patch 7.4.1893

Problem:    Cannot easily get the window ID for a buffer.
Solution:   Add bufwinid().

runtime/doc/eval.txt

@@ -1862,6 +1862,7 @@ buflisted({expr})		Number	TRUE if buffer {expr} is listed
 bufloaded({expr})		Number	TRUE if buffer {expr} is loaded
 bufname({expr})			String	Name of the buffer {expr}
 bufnr({expr} [, {create}])	Number	Number of the buffer {expr}
+bufwinid({expr})		Number	window ID of buffer {expr}
 bufwinnr({expr})		Number	window number of buffer {expr}
 byte2line({byte})		Number	line number at byte count {byte}
 byteidx({expr}, {nr})		Number	byte index of {nr}'th char in {expr}
@@ -2557,6 +2558,16 @@ bufnr({expr} [, {create}])
 							*last_buffer_nr()*
 		Obsolete name for bufnr("$"): last_buffer_nr().
 
+bufwinid({expr})					*bufwinid()*
+		The result is a Number, which is the window ID of the first
+		window associated with buffer {expr}.  For the use of {expr},
+		see |bufname()| above.	If buffer {expr} doesn't exist or
+		there is no such window, -1 is returned.  Example: >
+
+	echo "A window containing buffer 1 is " . (bufwinid(1))
+<
+		Only deals with the current tab page.
+
 bufwinnr({expr})					*bufwinnr()*
 		The result is a Number, which is the number of the first
 		window associated with buffer {expr}.  For the use of {expr},

src/eval.c

@@ -500,6 +500,7 @@ static void f_buflisted(typval_T *argvars, typval_T *rettv);
 static void f_bufloaded(typval_T *argvars, typval_T *rettv);
 static void f_bufname(typval_T *argvars, typval_T *rettv);
 static void f_bufnr(typval_T *argvars, typval_T *rettv);
+static void f_bufwinid(typval_T *argvars, typval_T *rettv);
 static void f_bufwinnr(typval_T *argvars, typval_T *rettv);
 static void f_byte2line(typval_T *argvars, typval_T *rettv);
 static void byteidx(typval_T *argvars, typval_T *rettv, int comp);
@@ -8488,6 +8489,7 @@ static struct fst
     {"bufloaded",	1, 1, f_bufloaded},
     {"bufname",		1, 1, f_bufname},
     {"bufnr",		1, 2, f_bufnr},
+    {"bufwinid",	1, 1, f_bufwinid},
     {"bufwinnr",	1, 1, f_bufwinnr},
     {"byte2line",	1, 1, f_byte2line},
     {"byteidx",		2, 2, f_byteidx},
@@ -10213,11 +10215,8 @@ f_bufnr(typval_T *argvars, typval_T *rettv)
 	rettv->vval.v_number = -1;
 }
 
-/*
- * "bufwinnr(nr)" function
- */
     static void
-f_bufwinnr(typval_T *argvars, typval_T *rettv)
+buf_win_common(typval_T *argvars, typval_T *rettv, int get_nr)
 {
 #ifdef FEAT_WINDOWS
     win_T	*wp;
@@ -10235,13 +10234,32 @@ f_bufwinnr(typval_T *argvars, typval_T *rettv)
 	if (wp->w_buffer == buf)
 	    break;
     }
-    rettv->vval.v_number = (wp != NULL ? winnr : -1);
+    rettv->vval.v_number = (wp != NULL ? (get_nr ? winnr : wp->w_id) : -1);
 #else
-    rettv->vval.v_number = (curwin->w_buffer == buf ? 1 : -1);
+    rettv->vval.v_number = (curwin->w_buffer == buf
+					  ? (get_nr ? 1 : curwin->w_id) : -1);
 #endif
     --emsg_off;
 }
 
+/*
+ * "bufwinid(nr)" function
+ */
+    static void
+f_bufwinid(typval_T *argvars, typval_T *rettv)
+{
+    buf_win_common(argvars, rettv, FALSE);
+}
+
+/*
+ * "bufwinnr(nr)" function
+ */
+    static void
+f_bufwinnr(typval_T *argvars, typval_T *rettv)
+{
+    buf_win_common(argvars, rettv, TRUE);
+}
+
 /*
  * "byte2line(byte)" function
  */

src/version.c

@@ -753,6 +753,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1893,
 /**/
     1892,
 /**/