From b635c548c681532335b89b39e0642ecdf7bf1d9c Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Sat, 26 May 2018 13:29:06 -0700 Subject: [PATCH] =?utf8?q?Don=E2=80=99t=20set=20EMACS=3Dt=20if=20Bash=20is?= =?utf8?q?=204.4=20or=20newer?= MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit (Backport from master.) (Thanks to Stefan Monnier for improvements to this patch.) * lisp/term.el (term--bash-needs-EMACS-status): New var. (term--bash-needs-EMACSp): New function. (term-exec-1): Use it instead of always setting EMACS. --- lisp/term.el | 34 ++++++++++++++++++++++++++++------ 1 file changed, 28 insertions(+), 6 deletions(-) diff --git a/lisp/term.el b/lisp/term.el index 60cd547f93d..b7f5b0e7f20 100644 --- a/lisp/term.el +++ b/lisp/term.el @@ -1520,6 +1520,31 @@ Using \"emacs\" loses, because bash disables editing if $TERM == emacs.") ;; don't define :te=\\E[2J\\E[?47l\\E8:ti=\\E7\\E[?47h\ "Termcap capabilities supported.") +;; This private hack is for backwards compatibility with Bash 4.3 and earlier. +;; It can be useful even when running a program other than Bash, as the +;; program might invoke Bash as an interactive subshell. See this thread: +;; https://lists.gnu.org/r/emacs-devel/2018-05/msg00670.html +;; Remove this hack and its uses once Bash 4.4-or-later is reasonably +;; universal, because it slows down execution slightly when +;; term--bash-needs-EMACSp is first called. +(defvar term--bash-needs-EMACS-status nil + "43 if Bash is so old that it needs EMACS set. +Some other integer if Bash is new or not in use. +Nil if unknown.") +(defun term--bash-needs-EMACSp () + "t if Bash is old, nil if it is new or not in use." + (eq 43 + (or term--bash-needs-EMACS-status + (setf + term--bash-needs-EMACS-status + (let ((process-environment + (cons "BASH_ENV" process-environment))) + (condition-case nil + (call-process + "bash" nil nil nil "-c" + "case $BASH_VERSION in [0123].*|4.[0123].*) exit 43;; esac") + (error 0))))))) + ;; This auxiliary function cranks up the process for term-exec in ;; the appropriate environment. @@ -1537,12 +1562,6 @@ Using \"emacs\" loses, because bash disables editing if $TERM == emacs.") (format term-termcap-format "TERMCAP=" term-term-name term-height term-width) - ;; This is for backwards compatibility with Bash 4.3 and earlier. - ;; Remove this hack once Bash 4.4-or-later is common, because - ;; it breaks './configure' of some packages that expect it to - ;; say where to find EMACS. - (format "EMACS=%s (term:%s)" emacs-version term-protocol-version) - (format "INSIDE_EMACS=%s,term:%s" emacs-version term-protocol-version) (format "LINES=%d" term-height) (format "COLUMNS=%d" term-width)) @@ -1554,6 +1573,9 @@ Using \"emacs\" loses, because bash disables editing if $TERM == emacs.") ;; escape codes, so we need to see the raw output. We will have to ;; do the decoding by hand on the parts that are made of chars. (coding-system-for-read 'binary)) + (when (term--bash-needs-EMACSp) + (push (format "EMACS=%s (term:%s)" emacs-version term-protocol-version) + process-environment)) (apply 'start-process name buffer "/bin/sh" "-c" (format "stty -nl echo rows %d columns %d sane 2>/dev/null;\ -- 2.39.2