patch 8.0.1592: terminal windows in a session are not properly restored

Problem:    Terminal windows in a session are not properly restored.
Solution:   Add "terminal" in 'sessionoptions'.  When possible restore the
            command running in a terminal.

src/channel.c

@@ -4777,6 +4777,13 @@ get_job_options(typval_T *tv, jobopt_T *opt, int supported, int supported2)
 		opt->jo_set |= JO2_HIDDEN;
 		opt->jo_hidden = get_tv_number(item);
 	    }
+	    else if (STRCMP(hi->hi_key, "norestore") == 0)
+	    {
+		if (!(supported2 & JO2_NORESTORE))
+		    break;
+		opt->jo_set |= JO2_NORESTORE;
+		opt->jo_term_norestore = get_tv_number(item);
+	    }
 #endif
 	    else if (STRCMP(hi->hi_key, "env") == 0)
 	    {
@@ -5470,6 +5477,7 @@ job_start(typval_T *argvars, jobopt_T *opt_arg)
 	    goto theend;
 	}
 #ifdef USE_ARGV
+	/* This will modify "cmd". */
 	if (mch_parse_cmd(cmd, FALSE, &argv, &argc) == FAIL)
 	    goto theend;
 	argv[argc] = NULL;

src/evalfunc.c

@@ -867,6 +867,7 @@ static struct fst
     {"term_list",	0, 0, f_term_list},
     {"term_scrape",	2, 2, f_term_scrape},
     {"term_sendkeys",	2, 2, f_term_sendkeys},
+    {"term_setrestore",	2, 2, f_term_setrestore},
     {"term_start",	1, 2, f_term_start},
     {"term_wait",	1, 2, f_term_wait},
 #endif

src/ex_docmd.c

@@ -11095,6 +11095,11 @@ makeopens(
     {
 	if (!(only_save_windows && buf->b_nwindows == 0)
 		&& !(buf->b_help && !(ssop_flags & SSOP_HELP))
+#ifdef FEAT_TERMINAL
+		/* skip terminal buffers: finished ones are not useful, others
+		 * will be resurrected and result in a new buffer */
+		&& !bt_terminal(buf)
+#endif
 		&& buf->b_fname != NULL
 		&& buf->b_p_bl)
 	{
@@ -11305,7 +11310,8 @@ makeopens(
     /*
      * Wipe out an empty unnamed buffer we started in.
      */
-    if (put_line(fd, "if exists('s:wipebuf')") == FAIL)
+    if (put_line(fd, "if exists('s:wipebuf') && s:wipebuf != bufnr('%')")
+								       == FAIL)
 	return FAIL;
     if (put_line(fd, "  silent exe 'bwipe ' . s:wipebuf") == FAIL)
 	return FAIL;
@@ -11465,6 +11471,12 @@ ses_do_frame(frame_T *fr)
     static int
 ses_do_win(win_T *wp)
 {
+#ifdef FEAT_TERMINAL
+    if (bt_terminal(wp->w_buffer))
+	return !term_is_finished(wp->w_buffer)
+	    && (ssop_flags & SSOP_TERMINAL)
+	    && term_should_restore(wp->w_buffer);
+#endif
     if (wp->w_buffer->b_fname == NULL
 #ifdef FEAT_QUICKFIX
 	    /* When 'buftype' is "nofile" can't restore the window contents. */
@@ -11530,13 +11542,21 @@ put_view(
     /* Edit the file.  Skip this when ":next" already did it. */
     if (add_edit && (!did_next || wp->w_arg_idx_invalid))
     {
+# ifdef FEAT_TERMINAL
+	if (bt_terminal(wp->w_buffer))
+	{
+	    if (term_write_session(fd, wp) == FAIL)
+		return FAIL;
+	}
+	else
+# endif
 	/*
 	 * Load the file.
 	 */
 	if (wp->w_buffer->b_ffname != NULL
-#ifdef FEAT_QUICKFIX
+# ifdef FEAT_QUICKFIX
 		&& !bt_nofile(wp->w_buffer)
-#endif
+# endif
 		)
 	{
 	    /*
@@ -11554,8 +11574,7 @@ put_view(
 		    || fputs(" | else | edit ", fd) < 0
 		    || ses_fname(fd, wp->w_buffer, flagp, FALSE) == FAIL
 		    || fputs(" | endif", fd) < 0
-		    ||
-		put_eol(fd) == FAIL)
+		    || put_eol(fd) == FAIL)
 		return FAIL;
 	}
 	else

src/option.c

@@ -2403,7 +2403,7 @@ static struct vimoption options[] =
     {"sessionoptions", "ssop", P_STRING|P_VI_DEF|P_ONECOMMA|P_NODUP,
 #ifdef FEAT_SESSION
 			    (char_u *)&p_ssop, PV_NONE,
-	 {(char_u *)"blank,buffers,curdir,folds,help,options,tabpages,winsize",
+	 {(char_u *)"blank,buffers,curdir,folds,help,options,tabpages,winsize,terminal",
 							       (char_u *)0L}
 #else
 			    (char_u *)NULL, PV_NONE,

