From: Yuan Fu <casouri@gmail.com>
Date: Sat, 1 Jun 2024 17:20:48 +0000 (-0700)
Subject: Check for buffer liveness when accessing tree-sitter node (bug#71012)
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=2336a4a8019ade0e4ab00ed1ae8b6f70552ce009;p=emacs.git

Check for buffer liveness when accessing tree-sitter node (bug#71012)

* src/treesit.h (treesit_node_buffer_live_p): Declare function.
* src/print.c (print_vectorlike): Print node without position if
buffer is killed.
* src/treesit.c (treesit_node_buffer_live_p): New function.
(treesit_check_node): Add buffer liveness check.
(syms_of_treesit): New error treesit-node-buffer-killed.

(cherry picked from commit 20af58d3a13ddb5c2ca376da8cdd3fde4833ca2d)
---

diff --git a/src/print.c b/src/print.c
index 7aacd2b2e90..6a27ceac5f0 100644
--- a/src/print.c
+++ b/src/print.c
@@ -2033,6 +2033,11 @@ print_vectorlike_unreadable (Lisp_Object obj, Lisp_Object printcharfun,
 	  print_c_string ("-outdated>", printcharfun);
 	  return;
 	}
+      if (!treesit_node_buffer_live_p (obj))
+	{
+	  print_c_string ("-in-killed-buffer>", printcharfun);
+	  break;
+	}
       printchar (' ', printcharfun);
       /* Now the node must be up-to-date, and calling functions like
 	 Ftreesit_node_start will not signal.  */
diff --git a/src/treesit.c b/src/treesit.c
index d86ab501187..9f0eb061056 100644
--- a/src/treesit.c
+++ b/src/treesit.c
@@ -1837,6 +1837,13 @@ treesit_check_node (Lisp_Object obj)
   CHECK_TS_NODE (obj);
   if (!treesit_node_uptodate_p (obj))
     xsignal1 (Qtreesit_node_outdated, obj);
+
+  /* Technically a lot of node functions can work without the
+     associated buffer being alive, but I doubt there're any real
+     use-cases for that; OTOH putting the buffer-liveness check here is
+     simple, clean, and safe.  */
+  if (!treesit_node_buffer_live_p (obj))
+    xsignal1 (Qtreesit_node_buffer_killed, obj);
 }
 
 /* Checks that OBJ is a positive integer and it is within the visible
@@ -1857,6 +1864,14 @@ treesit_node_uptodate_p (Lisp_Object obj)
   return XTS_NODE (obj)->timestamp == XTS_PARSER (lisp_parser)->timestamp;
 }
 
+bool
+treesit_node_buffer_live_p (Lisp_Object obj)
+{
+  struct buffer *buffer
+    = XBUFFER (XTS_PARSER (XTS_NODE (obj)->parser)->buffer);
+  return BUFFER_LIVE_P (buffer);
+}
+
 DEFUN ("treesit-node-type",
        Ftreesit_node_type, Streesit_node_type, 1, 1, 0,
        doc: /* Return the NODE's type as a string.
@@ -4016,6 +4031,8 @@ syms_of_treesit (void)
 	  "treesit-load-language-error");
   DEFSYM (Qtreesit_node_outdated,
 	  "treesit-node-outdated");
+  DEFSYM (Qtreesit_node_buffer_killed,
+	  "treesit-node-buffer-killed");
   DEFSYM (Quser_emacs_directory,
 	  "user-emacs-directory");
   DEFSYM (Qtreesit_parser_deleted, "treesit-parser-deleted");
@@ -4046,6 +4063,9 @@ syms_of_treesit (void)
   define_error (Qtreesit_node_outdated,
 		"This node is outdated, please retrieve a new one",
 		Qtreesit_error);
+  define_error (Qtreesit_node_buffer_killed,
+		"The buffer associated with this node is killed",
+		Qtreesit_error);
   define_error (Qtreesit_parser_deleted,
 		"This parser is deleted and cannot be used",
 		Qtreesit_error);
diff --git a/src/treesit.h b/src/treesit.h
index bb81bf0e2b3..d3c6aa4c250 100644
--- a/src/treesit.h
+++ b/src/treesit.h
@@ -194,6 +194,7 @@ extern Lisp_Object make_treesit_parser (Lisp_Object, TSParser *, TSTree *,
 extern Lisp_Object make_treesit_node (Lisp_Object, TSNode);
 
 extern bool treesit_node_uptodate_p (Lisp_Object);
+extern bool treesit_node_buffer_live_p (Lisp_Object);
 
 extern void treesit_delete_parser (struct Lisp_TS_Parser *);
 extern void treesit_delete_query (struct Lisp_TS_Query *);