patch 8.2.1959: crash when terminal buffer name is made empty

Problem:    Crash when terminal buffer name is made empty. (Dhiraj Mishra)
Solution:   Fall back to "[No Name]". (closes #7262)

src/buffer.c

@@ -5648,10 +5648,21 @@ buf_spname(buf_T *buf)
     }
 
     if (buf->b_fname == NULL)
-	return (char_u *)_("[No Name]");
+	return buf_get_fname(buf);
     return NULL;
 }
 
+/*
+ * Get "buf->b_fname", use "[No Name]" if it is NULL.
+ */
+    char_u *
+buf_get_fname(buf_T *buf)
+{
+    if (buf->b_fname == NULL)
+	return (char_u *)_("[No Name]");
+    return buf->b_fname;
+}
+
 /*
  * Set 'buflisted' for curbuf to "on" and trigger autocommands if it changed.
  */

src/proto/buffer.pro

@@ -66,6 +66,7 @@ int bt_dontwrite(buf_T *buf);
 int bt_dontwrite_msg(buf_T *buf);
 int buf_hide(buf_T *buf);
 char_u *buf_spname(buf_T *buf);
+char_u *buf_get_fname(buf_T *buf);
 void set_buflisted(int on);
 int buf_contents_changed(buf_T *buf);
 void wipe_buffer(buf_T *buf, int aucmd);

src/terminal.c

@@ -1598,7 +1598,7 @@ term_try_stop_job(buf_T *buf)
 	char_u	buff[DIALOG_MSG_SIZE];
 	int	ret;
 
-	dialog_msg(buff, _("Kill job in \"%s\"?"), buf->b_fname);
+	dialog_msg(buff, _("Kill job in \"%s\"?"), buf_get_fname(buf));
 	ret = vim_dialog_yesnocancel(VIM_QUESTION, NULL, buff, 1);
 	if (ret == VIM_YES)
 	    how = "kill";
@@ -4517,6 +4517,7 @@ term_get_status_text(term_T *term)
     {
 	char_u *txt;
 	size_t len;
+	char_u *fname;
 
 	if (term->tl_normal_mode)
 	{
@@ -4533,11 +4534,12 @@ term_get_status_text(term_T *term)
 	    txt = (char_u *)_("running");
 	else
 	    txt = (char_u *)_("finished");
-	len = 9 + STRLEN(term->tl_buffer->b_fname) + STRLEN(txt);
+	fname = buf_get_fname(term->tl_buffer);
+	len = 9 + STRLEN(fname) + STRLEN(txt);
 	term->tl_status_text = alloc(len);
 	if (term->tl_status_text != NULL)
 	    vim_snprintf((char *)term->tl_status_text, len, "%s [%s]",
-						term->tl_buffer->b_fname, txt);
+								   fname, txt);
     }
     return term->tl_status_text;
 }

src/testdir/test_terminal.vim

@@ -41,6 +41,16 @@ func Test_terminal_basic()
   unlet g:job
 endfunc
 
+func Test_terminal_no_name()
+  let buf = Run_shell_in_terminal({})
+  call assert_match('^!', bufname(buf))
+  0file
+  call assert_equal("", bufname(buf))
+  call assert_match('\[No Name\]', execute('file'))
+  call StopShellInTerminal(buf)
+  call TermWait(buf)
+endfunc
+
 func Test_terminal_TerminalWinOpen()
   au TerminalWinOpen * let b:done = 'yes'
   let buf = Run_shell_in_terminal({})

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1959,
 /**/
     1958,
 /**/