patch 9.0.1546: some commands for opening a file don't use 'switchbuf'

Problem:    Some commands for opening a file don't use 'switchbuf'.
Solution:   Use 'switchbuf' for more commands. (Yegappan Lakshmanan,
            closes #12383, closes #12381)

runtime/doc/options.txt

@@ -7928,16 +7928,18 @@ A jump table for the options with a short description can be found at |Q_op|.
 'switchbuf' 'swb'	string	(default "")
 			global
 	This option controls the behavior when switching between buffers.
-	Mostly for |quickfix| commands some values are also used for other
+	This option is checked, when
-	commands, as mentioned below.
+	- jumping to errors with the |quickfix| commands (|:cc|, |:cn|, |:cp|,
+	  etc.)
+	- jumping to a tag using the |:stag| command.
+	- opening a file using the |CTRL-W_f| or |CTRL-W_F| command.
+	- jumping to a buffer using a buffer split command (e.g.  |:sbuffer|,
+	  |:sbnext|, or |:sbrewind|).
 	Possible values (comma-separated list):
-	   useopen	If included, jump to the first open window that
+	   useopen	If included, jump to the first open window in the
-			contains the specified buffer (if there is one).
+			current tab page that contains the specified buffer
-			Otherwise: Do not examine other windows.
+			(if there is one).  Otherwise: Do not examine other
-			This setting is checked with |quickfix| commands, when
+			windows.
-			jumping to errors (":cc", ":cn", "cp", etc.).  It is
-			also used in all buffer related split commands, for
-			example ":sbuffer", ":sbnext", or ":sbrewind".
 	   usetab	Like "useopen", but also consider windows in other tab
 			pages.
 	   split	If included, split the current window before loading

src/buffer.c

@@ -2560,7 +2560,6 @@ buflist_getfpos(void)
     }
 }
 
-#if defined(FEAT_QUICKFIX) || defined(FEAT_EVAL) || defined(FEAT_SPELL) || defined(PROTO)
 /*
  * Find file in buffer list by name (it has to be for the current window).
  * Returns NULL if not found.
@@ -2586,7 +2585,6 @@ buflist_findname_exp(char_u *fname)
     }
     return buf;
 }
-#endif
 
 /*
  * Find file in buffer list by name (it has to be for the current window).

src/testdir/test_gf.vim

@@ -292,4 +292,65 @@ func Test_gf_subdirs_wildcard()
   set path&
 endfunc
 
+" Test for 'switchbuf' with gf and gF commands
+func Test_gf_switchbuf()
+  call writefile(repeat(["aaa"], 10), "Xtest1", 'D')
+  edit Xtest1
+  new
+  call setline(1, ['Xtest1'])
+
+  " Test for 'useopen'
+  set switchbuf=useopen
+  call cursor(1, 1)
+  exe "normal \<C-W>f"
+  call assert_equal([2, 2], [winnr(), winnr('$')])
+  close
+
+  " If the file is opened in another tabpage, then it should not be considered
+  tabedit Xtest1
+  tabfirst
+  exe "normal \<C-W>f"
+  call assert_equal([1, 2], [winnr(), winnr('$')])
+  call assert_equal([1, 2], [tabpagenr(), tabpagenr('$')])
+  close
+
+  " Test for 'usetab'
+  set switchbuf=usetab
+  exe "normal \<C-W>f"
+  call assert_equal([1, 1], [winnr(), winnr('$')])
+  call assert_equal([2, 2], [tabpagenr(), tabpagenr('$')])
+  %bw!
+
+  " Test for CTRL-W_F with 'useopen'
+  set isfname-=:
+  call setline(1, ['Xtest1:5'])
+  set switchbuf=useopen
+  split +1 Xtest1
+  wincmd b
+  exe "normal \<C-W>F"
+  call assert_equal([1, 2], [winnr(), winnr('$')])
+  call assert_equal(5, line('.'))
+  close
+
+  " If the file is opened in another tabpage, then it should not be considered
+  tabedit +1 Xtest1
+  tabfirst
+  exe "normal \<C-W>F"
+  call assert_equal([1, 2], [winnr(), winnr('$')])
+  call assert_equal(5, line('.'))
+  call assert_equal([1, 2], [tabpagenr(), tabpagenr('$')])
+  close
+
+  " Test for CTRL_W_F with 'usetab'
+  set switchbuf=usetab
+  exe "normal \<C-W>F"
+  call assert_equal([2, 2], [tabpagenr(), tabpagenr('$')])
+  call assert_equal([1, 1], [winnr(), winnr('$')])
+  call assert_equal(5, line('.'))
+
+  set switchbuf=
+  set isfname&
+  %bw!
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1546,
 /**/
     1545,
 /**/

src/window.c

@@ -580,7 +580,29 @@ wingotofile:
 		    need_mouse_correct = TRUE;
 #endif
 		    setpcmark();
-		    if (win_split(0, 0) == OK)
+
+		    // If 'switchbuf' is set to 'useopen' or 'usetab' and the
+		    // file is already opened in a window, then jump to it.
+		    wp = NULL;
+		    if ((swb_flags & (SWB_USEOPEN | SWB_USETAB))
+						&& cmdmod.cmod_tab == 0)
+		    {
+			buf_T *existing_buf = buflist_findname_exp(ptr);
+
+			if (existing_buf != NULL)
+			{
+			    if (swb_flags & SWB_USEOPEN)
+				wp = buf_jump_open_win(existing_buf);
+
+			    // If 'switchbuf' contains "usetab": jump to first
+			    // window in any tab page containing "existing_buf"
+			    // if one exists.
+			    if (wp == NULL && (swb_flags & SWB_USETAB))
+				wp = buf_jump_open_tab(existing_buf);
+			}
+		    }
+
+		    if (wp == NULL && win_split(0, 0) == OK)
 		    {
 			RESET_BINDING(curwin);
 			if (do_ecmd(0, ptr, NULL, NULL, ECMD_LASTL,
@@ -591,13 +613,16 @@ wingotofile:
 			    win_close(curwin, FALSE);
 			    goto_tabpage_win(oldtab, oldwin);
 			}
-			else if (nchar == 'F' && lnum >= 0)
+			else
+			    wp = curwin;
+		    }
+
+		    if (wp != NULL && nchar == 'F' && lnum >= 0)
 		    {
 			curwin->w_cursor.lnum = lnum;
 			check_cursor_lnum();
 			beginline(BL_SOL | BL_FIX);
 		    }
-		    }
 		    vim_free(ptr);
 		}
 		break;