From c8803d89fe531a1ff0de8ccdbc77c86249d5e778 Mon Sep 17 00:00:00 2001 From: Taiju HIGASHI Date: Wed, 8 Jun 2022 18:50:28 +0900 Subject: [PATCH] ui: Improve pager selection logic when less is not installed. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit * guix/ui.scm (find-available-pager): New procedure. (call-with-paginated-output-port): Use it. * guix/utils.scm (call-with-environment-variables): Allow clearing of specified environment variables. * tests/ui.scm (make-empty-file, assert-equals-find-available-pager): New procedures. ("find-available-pager, GUIX_PAGER takes precedence") ("find-available-pager, PAGER takes precedence") ("find-available-pager, 'less' takes precedence") ("find-available-pager, 'more' takes precedence") ("find-available-pager, no pager"): New tests. Co-authored-by: Ludovic Courtès --- guix/ui.scm | 14 ++++++++--- guix/utils.scm | 3 +++ tests/ui.scm | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 82 insertions(+), 3 deletions(-) diff --git a/guix/ui.scm b/guix/ui.scm index cb68a07c6c..a7acd41440 100644 --- a/guix/ui.scm +++ b/guix/ui.scm @@ -17,6 +17,7 @@ ;;; Copyright © 2020 Arun Isaac ;;; Copyright © 2020 Maxim Cournoyer ;;; Copyright © 2018 Steve Sprang +;;; Copyright © 2022 Taiju HIGASHI ;;; ;;; This file is part of GNU Guix. ;;; @@ -1672,11 +1673,18 @@ (define* (pager-wrapped-port #:optional (port (current-output-port))) (_ #f))) +(define (find-available-pager) + "Return the program name of an available pager or the empty string if none is +available." + (or (getenv "GUIX_PAGER") + (getenv "PAGER") + (which "less") + (which "more") + "")) + (define* (call-with-paginated-output-port proc #:key (less-options "FrX")) - (let ((pager-command-line (or (getenv "GUIX_PAGER") - (getenv "PAGER") - "less"))) + (let ((pager-command-line (find-available-pager))) ;; Setting PAGER to the empty string conventionally disables paging. (if (and (not (string-null? pager-command-line)) (isatty?* (current-output-port))) diff --git a/guix/utils.scm b/guix/utils.scm index 37b2e29800..5c36b15cfe 100644 --- a/guix/utils.scm +++ b/guix/utils.scm @@ -13,6 +13,7 @@ ;;; Copyright © 2021 Chris Marusich ;;; Copyright © 2021 Maxime Devos ;;; Copyright © 2018 Steve Sprang +;;; Copyright © 2022 Taiju HIGASHI ;;; ;;; This file is part of GNU Guix. ;;; @@ -158,6 +159,8 @@ (define (call-with-environment-variables variables thunk) (dynamic-wind (lambda () (for-each (match-lambda + ((variable #false) + (unsetenv variable)) ((variable value) (setenv variable value))) variables)) diff --git a/tests/ui.scm b/tests/ui.scm index 3dc6952e1f..6a25a204ca 100644 --- a/tests/ui.scm +++ b/tests/ui.scm @@ -1,5 +1,6 @@ ;;; GNU Guix --- Functional package management for GNU ;;; Copyright © 2013, 2014, 2015, 2016, 2017, 2019, 2020 Ludovic Courtès +;;; Copyright © 2022 Taiju HIGASHI ;;; ;;; This file is part of GNU Guix. ;;; @@ -24,6 +25,7 @@ (define-module (test-ui) #:use-module (guix derivations) #:use-module ((gnu packages) #:select (specification->package)) #:use-module (guix tests) + #:use-module (guix utils) #:use-module (srfi srfi-1) #:use-module (srfi srfi-11) #:use-module (srfi srfi-19) @@ -292,4 +294,70 @@ (define guile-2.0.9 (>0 (package-relevance libb2 (map rx '("crypto" "library"))))))) +(define (make-empty-file directory file) + ;; Create FILE in DIRECTORY. + (close-port (open-output-file (in-vicinity directory file)))) + +(define (assert-equals-find-available-pager expected) + ;; Use 'with-paginated-output-port' and return true if it invoked EXPECTED. + (define used-command "") + (mock ((ice-9 popen) open-pipe* + (lambda (mode command . args) + (unless (string-null? used-command) + (error "open-pipe* should only be called once")) + (set! used-command command) + (%make-void-port ""))) + (mock ((ice-9 popen) close-pipe (const 'ok)) + (mock ((guix colors) isatty?* (const #t)) + (with-paginated-output-port port 'ok) + (string=? expected used-command))))) + + +(test-assert "find-available-pager, GUIX_PAGER takes precedence" + (call-with-temporary-directory + (lambda (dir) + (with-environment-variables `(("PATH" ,dir) + ("GUIX_PAGER" "guix-pager") + ("PAGER" "pager")) + (make-empty-file dir "less") + (make-empty-file dir "more") + (assert-equals-find-available-pager "guix-pager"))))) + +(test-assert "find-available-pager, PAGER takes precedence" + (call-with-temporary-directory + (lambda (dir) + (with-environment-variables `(("PATH" ,dir) + ("GUIX_PAGER" #false) + ("PAGER" "pager")) + (make-empty-file dir "less") + (make-empty-file dir "more") + (assert-equals-find-available-pager "pager"))))) + +(test-assert "find-available-pager, 'less' takes precedence" + (call-with-temporary-directory + (lambda (dir) + (with-environment-variables `(("PATH" ,dir) + ("GUIX_PAGER" #false) + ("PAGER" #false)) + (make-empty-file dir "less") + (make-empty-file dir "more") + (assert-equals-find-available-pager (in-vicinity dir "less")))))) + +(test-assert "find-available-pager, 'more' takes precedence" + (call-with-temporary-directory + (lambda (dir) + (with-environment-variables `(("PATH" ,dir) + ("GUIX_PAGER" #false) + ("PAGER" #false)) + (make-empty-file dir "more") + (assert-equals-find-available-pager (in-vicinity dir "more")))))) + +(test-assert "find-available-pager, no pager" + (call-with-temporary-directory + (lambda (dir) + (with-environment-variables `(("PATH" ,dir) + ("GUIX_PAGER" #false) + ("PAGER" #false)) + (assert-equals-find-available-pager ""))))) + (test-end "ui")