vim-patch:8.0.1023: it is not easy to identify a quickfix list

Problem:    It is not easy to identify a quickfix list.
Solution:   Add the "id" field. (Yegappan Lakshmanan)
a539f4f1ae

runtime/doc/eval.txt

@@ -4335,6 +4335,9 @@ getqflist([{what}])					*getqflist()*
 		returns only the items listed in {what} as a dictionary. The
 		following string items are supported in {what}:
 			context	get the context stored with |setqflist()|
+			id	get information for the quickfix list with
+				|quickfix-ID|; zero means the id for the
+				current list or the list specifed by 'nr'
 			items	quickfix list entries
 			nr	get information for this quickfix list; zero
 				means the current quickfix list and '$' means
@@ -4349,6 +4352,8 @@ getqflist([{what}])					*getqflist()*
 			all	all of the above quickfix properties
 		Non-string items in {what} are ignored.
 		If "nr" is not present then the current quickfix list is used.
+		If both "nr" and a non-zero "id" are specified, then the list
+		specified by "id" is used.
 		To get the number of lists in the quickfix stack, set 'nr' to
 		'$' in {what}. The 'nr' value in the returned dictionary
 		contains the quickfix stack size.
@@ -4360,6 +4365,7 @@ getqflist([{what}])					*getqflist()*
 
 		The returned dictionary contains the following entries:
 			context	context information stored with |setqflist()|
+			id	quickfix list ID |quickfix-ID|
 			items	quickfix list entries
 			nr	quickfix list number
 			title	quickfix list title text
@@ -6926,6 +6932,7 @@ setqflist({list} [, {action}[, {what}]])		*setqflist()*
 				text and add the resulting entries to the
 				quickfix list {nr}.  The value can be a string
 				with one line or a list with multiple lines.
+		    id		quickfix list identifier |quickfix-ID|
 		    items	list of quickfix entries. Same as the {list}
 				argument.
 		    nr		list number in the quickfix stack; zero
@@ -6936,6 +6943,9 @@ setqflist({list} [, {action}[, {what}]])		*setqflist()*
 		If the "nr" item is not present, then the current quickfix list
 		is modified. When creating a new quickfix list, "nr" can be
 		set to a value one greater than the quickfix stack size.
+		When modifying a quickfix list, to guarantee that the correct
+		list is modified, 'id' should be used instead of 'nr' to
+		specify the list.
 
 		Examples: >
 			:call setqflist([], 'r', {'title': 'My search'})

src/nvim/quickfix.c

@@ -82,6 +82,7 @@ struct qfline_S {
 /// created using setqflist()/setloclist() with a title and/or user context
 /// information and entries can be added later using setqflist()/setloclist().
 typedef struct qf_list_S {
+  unsigned qf_id;               ///< Unique identifier for this list
   qfline_T    *qf_start;        ///< pointer to the first error
   qfline_T    *qf_last;         ///< pointer to the last error
   qfline_T    *qf_ptr;          ///< pointer to the current error
@@ -117,6 +118,7 @@ struct qf_info_S {
 };
 
 static qf_info_T ql_info;       /* global quickfix list */
+static unsigned last_qf_id = 0;   // Last Used quickfix list id
 
 #define FMT_PATTERNS 10         /* maximum number of % recognized */
 
@@ -1224,6 +1226,7 @@ static void qf_new_list(qf_info_T *qi, char_u *qf_title)
     qi->qf_curlist = qi->qf_listcount++;
   memset(&qi->qf_lists[qi->qf_curlist], 0, (size_t)(sizeof(qf_list_T)));
   qf_store_title(qi, qi->qf_curlist, qf_title);
+  qi->qf_lists[qi->qf_curlist].qf_id = ++last_qf_id;
 }
 
 /*
@@ -1467,6 +1470,9 @@ void copy_loclist(win_T *from, win_T *to)
 
     to_qfl->qf_index = from_qfl->qf_index;      /* current index in the list */
 
+    // Assign a new ID for the location list
+    to_qfl->qf_id = ++last_qf_id;
+
     /* When no valid entries are present in the list, qf_ptr points to
      * the first item in the list */
     if (to_qfl->qf_nonevalid) {
@@ -2458,6 +2464,7 @@ static void qf_free(qf_info_T *qi, int idx)
   qfl->qf_title = NULL;
   tv_free(qfl->qf_ctx);
   qfl->qf_ctx = NULL;
+  qfl->qf_id = 0;
 }
 
