From e1cf7e852c4a4c0cfce8c0de5625d026229dd71b Mon Sep 17 00:00:00 2001
From: Tobias Geerinckx-Rice <me@tobias.gr>
Date: Sun, 15 Nov 2020 20:26:54 +0100
Subject: [PATCH] ui: Disable paging if $PAGER is set to the empty string.
* guix/ui.scm (call-with-paginated-output-port): Don't open a pipe if $PAGER is "".
---
guix/ui.scm | 39 +++++++++++++++++++++------------------
1 file changed, 21 insertions(+), 18 deletions(-)
@@ -1663,24 +1663,27 @@ zero means that PACKAGE does not match any of REGEXPS."
(define* (call-with-paginated-output-port proc
#:key (less-options "FrX"))
- (if (isatty?* (current-output-port))
- ;; Set 'LESS' so that 'less' exits if everything fits on the screen (F),
- ;; lets ANSI escapes through (r), does not send the termcap
- ;; initialization string (X). Set it unconditionally because some
- ;; distros set it to something that doesn't work here.
- ;;
- ;; For things that produce long lines, such as 'guix processes', use 'R'
- ;; instead of 'r': this strips hyperlinks but allows 'less' to make a
- ;; good estimate of the line length.
- (let ((pager (with-environment-variables `(("LESS" ,less-options))
- (open-pipe (or (getenv "GUIX_PAGER") (getenv "PAGER")
- "less")
- OPEN_WRITE))))
- (dynamic-wind
- (const #t)
- (lambda () (proc pager))
- (lambda () (close-pipe pager))))
- (proc (current-output-port))))
+ (let ((command (or (getenv "GUIX_PAGER") (getenv "PAGER")
+ "less")))
+ ;; If a user types ‘PAGER= guix foo’ their intention is probably to disable
+ ;; paging entirely, not to use Guix's default pager.
+ (if (and (not (string=? "" command))
+ (isatty?* (current-output-port)))
+ ;; Set 'LESS' so that 'less' exits if everything fits on the screen (F),
+ ;; lets ANSI escapes through (r), does not send the termcap
+ ;; initialization string (X). Set it unconditionally because some
+ ;; distros set it to something that doesn't work here.
+ ;;
+ ;; For things that produce long lines, such as 'guix processes', use 'R'
+ ;; instead of 'r': this strips hyperlinks but allows 'less' to make a
+ ;; good estimate of the line length.
+ (let ((pager (with-environment-variables `(("LESS" ,less-options))
+ (open-pipe command OPEN_WRITE))))
+ (dynamic-wind
+ (const #t)
+ (lambda () (proc pager))
+ (lambda () (close-pipe pager))))
+ (proc (current-output-port)))))
(define-syntax with-paginated-output-port
(syntax-rules ()
--
2.29.2