From: Stefan Monnier <monnier@iro.umontreal.ca>
Date: Fri, 7 Oct 2022 23:15:07 +0000 (-0400)
Subject: itree: Try and detect non-local exits during itree iterations
X-Git-Tag: emacs-29.0.90~1616^2~406^2~29
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=208de5de59ae85887d637ec93690e17c418a7ab6;p=emacs.git

itree: Try and detect non-local exits during itree iterations

* src/itree.c (itree_busy_p): New function.
* src/eval.c (signal_or_quit): Use it.
* src/itree.h (itree_busy_p): Declare it.
---

diff --git a/src/eval.c b/src/eval.c
index 7da1d8fb989..37c25c79148 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -1711,6 +1711,7 @@ signal_or_quit (Lisp_Object error_symbol, Lisp_Object data, bool keyboard_quit)
   Lisp_Object clause = Qnil;
   struct handler *h;
 
+  eassert (!itree_busy_p ());
   if (gc_in_progress || waiting_for_input)
     emacs_abort ();
 
diff --git a/src/itree.c b/src/itree.c
index d955c575390..de16af5b0c2 100644
--- a/src/itree.c
+++ b/src/itree.c
@@ -725,6 +725,12 @@ interval_tree_validate (struct interval_tree *tree, struct interval_node *node)
   return node;
 }
 
+bool
+itree_busy_p (void)
+{
+  return (iter && iter->running);
+}
+
 /* Start a generator iterating all intervals in [BEGIN,END) in the
    given ORDER. Only one iterator per tree can be running at any
    time.
diff --git a/src/itree.h b/src/itree.h
index 9e40b87cc4f..7fdc9c07c93 100644
--- a/src/itree.h
+++ b/src/itree.h
@@ -129,6 +129,7 @@ void interval_tree_iter_finish (struct interval_generator *);
 struct interval_node *interval_generator_next (struct interval_generator *);
 void interval_tree_insert_gap (struct interval_tree *, ptrdiff_t, ptrdiff_t);
 void interval_tree_delete_gap (struct interval_tree *, ptrdiff_t, ptrdiff_t);
+bool itree_busy_p (void);
 
 /* Iterate over the intervals between BEG and END in the tree T.
    N will hold successive nodes.  ORDER can be one of : `ASCENDING`,
@@ -148,9 +149,7 @@ void interval_tree_delete_gap (struct interval_tree *, ptrdiff_t, ptrdiff_t);
      be able to run ELisp code (or GC for that matter).
    - If you need to exit the loop early, you *have* to call `ITREE_ABORT`
      just before exiting (e.g. with `break` or `return`).
-   - Non-local exits are not supported within the body of the loop,
-     unless the caller makes sure `ITREE_ABORT` is called via some
-     kind of unwind_protect.
+   - Non-local exits are not supported within the body of the loop.
    - Don't modify the tree during the iteration.
  */
 #define ITREE_FOREACH(n, t, beg, end, order)                        \