vim-patch:8.1.1466: not updating priority on existing sign

Problem:    Not updating priority on existing sign.
Solution:   Set the sign priority.  Add a test. (Yegappan Lakshmanan)
58a7f87c86

runtime/doc/eval.txt

@@ -7818,7 +7818,7 @@ sign_getplaced([{expr} [, {dict}]])			*sign_getplaced()*
 			priority	sign priority
 
 		The returned signs in a buffer are ordered by their line
-		number.
+		number and priority.
 
 		Returns an empty list on failure or if there are no placed
 		signs.

runtime/doc/sign.txt

@@ -176,9 +176,9 @@ See |sign_place()| for the equivalent Vim script function.
 
 		By default, the sign is assigned a default priority of 10. To
 		assign a different priority value, use "priority={prio}" to
-		specify a value. The priority is used to determine the
-		highlight group used when multiple signs are placed on the
-		same line.
+		specify a value.  The priority is used to determine the sign
+		that is displayed when multiple signs are placed on the same
+		line.
 
 		Examples: >
 			:sign place 5 line=3 name=sign1 file=a.py
@@ -198,7 +198,9 @@ See |sign_place()| for the equivalent Vim script function.
 		it (e.g., when the debugger has stopped at a breakpoint).
 
 		The optional "group={group}" attribute can be used before
-		"file=" to select a sign in a particular group.
+		"file=" to select a sign in a particular group.  The optional
+		"priority={prio}" attribute can be used to change the priority
+		of an existing sign.
 
 :sign place {id} name={name} [buffer={nr}]
 		Same, but use buffer {nr}.  If the buffer argument is not

src/nvim/sign.c

@@ -284,6 +284,7 @@ void buf_addsign(
         && sign_in_group(sign, groupname)) {
       // Update an existing sign
       sign->typenr = typenr;
+      sign->priority = prio;
       return;
     } else if (lnum < sign->lnum) {
       insert_sign_by_lnum_prio(buf, prev, id, groupname, prio, lnum, typenr);

src/nvim/testdir/test_signs.vim

@@ -1127,6 +1127,24 @@ func Test_sign_priority()
 	      \ 'priority' : 10}],
 	      \ s[0].signs)
 
+  " Place multiple signs with same id on a line with different priority
+  call sign_place(1, '', 'sign1', 'Xsign',
+	      \ {'lnum' : 5, 'priority' : 20})
+  call sign_place(1, '', 'sign2', 'Xsign',
+	      \ {'lnum' : 5, 'priority' : 10})
+  let s = sign_getplaced('Xsign', {'lnum' : 5})
+  call assert_equal([
+	      \ {'id' : 1, 'name' : 'sign2', 'lnum' : 5, 'group' : '',
+	      \ 'priority' : 10}],
+	      \ s[0].signs)
+  call sign_place(1, '', 'sign2', 'Xsign',
+	      \ {'lnum' : 5, 'priority' : 5})
+  let s = sign_getplaced('Xsign', {'lnum' : 5})
+  call assert_equal([
+	      \ {'id' : 1, 'name' : 'sign2', 'lnum' : 5, 'group' : '',
+	      \ 'priority' : 5}],
+	      \ s[0].signs)
+
   " Error case
   call assert_fails("call sign_place(1, 'g1', 'sign1', 'Xsign',
 	      \ [])", 'E715:')