patch 9.1.0046: :drop does not re-use empty buffer

Problem:  :drop does not re-use empty buffer
          (Rocco Mao)
Solution: Make :drop re-use an empty buffer
          (Rocco Mao)

fixes: #13851
closes: #13881

Signed-off-by: Rocco Mao <dapeng.mao@qq.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/arglist.c

@@ -502,7 +502,7 @@ do_arglist(
     void
 set_arglist(char_u *str)
 {
-    do_arglist(str, AL_SET, 0, FALSE);
+    do_arglist(str, AL_SET, 0, TRUE);
 }
 
 /*

src/ex_cmds.c

@@ -5425,8 +5425,7 @@ ex_smile(exarg_T *eap UNUSED)
 
 /*
  * ":drop"
- * Opens the first argument in a window.  When there are two or more arguments
- * the argument list is redefined.
+ * Opens the first argument in a window, and the argument list is redefined.
  */
     void
 ex_drop(exarg_T *eap)
@@ -5463,6 +5462,8 @@ ex_drop(exarg_T *eap)
 	// edited in a window yet.  It's like ":tab all" but without closing
 	// windows or tabs.
 	ex_all(eap);
+	cmdmod.cmod_tab = 0;
+	ex_rewind(eap);
 	return;
     }
 
@@ -5486,6 +5487,7 @@ ex_drop(exarg_T *eap)
 		buf_check_timestamp(curbuf, FALSE);
 		curbuf->b_p_ar = save_ar;
 	    }
+	    ex_rewind(eap);
 	    return;
 	}
     }

src/testdir/test_excmd.vim

@@ -84,18 +84,27 @@ endfunc
 " Test for the :drop command
 func Test_drop_cmd()
   call writefile(['L1', 'L2'], 'Xdropfile', 'D')
+  " Test for reusing the current buffer
   enew | only
+  let expected_nr = bufnr()
   drop Xdropfile
+  call assert_equal(expected_nr, bufnr())
   call assert_equal('L2', getline(2))
   " Test for switching to an existing window
   below new
   drop Xdropfile
   call assert_equal(1, winnr())
-  " Test for splitting the current window
+  " Test for splitting the current window (set nohidden)
   enew | only
   set modified
   drop Xdropfile
   call assert_equal(2, winnr('$'))
+  " Not splitting the current window even if modified (set hidden)
+  set hidden
+  enew | only
+  set modified
+  drop Xdropfile
+  call assert_equal(1, winnr('$'))
   " Check for setting the argument list
   call assert_equal(['Xdropfile'], argv())
   enew | only!

src/testdir/test_tabpage.vim

@@ -164,6 +164,74 @@ func Test_tabpage_drop()
   bwipe!
   bwipe!
   call assert_equal(1, tabpagenr('$'))
+
+  call assert_equal(1, winnr('$'))
+  call assert_equal('', bufname(''))
+  call writefile(['L1', 'L2'], 'Xdropfile', 'D')
+
+  " Test for ':tab drop single-file': reuse current buffer
+  let expected_nr = bufnr()
+  tab drop Xdropfile
+  call assert_equal(1, tabpagenr('$'))
+  call assert_equal(expected_nr, bufnr())
+  call assert_equal('L2', getline(2))
+  bwipe!
+
+  " Test for ':tab drop single-file': not reuse modified buffer
+  set modified
+  let expected_nr = bufnr() + 1
+  tab drop Xdropfile
+  call assert_equal(2, tabpagenr())
+  call assert_equal(2, tabpagenr('$'))
+  call assert_equal(expected_nr, bufnr())
+  call assert_equal('L2', getline(2))
+  bwipe!
+
+  " Test for ':tab drop single-file': multiple tabs already exist
+  tab split f2
+  tab split f3
+  let expected_nr = bufnr() + 1
+  tab drop Xdropfile
+  call assert_equal(4, tabpagenr())
+  call assert_equal(4, tabpagenr('$'))
+  call assert_equal(expected_nr, bufnr())
+  call assert_equal('L2', getline(2))
+  %bwipe!
+
+  " Test for ':tab drop multi-files': reuse current buffer
+  let expected_nr = bufnr()
+  tab drop Xdropfile f1 f2 f3
+  call assert_equal(1, tabpagenr())
+  call assert_equal(4, tabpagenr('$'))
+  call assert_equal(expected_nr, bufnr())
+  call assert_equal('L2', getline(2))
+  %bwipe!
+
+  " Test for ':tab drop multi-files': not reuse modified buffer
+  set modified
+  let expected_nr = bufnr() + 1
+  tab drop Xdropfile f1 f2 f3
+  call assert_equal(2, tabpagenr())
+  call assert_equal(5, tabpagenr('$'))
+  call assert_equal(expected_nr, bufnr())
+  call assert_equal('L2', getline(2))
+  %bwipe!
+
+  " Test for ':tab drop multi-files': multiple tabs already exist
+  tab split f2
+  tab split f3
+  let expected_nr = bufnr() + 1
+  tab drop a b c
+  call assert_equal(4, tabpagenr())
+  call assert_equal(6, tabpagenr('$'))
+  call assert_equal(expected_nr, bufnr())
+  let expected_nr = bufnr() + 3
+  tab drop Xdropfile f1 f2 f3
+  call assert_equal(5, tabpagenr())
+  call assert_equal(8, tabpagenr('$'))
+  call assert_equal(expected_nr, bufnr())
+  call assert_equal('L2', getline(2))
+  %bwipe!
 endfunc
 
 " Test autocommands
@@ -260,14 +328,14 @@ function Test_tabpage_with_autocmd_tab_drop()
 
   let s:li = []
   tab drop test1
-  call assert_equal(['BufLeave', 'BufEnter'], s:li)
+  call assert_equal(['BufEnter'], s:li)
 
   let s:li = []
   tab drop test2 test3
   call assert_equal([
         \ 'TabLeave', 'TabEnter', 'TabLeave', 'TabEnter',
         \ 'TabLeave', 'WinEnter', 'TabEnter', 'BufEnter',
-        \ 'TabLeave', 'WinEnter', 'TabEnter', 'BufEnter'], s:li)
+        \ 'TabLeave', 'WinEnter', 'TabEnter', 'BufEnter', 'BufEnter'], s:li)
 
   autocmd! TestTabpageGroup
   augroup! TestTabpageGroup

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    46,
 /**/
     45,
 /**/