bug#35927: 26.2; url-http-end-of-headers sets to 1 when cache is working

["Basil L. Contovounesios" <contovob@tcd.ie>]

Xu Chunyang <mail@xuchunyang.me> writes:

> Today I enable URL cache via
>
>     (setq url-automatic-caching t
>           url-cache-expire-time (* 6 3600))
>
> and I notice url-http-end-of-headers isn't the end of the headers when
> cache is working. This breaks some of my code, I assume it is the end of
> the header so I use (goto-char url-http-end-of-headers) before parsing
> the response body. Is this expected or a bug?
>
>     (with-current-buffer (url-retrieve-synchronously "http://example.com")
>       (message "=> %S" url-http-end-of-headers))
>     "=> #<marker at 347 in  *http example.com:80*>"
>     
>     (with-current-buffer (url-retrieve-synchronously "http://example.com")
>       (message "=> %S" url-http-end-of-headers))
>     "=> #<marker at 1 in  *http example.com:80*-325608>"
>     
>     (with-current-buffer (url-retrieve-synchronously "http://example.com")
>       (message "=> %S" url-http-end-of-headers))
>     "=> #<marker at 1 in  *http example.com:80*-887290>"

I can't seem to reproduce this on emacs-26 or master:

0. HOME=$(mktemp -d) emacs -Q
1. (let ((get (lambda ()
                (with-current-buffer
                    (url-retrieve-synchronously "https://gnu.org")
                  (message "%s" url-http-end-of-headers)))))
     (dotimes (_ 3) (funcall get))
     (setq url-automatic-caching t
           url-cache-expire-time (* 6 3600))
     (dotimes (_ 3) (funcall get)))
2. C-x C-e

Contacting host: gnu.org:443
#<marker at 470 in  *http www.gnu.org:443*>
Contacting host: gnu.org:443
#<marker at 469 in  *http www.gnu.org:443*-93923>
#<marker at 469 in  *http www.gnu.org:443*-669963>
Contacting host: gnu.org:443
#<marker at 469 in  *http www.gnu.org:443*-843863>
#<marker at 469 in  *http www.gnu.org:443*-298952>
#<marker at 469 in  *http www.gnu.org:443*-323128>

What am I doing wrong?

-- 
Basil

In GNU Emacs 26.2.50 (build 8, x86_64-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2019-05-27 built on thunk
Repository revision: c4d4dcf17e407a3c68e150f22b9756ef6c943070
Windowing system distributor 'The X.Org Foundation', version 11.0.12003000
System Description:	Debian GNU/Linux 10 (buster)

Configured using:
 'configure 'CC=ccache gcc' 'CFLAGS=-O0 -g3 -ggdb -gdwarf-4'
 --config-cache --prefix=/home/blc/.local --program-suffix=26
 --enable-checking=yes,glyphs --enable-check-lisp-object-type
 --with-mailutils --with-x-toolkit=lucid --with-modules
 --with-file-notification=yes --with-x'

Configured features:
XAW3D XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GSETTINGS
GLIB NOTIFY ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT
ZLIB TOOLKIT_SCROLL_BARS LUCID X11 XDBE XIM MODULES THREADS LIBSYSTEMD
LCMS2

Important settings:
  value of $LANG: en_IE.UTF-8
  locale-coding-system: utf-8-unix


In GNU Emacs 27.0.50 (build 6, x86_64-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2019-05-25 built on thunk
Repository revision: ec4b2c888ad12c255accf1bccdac12f173c96047
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12003000
System Description: Debian GNU/Linux 10 (buster)

Configured using:
 'configure 'CC=ccache gcc' 'CFLAGS=-O2 -march=native' --config-cache
 --prefix=/home/blc/.local --with-mailutils --with-x-toolkit=lucid
 --with-modules --with-file-notification=yes --with-x'

Configured features:
XAW3D XPM JPEG TIFF GIF PNG RSVG SOUND GPM DBUS GSETTINGS GLIB NOTIFY
INOTIFY ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS LUCID X11 XDBE XIM MODULES THREADS LIBSYSTEMD JSON
PDUMPER LCMS2 GMP