0, 'items' : [],
 		\ 'nr' : 0, 'size' : 0, 'title' : '', 'winid' : 0,
+		\ 'qfbufnr' : qfbufnr,
 		\ 'changedtick' : 0}, g:Xgetlist({'id' : qfid, 'all' : 0}))
   else
     call assert_equal({'context' : '', 'id' : 0, 'idx' : 0, 'items' : [],
 		\ 'nr' : 0, 'size' : 0, 'title' : '', 'winid' : 0,
-		\ 'changedtick' : 0, 'filewinid' : 0},
+		\ 'changedtick' : 0, 'filewinid' : 0, 'qfbufnr' : 0},
 		\ g:Xgetlist({'id' : qfid, 'all' : 0}))
   endif
 
@@ -3282,11 +3285,12 @@ func Xgetlist_empty_tests(cchar)
   if a:cchar == 'c'
     call assert_equal({'context' : '', 'id' : 0, 'idx' : 0, 'items' : [],
 		\ 'nr' : 0, 'size' : 0, 'title' : '', 'winid' : 0,
-		\ 'changedtick' : 0}, g:Xgetlist({'nr' : 5, 'all' : 0}))
+		\ 'changedtick' : 0, 'qfbufnr' : qfbufnr},
+		\ g:Xgetlist({'nr' : 5, 'all' : 0}))
   else
     call assert_equal({'context' : '', 'id' : 0, 'idx' : 0, 'items' : [],
 		\ 'nr' : 0, 'size' : 0, 'title' : '', 'winid' : 0,
-		\ 'changedtick' : 0, 'filewinid' : 0},
+		\ 'changedtick' : 0, 'filewinid' : 0, 'qfbufnr' : 0},
 		\ g:Xgetlist({'nr' : 5, 'all' : 0}))
   endif
 endfunc
@@ -4040,6 +4044,7 @@ func Xqfbuf_test(cchar)
   Xclose
   " Even after the quickfix window is closed, the buffer should be loaded
   call assert_true(bufloaded(qfbnum))
+  call assert_true(qfbnum, g:Xgetlist({'qfbufnr' : 0}).qfbufnr)
   Xopen
   " Buffer should be reused when opening the window again
   call assert_equal(qfbnum, bufnr(''))
@@ -4058,7 +4063,7 @@ func Xqfbuf_test(cchar)
     close
     " When the location list window is closed, the buffer name should not
     " change to 'Quickfix List'
-    call assert_match(qfbnum . '  h-  "\[Location List]"', execute('ls'))
+    call assert_match(qfbnum . 'u h-  "\[Location List]"', execute('ls!'))
     call assert_true(bufloaded(qfbnum))
 
     " After deleting a location list buffer using ":bdelete", opening the
@@ -4075,6 +4080,7 @@ func Xqfbuf_test(cchar)
     " removed
     call setloclist(0, [], 'f')
     call assert_false(bufexists(qfbnum))
+    call assert_equal(0, getloclist(0, {'qfbufnr' : 0}).qfbufnr)
 
     " When the location list is freed with the location list window open, the
     " location list buffer should not be lost. It should be reused when the
diff --git a/src/nvim/window.c b/src/nvim/window.c
index e53570edd8..7d08336c25 100644
--- a/src/nvim/window.c
+++ b/src/nvim/window.c
@@ -2578,9 +2578,14 @@ int win_close(win_T *win, bool free_buf)
     return OK;
   }
 
-  /* Free independent synblock before the buffer is freed. */
-  if (win->w_buffer != NULL)
+  // Free independent synblock before the buffer is freed.
+  if (win->w_buffer != NULL) {
     reset_synblock(win);
+  }
+  // When the quickfix/location list window is closed, unlist the buffer.
+  if (win->w_buffer != NULL && bt_quickfix(win->w_buffer)) {
+    win->w_buffer->b_p_bl = false;
+  }
 
   /*
    * Close the link to the buffer.