 /*
@@ -4110,6 +4117,7 @@ enum {
   QF_GETLIST_NR = 0x4,
   QF_GETLIST_WINID = 0x8,
   QF_GETLIST_CONTEXT = 0x10,
+  QF_GETLIST_ID = 0x20,
   QF_GETLIST_ALL = 0xFF
 };
 
@@ -4155,16 +4163,17 @@ int get_errorlist_properties(win_T *wp, dict_T *what, dict_T *retdict)
 
   if (wp != NULL) {
     qi = GET_LOC_LIST(wp);
-    if (qi == NULL) {
+  }
-      // If querying for the size of the location list, return 0
+  // List is not present or is empty
+  if (qi == NULL || qi->qf_listcount == 0) {
+    // If querying for the size of the list, return 0
     if (((di = tv_dict_find(what, S_LEN("nr"))) != NULL)
         && (di->di_tv.v_type == VAR_STRING)
-          && strequal((const char *)di->di_tv.vval.v_string, "$")) {
+        && (STRCMP(di->di_tv.vval.v_string, "$") == 0)) {
       return tv_dict_add_nr(retdict, S_LEN("nr"), 0);
     }
     return FAIL;
   }
-  }
 
   int status = OK;
   int flags = QF_GETLIST_NONE;
@@ -4179,45 +4188,52 @@ int get_errorlist_properties(win_T *wp, dict_T *what, dict_T *retdict)
         if (qf_idx < 0 || qf_idx >= qi->qf_listcount) {
           return FAIL;
         }
-      } else if (qi->qf_listcount == 0) {  // stack is empty
-        return FAIL;
       }
-      flags |= QF_GETLIST_NR;
     } else if (di->di_tv.v_type == VAR_STRING
                && strequal((const char *)di->di_tv.vval.v_string, "$")) {
       // Get the last quickfix list number
-      if (qi->qf_listcount > 0) {
       qf_idx = qi->qf_listcount - 1;
     } else {
-        qf_idx = -1;  // Quickfix stack is empty
+      return FAIL;
     }
     flags |= QF_GETLIST_NR;
+  }
+
+  if ((di = tv_dict_find(what, S_LEN("id"))) != NULL) {
+    // Look for a list with the specified id
+    if (di->di_tv.v_type == VAR_NUMBER) {
+      // For zero, use the current list or the list specifed by 'nr'
+      if (di->di_tv.vval.v_number != 0) {
+        for (qf_idx = 0; qf_idx < qi->qf_listcount; qf_idx++) {
+          if (qi->qf_lists[qf_idx].qf_id == di->di_tv.vval.v_number) {
+            break;
+          }
+        }
+        if (qf_idx == qi->qf_listcount) {
+          return FAIL;      // List not found
+        }
+      }
+      flags |= QF_GETLIST_ID;
     } else {
       return FAIL;
     }
   }
 
-  if (qf_idx != -1) {
   if (tv_dict_find(what, S_LEN("all")) != NULL) {
     flags |= QF_GETLIST_ALL;
   }
-
   if (tv_dict_find(what, S_LEN("title")) != NULL) {
     flags |= QF_GETLIST_TITLE;
   }
-
   if (tv_dict_find(what, S_LEN("winid")) != NULL) {
     flags |= QF_GETLIST_WINID;
   }
-
   if (tv_dict_find(what, S_LEN("context")) != NULL) {
     flags |= QF_GETLIST_CONTEXT;
   }
-
   if (tv_dict_find(what, S_LEN("items")) != NULL) {
     flags |= QF_GETLIST_ITEMS;
   }
-  }
 
   if (flags & QF_GETLIST_TITLE) {
     char_u *t = qi->qf_lists[qf_idx].qf_title;
@@ -4254,6 +4270,10 @@ int get_errorlist_properties(win_T *wp, dict_T *what, dict_T *retdict)
     }
   }
 
