patch 8.1.2312: "line:" field in tags file not used

Problem:    "line:" field in tags file not used.
Solution:   Recognize the field and use the value. (Andy Massimino, Daniel
            Hahler, closes #5232, closes #2546, closes #1057)

src/tag.c

@@ -35,6 +35,7 @@ typedef struct tag_pointers
     char_u	*tagkind_end;	// end of tagkind
     char_u	*user_data;	// user_data string
     char_u	*user_data_end;	// end of user_data
+    linenr_T	tagline;	// "line:" value
 } tagptrs_T;
 
 /*
@@ -3217,6 +3218,7 @@ parse_match(
 
     tagp->tagkind = NULL;
     tagp->user_data = NULL;
+    tagp->tagline = 0;
     tagp->command_end = NULL;
 
     if (retval == OK)
@@ -3237,6 +3239,8 @@ parse_match(
 			tagp->tagkind = p + 5;
 		    else if (STRNCMP(p, "user_data:", 10) == 0)
 			tagp->user_data = p + 10;
+		    else if (STRNCMP(p, "line:", 5) == 0)
+			tagp->tagline = atoi((char *)p + 5);
 		    if (tagp->tagkind != NULL && tagp->user_data != NULL)
 			break;
 		    pc = vim_strchr(p, ':');
@@ -3537,7 +3541,12 @@ jumpto_tag(
 	    p_ic = FALSE;	/* don't ignore case now */
 	    p_scs = FALSE;
 	    save_lnum = curwin->w_cursor.lnum;
-	    curwin->w_cursor.lnum = 0;	/* start search before first line */
+	    if (tagp.tagline > 0)
+		// start search before line from "line:" field
+		curwin->w_cursor.lnum = tagp.tagline - 1;
+	    else
+		// start search before first line
+		curwin->w_cursor.lnum = 0;
 	    if (do_search(NULL, pbuf[0], pbuf + 1, (long)1,
 							 search_options, NULL))
 		retval = OK;

src/testdir/test_tagjump.vim

@@ -526,4 +526,28 @@ func Test_tselect()
   call delete('XTest_tselect')
 endfunc
 
+func Test_tagline()
+  call writefile([
+	\ 'provision	Xtest.py	/^    def provision(self, **kwargs):$/;"	m	line:1	language:Python class:Foo',
+	\ 'provision	Xtest.py	/^    def provision(self, **kwargs):$/;"	m	line:3	language:Python class:Bar',
+	\], 'Xtags')
+  call writefile([
+	\ '    def provision(self, **kwargs):',
+	\ '        pass',
+	\ '    def provision(self, **kwargs):',
+	\ '        pass',
+	\], 'Xtest.py')
+
+  set tags=Xtags
+
+  1tag provision
+  call assert_equal(line('.'), 1)
+  2tag provision
+  call assert_equal(line('.'), 3)
+
+  call delete('Xtags')
+  call delete('Xtest.py')
+  set tags&
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab

src/version.c

@@ -741,6 +741,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2312,
 /**/
     2311,
 /**/