src/option.h

@@ -751,7 +751,7 @@ EXTERN unsigned	ssop_flags;
 /* Also used for 'viewoptions'! */
 static char *(p_ssop_values[]) = {"buffers", "winpos", "resize", "winsize",
     "localoptions", "options", "help", "blank", "globals", "slash", "unix",
-    "sesdir", "curdir", "folds", "cursor", "tabpages", NULL};
+    "sesdir", "curdir", "folds", "cursor", "tabpages", "terminal", NULL};
 # endif
 # define SSOP_BUFFERS		0x001
 # define SSOP_WINPOS		0x002
@@ -769,6 +769,7 @@ static char *(p_ssop_values[]) = {"buffers", "winpos", "resize", "winsize",
 # define SSOP_FOLDS		0x2000
 # define SSOP_CURSOR		0x4000
 # define SSOP_TABPAGES		0x8000
+# define SSOP_TERMINAL		0x10000
 #endif
 EXTERN char_u	*p_sh;		/* 'shell' */
 EXTERN char_u	*p_shcf;	/* 'shellcmdflag' */

src/proto/terminal.pro

@@ -1,5 +1,8 @@
 /* terminal.c */
 void ex_terminal(exarg_T *eap);
+int term_write_session(FILE *fd, win_T *wp);
+int term_should_restore(buf_T *buf);
+void f_term_setrestore(typval_T *argvars, typval_T *rettv);
 void free_terminal(buf_T *buf);
 void write_to_term(buf_T *buffer, char_u *msg, channel_T *channel);
 int term_job_running(term_T *term);

src/structs.h

@@ -1706,7 +1706,8 @@ struct channel_S {
 #define JO2_HIDDEN	    0x0400	/* "hidden" */
 #define JO2_TERM_OPENCMD    0x0800	/* "term_opencmd" */
 #define JO2_EOF_CHARS	    0x1000	/* "eof_chars" */
-#define JO2_ALL		    0x1FFF
+#define JO2_NORESTORE	    0x2000	/* "norestore" */
+#define JO2_ALL		    0x2FFF
 
 #define JO_MODE_ALL	(JO_MODE + JO_IN_MODE + JO_OUT_MODE + JO_ERR_MODE)
 #define JO_CB_ALL \
@@ -1769,6 +1770,7 @@ typedef struct
     int		jo_vertical;
     int		jo_curwin;
     int		jo_hidden;
+    int		jo_term_norestore;
     char_u	*jo_term_name;
     char_u	*jo_term_opencmd;
     int		jo_term_finish;

src/terminal.c

@@ -38,11 +38,10 @@
  * in tl_scrollback are no longer used.
  *
  * TODO:
- * - What to store in a session file?  Shell at the prompt would be OK to
- *   restore, but others may not.  Open the window and let the user start the
- *   command?  Also see #2650.
- * - Adding WinBar to terminal window doesn't display, text isn't shifted down.
+ * - Add a flag to kill the job when Vim is exiting.  Useful when it's showing
+ *   a logfile.  Or send keys there to make it quit: "exit\r" for a shell.
  * - When using 'termguicolors' still use the 16 ANSI colors as-is.  Helps for
+ * - Adding WinBar to terminal window doesn't display, text isn't shifted down.
  *   a job that uses 16 colors while Vim is using > 256.
  * - in GUI vertical split causes problems.  Cursor is flickering. (Hirohito
  *   Higashi, 2017 Sep 19)
@@ -135,6 +134,9 @@ struct terminal_S {
     void	*tl_winpty_config;
     void	*tl_winpty;
 #endif
+#if defined(FEAT_SESSION)
+    char_u	*tl_command;
+#endif
 
     /* last known vterm size */
     int		tl_rows;
@@ -487,6 +489,52 @@ term_start(typval_T *argvar, jobopt_T *opt, int without_job, int forceit)
     if (without_job)
 	return curbuf;
 
+#if defined(FEAT_SESSION)
+    /* Remember the command for the session file. */
+    if (opt->jo_term_norestore)
+    {
+	term->tl_command = vim_strsave((char_u *)"NONE");
+    }
+    else if (argvar->v_type == VAR_STRING)
+    {
+	char_u	*cmd = argvar->vval.v_string;
+
+	if (cmd != NULL && STRCMP(cmd, p_sh) != 0)
+	    term->tl_command = vim_strsave(cmd);
+    }
+    else if (argvar->v_type == VAR_LIST
+	    && argvar->vval.v_list != NULL
+	    && argvar->vval.v_list->lv_len > 0)
+    {
+	garray_T	ga;
+	listitem_T	*item;
+
+	ga_init2(&ga, 1, 100);
+	for (item = argvar->vval.v_list->lv_first;
+					item != NULL; item = item->li_next)
+	{
+	    char_u *s = get_tv_string_chk(&item->li_tv);
+	    char_u *p;
+
+	    if (s == NULL)
+		break;
+	    p = vim_strsave_fnameescape(s, FALSE);
+	    if (p == NULL)
+		break;
+	    ga_concat(&ga, p);
+	    vim_free(p);
+	    ga_append(&ga, ' ');
+	}
+	if (item == NULL)
+	{
+	    ga_append(&ga, NUL);
+	    term->tl_command = ga.ga_data;
+	}
+	else
+	    ga_clear(&ga);
+    }
+#endif
+
     /* System dependent: setup the vterm and maybe start the job in it. */
     if (argvar->v_type == VAR_STRING
 	    && argvar->vval.v_string != NULL
@@ -561,6 +609,8 @@ ex_terminal(exarg_T *eap)
 	    opt.jo_curwin = 1;
 	else if ((int)(p - cmd) == 6 && STRNICMP(cmd, "hidden", 6) == 0)
 	    opt.jo_hidden = 1;
+	else if ((int)(p - cmd) == 9 && STRNICMP(cmd, "norestore", 9) == 0)
+	    opt.jo_term_norestore = 1;
 	else if ((int)(p - cmd) == 4 && STRNICMP(cmd, "rows", 4) == 0
 		&& ep != NULL && isdigit(ep[1]))
 	{
@@ -620,6 +670,42 @@ ex_terminal(exarg_T *eap)
     vim_free(opt.jo_eof_chars);
 }
 
