From 3c66c6f163e72da7b8f5d40dab7cb2655faddf47 Mon Sep 17 00:00:00 2001 From: Noam Postavsky Date: Sun, 10 Jul 2016 21:52:23 -0400 Subject: [PATCH v2] Document buffer-swap-text+save-excursion interaction * doc/lispref/buffers.texi (Swapping Text): * src/buffer.c (Fbuffer_swap_text): Add warning about interaction of `buffer-swap-text' and `save-excursion' (Bug #4655). --- doc/lispref/buffers.texi | 5 +++++ src/buffer.c | 4 +++- 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/doc/lispref/buffers.texi b/doc/lispref/buffers.texi index 1f7f263..e10c2b3 100644 --- a/doc/lispref/buffers.texi +++ b/doc/lispref/buffers.texi @@ -1211,6 +1211,11 @@ Swapping Text overlays, the text properties, the undo list, the value of the @code{enable-multibyte-characters} flag (@pxref{Text Representations, enable-multibyte-characters}), etc. + +@strong{Warning:} If called from within @code{save-excursion}, this +function will set the saved buffer to @var{buffer}, since the +marker used by @code{save-excursion} to save the position and buffer +will be swapped as well. @end defun If you use @code{buffer-swap-text} on a file-visiting buffer, you diff --git a/src/buffer.c b/src/buffer.c index e4269c0..89f4479 100644 --- a/src/buffer.c +++ b/src/buffer.c @@ -2231,7 +2231,9 @@ advance_to_char_boundary (ptrdiff_t byte_pos) DEFUN ("buffer-swap-text", Fbuffer_swap_text, Sbuffer_swap_text, 1, 1, 0, - doc: /* Swap the text between current buffer and BUFFER. */) + doc: /* Swap the text between current buffer and BUFFER. +Using this function from `save-excursion' might produce surprising +results, see Info node `(elisp)Swapping Text'. */) (Lisp_Object buffer) { struct buffer *other_buffer; -- 2.8.0