+  if ((status == OK) && (flags & QF_GETLIST_ID)) {
+    status = tv_dict_add_nr(retdict, S_LEN("id"), qi->qf_lists[qf_idx].qf_id);
+  }
+
   return status;
 }
 
@@ -4410,6 +4430,22 @@ static int qf_set_properties(qf_info_T *qi, dict_T *what, int action,
     }
   }
 
+  if (!newlist && (di = tv_dict_find(what, S_LEN("id"))) != NULL) {
+    // Use the quickfix/location list with the specified id
+    if (di->di_tv.v_type == VAR_NUMBER) {
+      for (qf_idx = 0; qf_idx < qi->qf_listcount; qf_idx++) {
+        if (qi->qf_lists[qf_idx].qf_id == di->di_tv.vval.v_number) {
+          break;
+        }
+      }
+      if (qf_idx == qi->qf_listcount) {
+        return FAIL;      // List not found
+      }
+    } else {
+      return FAIL;
+    }
+  }
+
   if (newlist) {
     qi->qf_curlist = qf_idx;
     qf_new_list(qi, title);

src/nvim/testdir/test_quickfix.vim

@@ -1879,8 +1879,9 @@ func Xproperty_tests(cchar)
     call g:Xsetlist([], 'r', {'nr':2,'title':'Fruits','context':['Fruits']})
     let l1=g:Xgetlist({'nr':1,'all':1})
     let l2=g:Xgetlist({'nr':2,'all':1})
-    let l1.nr=2
+    let save_id = l1.id
-    let l2.nr=1
+    let l1.id=l2.id
+    let l2.id=save_id
     call g:Xsetlist([], 'r', l1)
     call g:Xsetlist([], 'r', l2)
     let newl1=g:Xgetlist({'nr':1,'all':1})
@@ -2527,3 +2528,38 @@ func Test_get_list_from_text()
   call XgetListFromText('c')
   call XgetListFromText('l')
 endfunc
+
+" Tests for the quickfix list id
+func Xqfid_tests(cchar)
+  call s:setup_commands(a:cchar)
+
+  call g:Xsetlist([], 'f')
+  call assert_equal({}, g:Xgetlist({'id':0}))
+  Xexpr ''
+  let start_id = g:Xgetlist({'id' : 0}).id
+  Xexpr '' | Xexpr ''
+  Xolder
+  call assert_equal(start_id, g:Xgetlist({'id':0, 'nr':1}).id)
+  call assert_equal(start_id + 1, g:Xgetlist({'id':0, 'nr':0}).id)
+  call assert_equal(start_id + 2, g:Xgetlist({'id':0, 'nr':'$'}).id)
+  call assert_equal({}, g:Xgetlist({'id':0, 'nr':99}))
+  call assert_equal(2, g:Xgetlist({'id':start_id + 1, 'nr':0}).nr)
+  call assert_equal({}, g:Xgetlist({'id':99, 'nr':0}))
+  call assert_equal({}, g:Xgetlist({'id':"abc", 'nr':0}))
+
+  call g:Xsetlist([], 'a', {'id':start_id, 'context':[1,2]})
+  call assert_equal([1,2], g:Xgetlist({'nr':1, 'context':1}).context)
+  call g:Xsetlist([], 'a', {'id':start_id+1, 'text':'F1:10:L10'})
+  call assert_equal('L10', g:Xgetlist({'nr':2, 'items':1}).items[0].text)
+  call assert_equal(-1, g:Xsetlist([], 'a', {'id':999, 'title':'Vim'}))
+  call assert_equal(-1, g:Xsetlist([], 'a', {'id':'abc', 'title':'Vim'}))
+
+  let qfid = g:Xgetlist({'id':0, 'nr':0})
+  call g:Xsetlist([], 'f')
+  call assert_equal({}, g:Xgetlist({'id':qfid, 'nr':0}))
+endfunc
+
+func Test_qf_id()
+  call Xqfid_tests('c')
+  call Xqfid_tests('l')
+endfunc