bug#24531: process-send-string seems to truncate lines over 4096 characters

[talwrii talwrii <talwrii@gmail.com>]

[-- Attachment #1.1: Type: text/plain, Size: 1689 bytes --]

=== Repro ===

i. Download attached el file
ii. Read it to ensure I am not hacking your computer
iii. In the same directory run

emacs -Q --eval '(progn (load-file "line-repro.el") (message (format "%S"
(repro))))' -nw --batch

As the last line of output I get

(3005 4100 6006)

I wouild expect this 4100 to be 5005

The third value indicates it is the line that gets truncated rather than
the string

=== Version details ===

In GNU Emacs 24.5.1 (x86_64-pc-linux-gnu, GTK+ Version 3.18.9) of
2016-04-08 on binet, modified by Debian Windowing system distributor `The
X.Org Foundation', version 11.0.11804000 System Description: Debian
GNU/Linux testing (stretch) Configured using: `configure --build
x86_64-linux-gnu --prefix=/usr --sharedstatedir=/var/lib
--libexecdir=/usr/lib --localstatedir=/var/lib --infodir=/usr/share/info
--mandir=/usr/share/man --with-pop=yes
--enable-locallisppath=/etc/emacs24:/etc/emacs:/usr/local/share/emacs/24.5/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.5/site-lisp:/usr/share/emacs/site-lisp
--build x86_64-linux-gnu --prefix=/usr --sharedstatedir=/var/lib
--libexecdir=/usr/lib --localstatedir=/var/lib --infodir=/usr/share/info
--mandir=/usr/share/man --with-pop=yes
--enable-locallisppath=/etc/emacs24:/etc/emacs:/usr/local/share/emacs/24.5/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.5/site-lisp:/usr/share/emacs/site-lisp
--with-x=yes --with-x-toolkit=gtk3 --with-toolkit-scroll-bars 'CFLAGS=-g
-O2 -fstack-protector-strong -Wformat -Werror=format-security -Wall'
'CPPFLAGS=-Wdate-time -D_FORTIFY_SOURCE=2' LDFLAGS=-Wl,-z,relro' Important
settings: value of $LANG: en_GB.UTF-8 locale-coding-system: utf-8-unix

[-- Attachment #1.2: Type: text/html, Size: 1994 bytes --]

[-- Attachment #2: line-repro.el --]
[-- Type: text/x-emacs-lisp, Size: 1741 bytes --]


(defun s-repeat (num s)
  ;; extracted from s.el
  "Make a string of S repeated NUM times."
  (let (ss)
    (while (> num 0)
      (setq ss (cons s ss))
      (setq num (1- num)))
    (apply 'concat ss)))

(defun s-concat (&rest strings)
  ;; extracted from s.el
  "Join all the string arguments into one string."
  (apply 'concat strings))

(setq tee-program "
import fcntl
import os
import select
import sys

fd = sys.stdin.fileno()
fl = fcntl.fcntl(fd, fcntl.F_GETFL)
fcntl.fcntl(fd, fcntl.F_SETFL, fl | os.O_NONBLOCK)

filename, = sys.argv[1:]

with open(filename, 'w') as stream:
    while True:
        select.select([sys.stdin], [], [sys.stdin], 0.2)
        data = sys.stdin.read()
        if data == '':
            break
        else:
            stream.write(data)
            stream.flush()
")

(defun repro ()
  (list
     (length (write-to-file (s-repeat 3000 "a")))
     (length (write-to-file (s-repeat 5000 "a")))
     (length (write-to-file (s-concat (s-repeat 3000 "a") "\n" (s-repeat 3000 "a"))))
     ))

(defun write-to-file (input)
  (let (p)

    (if (not (file-exists-p "/tmp/bettertee.py"))
        (write-region tee-program nil "/tmp/bettertee.py"))

    (setq p (start-process "bocp" "*bocp*"
                           "python" "/tmp/bettertee.py" "/tmp/line-repro-bug"))
    (process-send-string p input)
    (process-send-string p "\nnext")
    (process-send-eof p)

    (message (format "Waiting for process to die"))
    (while (process-live-p p)
      (sit-for 0.1))
    (message "Process is dead")
    (get-string-from-file "/tmp/line-repro-bug")
    ))

(defun get-string-from-file (filePath)
  "Return filePath's file content."
  (with-temp-buffer
    (insert-file-contents filePath) (buffer-string)))