patch 8.0.0910: cannot create a terminal in the current window

Problem:    Cannot create a terminal in the current window.
Solution:   Add option "curwin" and ++curwin.

runtime/doc/eval.txt

@@ -8077,6 +8077,9 @@ term_start({cmd}, {options})				*term_start()*
 		   "term_cols"	     horizontal size to use for the terminal,
 		   		     instead of using 'termsize'
 		   "vertical"	     split the window vertically
+		   "curwin"	     use the current window, do not split the
+				     window; fails if the current buffer
+				     cannot be |abandon|ed
 		   "term_finish"     What to do when the job is finished:
 					"close": close any windows
 					"open": open window if needed

src/channel.c

@@ -4455,6 +4455,13 @@ get_job_options(typval_T *tv, jobopt_T *opt, int supported, int supported2)
 		opt->jo_set |= JO2_VERTICAL;
 		opt->jo_vertical = get_tv_number(item);
 	    }
+	    else if (STRCMP(hi->hi_key, "curwin") == 0)
+	    {
+		if (!(supported2 & JO2_CURWIN))
+		    break;
+		opt->jo_set |= JO2_CURWIN;
+		opt->jo_curwin = get_tv_number(item);
+	    }
 #endif
 	    else if (STRCMP(hi->hi_key, "env") == 0)
 	    {

src/ex_cmds.h

@@ -1484,7 +1484,7 @@ EX(CMD_tearoff,		"tearoff",	ex_tearoff,
 			NEEDARG|EXTRA|TRLBAR|NOTRLCOM|CMDWIN,
 			ADDR_LINES),
 EX(CMD_terminal,	"terminal",	ex_terminal,
-			RANGE|NOTADR|FILES|TRLBAR|CMDWIN,
+			RANGE|NOTADR|BANG|FILES|TRLBAR|CMDWIN,
 			ADDR_OTHER),
 EX(CMD_tfirst,		"tfirst",	ex_tag,
 			RANGE|NOTADR|BANG|TRLBAR|ZEROR,

src/structs.h

@@ -1691,7 +1691,8 @@ struct channel_S {
 #define JO2_TERM_ROWS	    0x0040	/* "term_rows" */
 #define JO2_TERM_COLS	    0x0080	/* "term_cols" */
 #define JO2_VERTICAL	    0x0100	/* "vertical" */
-#define JO2_ALL		    0x01FF
+#define JO2_CURWIN	    0x0200	/* "curwin" */
+#define JO2_ALL		    0x03FF
 
 #define JO_MODE_ALL	(JO_MODE + JO_IN_MODE + JO_OUT_MODE + JO_ERR_MODE)
 #define JO_CB_ALL \
@@ -1752,6 +1753,7 @@ typedef struct
     int		jo_term_rows;
     int		jo_term_cols;
     int		jo_vertical;
+    int		jo_curwin;
     char_u	*jo_term_name;
     int		jo_term_finish;
 #endif

src/terminal.c

@@ -244,7 +244,7 @@ setup_job_options(jobopt_T *opt, int rows, int cols)
 }
 
     static void
-term_start(char_u *cmd, jobopt_T *opt)
+term_start(char_u *cmd, jobopt_T *opt, int forceit)
 {
     exarg_T	split_ea;
     win_T	*old_curwin = curwin;
@@ -261,8 +261,22 @@ term_start(char_u *cmd, jobopt_T *opt)
     term->tl_finish = opt->jo_term_finish;
     ga_init2(&term->tl_scrollback, sizeof(sb_line_T), 300);
 
-    /* Open a new window or tab. */
     vim_memset(&split_ea, 0, sizeof(split_ea));
+    if (opt->jo_curwin)
+    {
+	/* Create a new buffer in the current window. */
+	if (!can_abandon(curbuf, forceit))
+	{
+	    EMSG(_(e_nowrtmsg));
+	    return;
+	}
+	if (do_ecmd(0, NULL, NULL, &split_ea, ECMD_ONE,
+		     ECMD_HIDE + (forceit ? ECMD_FORCEIT : 0), curwin) == FAIL)
+	    return;
+    }
+    else
+    {
+	/* Open a new window or tab. */
 	split_ea.cmdidx = CMD_new;
 	split_ea.cmd = (char_u *)"new";
 	split_ea.arg = (char_u *)"";
@@ -284,6 +298,7 @@ term_start(char_u *cmd, jobopt_T *opt)
 	    vim_free(term);
 	    return;
 	}
+    }
     term->tl_buffer = curbuf;
     curbuf->b_term = term;
 
@@ -378,6 +393,8 @@ ex_terminal(exarg_T *eap)
 	    opt.jo_term_finish = 'c';
 	else if ((int)(p - cmd) == 4 && STRNICMP(cmd, "open", 4) == 0)
 	    opt.jo_term_finish = 'o';
+	else if ((int)(p - cmd) == 6 && STRNICMP(cmd, "curwin", 6) == 0)
+	    opt.jo_curwin = 1;
 	else
 	{
 	    if (*p)
@@ -400,9 +417,8 @@ ex_terminal(exarg_T *eap)
 	else
 	    opt.jo_term_rows = eap->line2;
     }
-    /* TODO: get more options from before the command */
 
-    term_start(cmd, &opt);
+    term_start(cmd, &opt, eap->forceit);
 }
 
 /*
@@ -2365,13 +2381,13 @@ f_term_start(typval_T *argvars, typval_T *rettv)
 		JO_TIMEOUT_ALL + JO_STOPONEXIT
 		    + JO_EXIT_CB + JO_CLOSE_CALLBACK,
 		JO2_TERM_NAME + JO2_TERM_FINISH
-		    + JO2_TERM_COLS + JO2_TERM_ROWS + JO2_VERTICAL
+		    + JO2_TERM_COLS + JO2_TERM_ROWS + JO2_VERTICAL + JO2_CURWIN
 		    + JO2_CWD + JO2_ENV) == FAIL)
 	return;
 
     if (opt.jo_vertical)
 	cmdmod.split = WSP_VERT;
-    term_start(cmd, &opt);
+    term_start(cmd, &opt, FALSE);
 
     if (curbuf->b_term != NULL)
 	rettv->vval.v_number = curbuf->b_fnum;

src/testdir/test_terminal.vim

@@ -283,6 +283,38 @@ func Test_terminal_size()
   let size = term_getsize('')
   bwipe!
   call assert_equal([7, 27], size)
+endfunc
+
+func Test_terminal_curwin()
+  let cmd = Get_cat_123_cmd()
+  call assert_equal(1, winnr('$'))
+
+  split dummy
+  exe 'terminal ++curwin ' . cmd
+  call assert_equal(2, winnr('$'))
+  bwipe!
+
+  split dummy
+  call term_start(cmd, {'curwin': 1})
+  call assert_equal(2, winnr('$'))
+  bwipe!
+
+  split dummy
+  call setline(1, 'change')
+  call assert_fails('terminal ++curwin ' . cmd, 'E37:')
+  call assert_equal(2, winnr('$'))
+  exe 'terminal! ++curwin ' . cmd
+  call assert_equal(2, winnr('$'))
+  bwipe!
+
+  split dummy
+  call setline(1, 'change')
+  call assert_fails("call term_start(cmd, {'curwin': 1})", 'E37:')
+  call assert_equal(2, winnr('$'))
+  bwipe!
+
+  split dummy
+  bwipe!
 
 endfunc
 

src/version.c

@@ -769,6 +769,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    910,
 /**/
     909,
 /**/