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[bug#44663] [PATCH] ui: Launch $PAGER through the shell.
From: |
Tobias Geerinckx-Rice |
Subject: |
[bug#44663] [PATCH] ui: Launch $PAGER through the shell. |
Date: |
Sun, 15 Nov 2020 20:46:47 +0100 |
Guix,
Tobias Geerinckx-Rice via Guix-patches via 写道:
This is the convention elsewhere and sounds like the right thing
to do.
Before this patch, using PAGER= failed:
$ PAGER= guix search e
In execvp of : No such file or directory
$
With it, it fails in a slightly worse way:
$ PAGER= guix search e
$ # nothing, because we spawn the shell that swallows all
Attached are two possible solutions. One falls back to ‘less’,
the other to no paging.
I think I prefer the former (‘Ignore empty $PAGER variables’)
because the concept of ‘unset but empty’ could confuse ‘users’.
Is that too patronising? Do tell.
Kind regards,
T G-R
From dc64aadd9b124df37fcdf2f6dc057b61cf05a473 Mon Sep 17 00:00:00 2001
From: Tobias Geerinckx-Rice <me@tobias.gr>
Date: Sun, 15 Nov 2020 20:36:32 +0100
Subject: [PATCH] ui: Ignore empty $PAGER variables.
* guix/ui.scm (call-with-paginated-output-port): Treat "" as unset.
---
guix/ui.scm | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/guix/ui.scm b/guix/ui.scm
index 66614eef7c..584afc65dd 100644
--- a/guix/ui.scm
+++ b/guix/ui.scm
@@ -1673,8 +1673,11 @@ zero means that PACKAGE does not match any of REGEXPS."
;; 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")
+ ;; Ignore environment variables set to "" as if unset.
+ (open-pipe (find (lambda (s) (and s (not (string=? ""
s))))
+ (list (getenv "GUIX_PAGER")
+ (getenv "PAGER")
+ "less"))
OPEN_WRITE))))
(dynamic-wind
(const #t)
--
2.29.2
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(-)
diff --git a/guix/ui.scm b/guix/ui.scm
index 66614eef7c..bb03e06759 100644
--- a/guix/ui.scm
+++ b/guix/ui.scm
@@ -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
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