Merge from origin/emacs-26

7296b6f Improve cl-do, cl-do* docstrings
d416109 Avoid returning early in 'while-no-input' due to subprocesses
e8a4d94 Cleanup when opening a new terminal fails. (Bug#32794)

# Conflicts:
#	etc/NEWS

7 files changed, 61 insertions, 4 deletions

diff --git a/etc/NEWS.26 b/etc/NEWS.26
index 19dd433cda4..94bb45c6feb 100644
--- a/etc/NEWS.26
+++ b/etc/NEWS.26
@@ -110,6 +110,16 @@ be removed prior using the changed 'shadow-*' commands.
 The old name is an alias of the new name.  Future Emacs version will
 obsolete it.
 
+---
+** 'while-no-input' does not return due to input from subprocesses.
+Input that arrived from subprocesses while some code executed inside
+the 'while-no-input' form injected an internal buffer-switch event
+that counted as input and would cause 'while-no-input' to return,
+perhaps prematurely.  These buffer-switch events are now by default
+ignored by 'while-no-input'; if you need to get the old behavior,
+remove 'buffer-switch' from the list of events in
+'while-no-input-ignore-events'.
+
 
 * Lisp Changes in Emacs 26.2
 
diff --git a/lisp/emacs-lisp/cl-macs.el b/lisp/emacs-lisp/cl-macs.el
index d0d1c3b156a..29ddd491af0 100644
--- a/lisp/emacs-lisp/cl-macs.el
+++ b/lisp/emacs-lisp/cl-macs.el
@@ -1779,7 +1779,24 @@ such that COMBO is equivalent to (and . CLAUSES)."
 
 ;;;###autoload
 (defmacro cl-do (steps endtest &rest body)
-  "The Common Lisp `do' loop.
+  "Bind variables and run BODY forms until END-TEST returns non-nil.
+First, each VAR is bound to the associated INIT value as if by a `let' form.
+Then, in each iteration of the loop, the END-TEST is evaluated; if true,
+the loop is finished.  Otherwise, the BODY forms are evaluated, then each
+VAR is set to the associated STEP expression (as if by a `cl-psetq' form)
+and the next iteration begins.
+
+Once the END-TEST becomes true, the RESULT forms are evaluated (with
+the VARs still bound to their values) to produce the result
+returned by `cl-do'.
+
+Note that the entire loop is enclosed in an implicit `nil' block, so
+that you can use `cl-return' to exit at any time.
+
+Also note that END-TEST is checked before evaluating BODY.  If END-TEST
+is initially non-nil, `cl-do' will exit without running BODY.
+
+For more details, see `cl-do' description in Info node `(cl) Iteration'.
 
 \(fn ((VAR INIT [STEP])...) (END-TEST [RESULT...]) BODY...)"
   (declare (indent 2)
@@ -1791,7 +1808,25 @@ such that COMBO is equivalent to (and . CLAUSES)."
 
 ;;;###autoload
 (defmacro cl-do* (steps endtest &rest body)
-  "The Common Lisp `do*' loop.
+  "Bind variables and run BODY forms until END-TEST returns non-nil.
+First, each VAR is bound to the associated INIT value as if by a `let*' form.
+Then, in each iteration of the loop, the END-TEST is evaluated; if true,
+the loop is finished.  Otherwise, the BODY forms are evaluated, then each
+VAR is set to the associated STEP expression (as if by a `setq'
+form) and the next iteration begins.
+
+Once the END-TEST becomes true, the RESULT forms are evaluated (with
+the VARs still bound to their values) to produce the result
+returned by `cl-do*'.
+
+Note that the entire loop is enclosed in an implicit `nil' block, so
+that you can use `cl-return' to exit at any time.
+
+Also note that END-TEST is checked before evaluating BODY.  If END-TEST
+is initially non-nil, `cl-do*' will exit without running BODY.
+
+This is to `cl-do' what `let*' is to `let'.
+For more details, see `cl-do*' description in Info node `(cl) Iteration'.
 