+#if defined(FEAT_SESSION) || defined(PROTO)
+/*
+ * Write a :terminal command to the session file to restore the terminal in
+ * window "wp".
+ * Return FAIL if writing fails.
+ */
+    int
+term_write_session(FILE *fd, win_T *wp)
+{
+    term_T *term = wp->w_buffer->b_term;
+
+    /* Create the terminal and run the command.  This is not without
+     * risk, but let's assume the user only creates a session when this
+     * will be OK. */
+    if (fprintf(fd, "terminal ++curwin ++cols=%d ++rows=%d ",
+		term->tl_cols, term->tl_rows) < 0)
+	return FAIL;
+    if (term->tl_command != NULL && fputs((char *)term->tl_command, fd) < 0)
+	return FAIL;
+
+    return put_eol(fd);
+}
+
+/*
+ * Return TRUE if "buf" has a terminal that should be restored.
+ */
+    int
+term_should_restore(buf_T *buf)
+{
+    term_T	*term = buf->b_term;
+
+    return term != NULL && (term->tl_command == NULL
+				     || STRCMP(term->tl_command, "NONE") != 0);
+}
+#endif
+
 /*
  * Free the scrollback buffer for "term".
  */
@@ -669,6 +755,9 @@ free_terminal(buf_T *buf)
 
     term_free_vterm(term);
     vim_free(term->tl_title);
+#ifdef FEAT_SESSION
+    vim_free(term->tl_command);
+#endif
     vim_free(term->tl_status_text);
     vim_free(term->tl_opencmd);
     vim_free(term->tl_eof_chars);
@@ -4047,6 +4136,29 @@ f_term_sendkeys(typval_T *argvars, typval_T *rettv)
     }
 }
 
+/*
+ * "term_setrestore(buf, command)" function
+ */
+    void
+f_term_setrestore(typval_T *argvars UNUSED, typval_T *rettv UNUSED)
+{
+#if defined(FEAT_SESSION)
+    buf_T	*buf = term_get_buf(argvars);
+    term_T	*term;
+    char_u	*cmd;
+
+    if (buf == NULL)
+	return;
+    term = buf->b_term;
+    vim_free(term->tl_command);
+    cmd = get_tv_string_chk(&argvars[1]);
+    if (cmd != NULL)
+	term->tl_command = vim_strsave(cmd);
+    else
+	term->tl_command = NULL;
+#endif
+}
+
 /*
  * "term_start(command, options)" function
  */
@@ -4064,7 +4176,8 @@ f_term_start(typval_T *argvars, typval_T *rettv)
 		    + JO_EXIT_CB + JO_CLOSE_CALLBACK + JO_OUT_IO,
 		JO2_TERM_NAME + JO2_TERM_FINISH + JO2_HIDDEN + JO2_TERM_OPENCMD
 		    + JO2_TERM_COLS + JO2_TERM_ROWS + JO2_VERTICAL + JO2_CURWIN
-		    + JO2_CWD + JO2_ENV + JO2_EOF_CHARS) == FAIL)
+		    + JO2_CWD + JO2_ENV + JO2_EOF_CHARS
+		    + JO2_NORESTORE) == FAIL)
 	return;
 
     if (opt.jo_vertical)
@@ -4566,6 +4679,7 @@ term_and_job_init(
 {
     create_vterm(term, term->tl_rows, term->tl_cols);
 
+    /* This will change a string in "argvar". */
     term->tl_job = job_start(argvar, opt);
     if (term->tl_job != NULL)
 	++term->tl_job->jv_refcount;

src/testdir/shared.vim

@@ -270,3 +270,10 @@ func! Screenline(lnum)
   let line = join(chars, '')
   return matchstr(line, '^.\{-}\ze\s*$')
 endfunc
+
+" Stops the shell running in terminal "buf".
+func Stop_shell_in_terminal(buf)
+  call term_sendkeys(a:buf, "exit\r")
+  let job = term_getjob(a:buf)
+  call WaitFor({-> job_status(job) == "dead"})
+endfunc