From 1aca69c0195bd4ac671e7a36cf9b967d2bcbe200 Mon Sep 17 00:00:00 2001 From: =?utf8?q?=C3=86var=20Arnfj=C3=B6r=C3=B0=20Bjarmason?= Date: Sat, 3 Mar 2018 15:38:17 +0000 Subject: [PATCH] perl Git::LoadCPAN: emit better errors under NO_PERL_CPAN_FALLBACKS MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Before my 20d2a30f8f ("Makefile: replace perl/Makefile.PL with simple make rules", 2017-12-10) on an OS package that removed the private-Error.pm copy we carried around manually removing the OS's Error.pm would yield: $ git add -p Can't locate Error.pm in @INC (you may need to install the Error module) [...] Now, before this change we'll instead emit this more cryptic error: $ git add -p BUG: '/usr/share/perl5/Git/FromCPAN' should be a directory! at /usr/share/perl5/Git/Error.pm line 36. This is a confusing error. Now if the new NO_PERL_CPAN_FALLBACKS option is specified and we can't find the module we'll instead emit: $ /tmp/git/bin/git add -p BUG: The 'Error' module is not here, but NO_PERL_CPAN_FALLBACKS was set! [...] Where [...] is the lengthy explanation seen in the change below, which explains what the potential breakage is, and how to fix it. The reason for checking @@NO_PERL_CPAN_FALLBACKS@@] against the empty string in Perl is as opposed to checking for a boolean value is that that's (as far as I can tell) make's idea of a string that's set, and e.g. NO_PERL_CPAN_FALLBACKS=0 is enough to set NO_PERL_CPAN_FALLBACKS. Signed-off-by: Ævar Arnfjörð Bjarmason Signed-off-by: Junio C Hamano --- INSTALL | 11 ++++++++--- Makefile | 5 ++++- perl/Git/LoadCPAN.pm | 33 ++++++++++++++++++++++++++++++++- 3 files changed, 44 insertions(+), 5 deletions(-) diff --git a/INSTALL b/INSTALL index 808e07b659..60e515eaf7 100644 --- a/INSTALL +++ b/INSTALL @@ -88,9 +88,9 @@ Issues of note: export GIT_EXEC_PATH PATH GITPERLLIB - By default (unless NO_PERL is provided) Git will ship various perl - scripts & libraries it needs. However, for simplicity it doesn't - use the ExtUtils::MakeMaker toolchain to decide where to place the - perl libraries. Depending on the system this can result in the perl + scripts. However, for simplicity it doesn't use the + ExtUtils::MakeMaker toolchain to decide where to place the perl + libraries. Depending on the system this can result in the perl libraries not being where you'd like them if they're expected to be used by things other than Git itself. @@ -102,6 +102,11 @@ Issues of note: Will result in e.g. perllibdir=/usr/share/perl/5.26.1 on Debian, perllibdir=/usr/share/perl5 (which we'd use by default) on CentOS. + - Unless NO_PERL is provided Git will ship various perl libraries it + needs. Distributors of Git will usually want to set + NO_PERL_CPAN_FALLBACKS if NO_PERL is not provided to use their own + copies of the CPAN modules Git needs. + - Git is reasonably self-sufficient, but does depend on a few external programs and libraries. Git can be used without most of them by adding the approriate "NO_=YesPlease" to the make command line or diff --git a/Makefile b/Makefile index 518c5f6be0..4e0cdb3ca4 100644 --- a/Makefile +++ b/Makefile @@ -2314,11 +2314,14 @@ all:: $(LIB_PERL_GEN) ifndef NO_PERL_CPAN_FALLBACKS all:: $(LIB_CPAN_GEN) endif +NO_PERL_CPAN_FALLBACKS_SQ = $(subst ','\'',$(NO_PERL_CPAN_FALLBACKS)) endif perl/build/lib/%.pm: perl/%.pm $(QUIET_GEN)mkdir -p $(dir $@) && \ - sed -e 's|@@LOCALEDIR@@|$(localedir_SQ)|g' < $< > $@ + sed -e 's|@@LOCALEDIR@@|$(localedir_SQ)|g' \ + -e 's|@@NO_PERL_CPAN_FALLBACKS@@|$(NO_PERL_CPAN_FALLBACKS_SQ)|g' \ + < $< > $@ perl/build/man/man3/Git.3pm: perl/Git.pm $(QUIET_GEN)mkdir -p $(dir $@) && \ diff --git a/perl/Git/LoadCPAN.pm b/perl/Git/LoadCPAN.pm index 229c1ee87d..e5585e75e8 100644 --- a/perl/Git/LoadCPAN.pm +++ b/perl/Git/LoadCPAN.pm @@ -19,13 +19,25 @@ attempt to load C from the OS, and if that doesn't work will fall back on C shipped with Git itself. Usually distributors will not ship with Git's Git::FromCPAN tree at -all, preferring to use their own packaging of CPAN modules instead. +all via the C option, preferring to use their +own packaging of CPAN modules instead. This module is only intended to be used for code shipping in the C repository. Use it for anything else at your peril! =cut +# NO_PERL_CPAN_FALLBACKS_STR evades the sed search-replace from the +# Makefile, and allows for detecting whether the module is loaded from +# perl/Git as opposed to perl/build/Git, which is useful for one-off +# testing without having Error.pm et al installed. +use constant NO_PERL_CPAN_FALLBACKS_STR => '@@' . 'NO_PERL_CPAN_FALLBACKS' . '@@'; +use constant NO_PERL_CPAN_FALLBACKS => ( + q[@@NO_PERL_CPAN_FALLBACKS@@] ne '' + and + q[@@NO_PERL_CPAN_FALLBACKS@@] ne NO_PERL_CPAN_FALLBACKS_STR +); + sub import { shift; my $caller = caller; @@ -45,6 +57,25 @@ sub import { } or do { my $error = $@ || "Zombie Error"; + if (NO_PERL_CPAN_FALLBACKS) { + chomp(my $error = sprintf <<'THEY_PROMISED', $module); +BUG: The '%s' module is not here, but NO_PERL_CPAN_FALLBACKS was set! + +Git needs this Perl module from the CPAN, and will by default ship +with a copy of it. This Git was built with NO_PERL_CPAN_FALLBACKS, +meaning that whoever built it promised to provide this module. + +You're seeing this error because they broke that promise, and we can't +load our fallback version, since we were asked not to install it. + +If you're seeing this error and didn't package Git yourself the +package you're using is broken, or your system is broken. This error +won't appear if Git is built without NO_PERL_CPAN_FALLBACKS (instead +we'll use our fallback version of the module). +THEY_PROMISED + die $error; + } + my $Git_LoadCPAN_pm_path = $INC{"Git/LoadCPAN.pm"} || die "BUG: Should have our own path from %INC!"; require File::Basename; -- 2.11.4.GIT