 \(fn ((VAR INIT [STEP])...) (END-TEST [RESULT...]) BODY...)"
   (declare (indent 2) (debug cl-do))
diff --git a/lisp/subr.el b/lisp/subr.el
index 4c05111f516..41dc9aa45f5 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -3570,7 +3570,7 @@ is allowed once again.  (Immediately, if `inhibit-quit' is nil.)"
 ;; Don't throw `throw-on-input' on those events by default.
 (setq while-no-input-ignore-events
       '(focus-in focus-out help-echo iconify-frame
-        make-frame-visible selection-request))
+        make-frame-visible selection-request buffer-switch))
 
 (defmacro while-no-input (&rest body)
   "Execute BODY only as long as there's no pending input.
diff --git a/src/keyboard.c b/src/keyboard.c
index 1c1f1514ae8..35d74f4a795 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -3554,6 +3554,7 @@ kbd_buffer_store_buffered_event (union buffered_input_event *event,
     case ICONIFY_EVENT: ignore_event = Qiconify_frame; break;
     case DEICONIFY_EVENT: ignore_event = Qmake_frame_visible; break;
     case SELECTION_REQUEST_EVENT: ignore_event = Qselection_request; break;
+    case BUFFER_SWITCH_EVENT: ignore_event = Qbuffer_switch; break;
     default: ignore_event = Qnil; break;
     }
 
@@ -11082,6 +11083,8 @@ syms_of_keyboard (void)
   /* Menu and tool bar item parts.  */
   DEFSYM (Qmenu_enable, "menu-enable");
 
+  DEFSYM (Qbuffer_switch, "buffer-switch");
+
 #ifdef HAVE_NTGUI
   DEFSYM (Qlanguage_change, "language-change");
   DEFSYM (Qend_session, "end-session");
diff --git a/src/term.c b/src/term.c
index ce24f6915fc..852dc23bd60 100644
--- a/src/term.c
+++ b/src/term.c
@@ -4008,6 +4008,7 @@ init_tty (const char *name, const char *terminal_type, bool must_succeed)
         char const *diagnostic
           = (fd < 0) ? "Could not open file: %s" : "Not a tty device: %s";
         emacs_close (fd);
+        delete_terminal_internal (terminal);
         maybe_fatal (must_succeed, terminal, diagnostic, diagnostic, name);
       }
 
diff --git a/src/termhooks.h b/src/termhooks.h
index 211429169ba..4e341055100 100644
--- a/src/termhooks.h
+++ b/src/termhooks.h
@@ -733,6 +733,7 @@ extern struct terminal *get_named_terminal (const char *);
 extern struct terminal *create_terminal (enum output_method,
                                          struct redisplay_interface *);
 extern void delete_terminal (struct terminal *);
+extern void delete_terminal_internal (struct terminal *);
 extern Lisp_Object terminal_glyph_code (struct terminal *, int);
 
 /* The initial terminal device, created by initial_term_init.  */
diff --git a/src/terminal.c b/src/terminal.c
index 18982fe7044..e4803592575 100644
--- a/src/terminal.c
+++ b/src/terminal.c
@@ -314,7 +314,6 @@ create_terminal (enum output_method type, struct redisplay_interface *rif)
 void
 delete_terminal (struct terminal *terminal)
 {
-  struct terminal **tp;
   Lisp_Object tail, frame;
 
   /* Protect against recursive calls.  delete_frame calls the
@@ -335,6 +334,14 @@ delete_terminal (struct terminal *terminal)
         }
     }
 
+  delete_terminal_internal (terminal);
+}
+
+void
+delete_terminal_internal (struct terminal *terminal)
+{
+  struct terminal **tp;
+
   for (tp = &terminal_list; *tp != terminal; tp = &(*tp)->next_terminal)
     if (! *tp)
       emacs_abort ();