From 6f580542c1796d3e7ba4d1dd40b2fe73fe00e5db Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Wed, 22 Jan 2020 23:43:29 -0800 Subject: [PATCH] Fix crash when sending Gnus message (Bug#39207) * src/alloc.c (resize_string_data): The string must be multibyte. When not bothering to reallocate, do bother to change the byte count. * test/src/alloc-tests.el (aset-nbytes-change) New test. --- src/alloc.c | 4 +++- test/src/alloc-tests.el | 7 +++++++ 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/src/alloc.c b/src/alloc.c index 99d5ca149d5..a35b48cfb22 100644 --- a/src/alloc.c +++ b/src/alloc.c @@ -1889,7 +1889,7 @@ allocate_string_data (struct Lisp_String *s, tally_consing (needed); } -/* Reallocate the data for STRING when a single character is replaced. +/* Reallocate multibyte STRING data when a single character is replaced. The character is at byte offset CIDX_BYTE in the string. The character being replaced is CLEN bytes long, and the character that will replace it is NEW_CLEN bytes long. @@ -1900,6 +1900,7 @@ unsigned char * resize_string_data (Lisp_Object string, ptrdiff_t cidx_byte, int clen, int new_clen) { + eassume (STRING_MULTIBYTE (string)); sdata *old_sdata = SDATA_OF_STRING (XSTRING (string)); ptrdiff_t nchars = SCHARS (string); ptrdiff_t nbytes = SBYTES (string); @@ -1911,6 +1912,7 @@ resize_string_data (Lisp_Object string, ptrdiff_t cidx_byte, { /* No need to reallocate, as the size change falls within the alignment slop. */ + XSTRING (string)->u.s.size_byte = new_nbytes; new_charaddr = data + cidx_byte; memmove (new_charaddr + new_clen, new_charaddr + clen, nbytes - (cidx_byte + (clen - 1))); diff --git a/test/src/alloc-tests.el b/test/src/alloc-tests.el index 4eb776a0555..aa1ab1648f8 100644 --- a/test/src/alloc-tests.el +++ b/test/src/alloc-tests.el @@ -51,3 +51,10 @@ (should-not (eq x y)) (dotimes (i 4) (should (eql (aref x i) (aref y i)))))) + +;; Bug#39207 +(ert-deftest aset-nbytes-change () + (let ((s (make-string 1 ?a))) + (dolist (c (list 10003 ?b 128 ?c ?d (max-char) ?e)) + (aset s 0 c) + (should (equal s (make-string 1 c)))))) -- 2.39.2