@matheusbsbs / matheus-bagliano / commits / 1aca69c019

perl Git::LoadCPAN: emit better errors under NO_PERL_CPAN_FALLBACKS

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 <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Ævar Arnfjörð Bjarmason committed Mar 3, 2018 at 15:38 UTC 1aca69c0195bd4ac671e7a36cf9b967d2bcbe200
3 files changed +44 -5
INSTALL
+8 -3
@@ -88,9 +88,9 @@ Issues of note:
88 export GIT_EXEC_PATH PATH GITPERLLIB
89
90 - By default (unless NO_PERL is provided) Git will ship various perl
91 - scripts & libraries it needs. However, for simplicity it doesn't
92 - use the ExtUtils::MakeMaker toolchain to decide where to place the
93 - perl libraries. Depending on the system this can result in the perl
91 + scripts. However, for simplicity it doesn't use the
92 + ExtUtils::MakeMaker toolchain to decide where to place the perl
93 + libraries. Depending on the system this can result in the perl
94 libraries not being where you'd like them if they're expected to be
95 used by things other than Git itself.
96
@@ -102,6 +102,11 @@ Issues of note:
102 Will result in e.g. perllibdir=/usr/share/perl/5.26.1 on Debian,
103 perllibdir=/usr/share/perl5 (which we'd use by default) on CentOS.
104
105 + - Unless NO_PERL is provided Git will ship various perl libraries it
106 + needs. Distributors of Git will usually want to set
107 + NO_PERL_CPAN_FALLBACKS if NO_PERL is not provided to use their own
108 + copies of the CPAN modules Git needs.
109 +
110 - Git is reasonably self-sufficient, but does depend on a few external
111 programs and libraries. Git can be used without most of them by adding
112 the approriate "NO_<LIBRARY>=YesPlease" to the make command line or
Makefile
+4 -1
@@ -2314,11 +2314,14 @@ all:: $(LIB_PERL_GEN)
2314 ifndef NO_PERL_CPAN_FALLBACKS
2315 all:: $(LIB_CPAN_GEN)
2316 endif
2317 +NO_PERL_CPAN_FALLBACKS_SQ = $(subst ','\'',$(NO_PERL_CPAN_FALLBACKS))
2318 endif
2319
2320 perl/build/lib/%.pm: perl/%.pm
2321 $(QUIET_GEN)mkdir -p $(dir $@) && \
2321 - sed -e 's|@@LOCALEDIR@@|$(localedir_SQ)|g' < $< > $@
2322 + sed -e 's|@@LOCALEDIR@@|$(localedir_SQ)|g' \
2323 + -e 's|@@NO_PERL_CPAN_FALLBACKS@@|$(NO_PERL_CPAN_FALLBACKS_SQ)|g' \
2324 + < $< > $@
2325
2326 perl/build/man/man3/Git.3pm: perl/Git.pm
2327 $(QUIET_GEN)mkdir -p $(dir $@) && \
perl/Git/LoadCPAN.pm
+32 -1
@@ -19,13 +19,25 @@ attempt to load C<Module::Name> from the OS, and if that doesn't work
19 will fall back on C<FromCPAN::Module::Name> shipped with Git itself.
20
21 Usually distributors will not ship with Git's Git::FromCPAN tree at
22 -all, preferring to use their own packaging of CPAN modules instead.
22 +all via the C<NO_PERL_CPAN_FALLBACKS> option, preferring to use their
23 +own packaging of CPAN modules instead.
24
25 This module is only intended to be used for code shipping in the
26 C<git.git> repository. Use it for anything else at your peril!
27
28 =cut
29
30 +# NO_PERL_CPAN_FALLBACKS_STR evades the sed search-replace from the
31 +# Makefile, and allows for detecting whether the module is loaded from
32 +# perl/Git as opposed to perl/build/Git, which is useful for one-off
33 +# testing without having Error.pm et al installed.
34 +use constant NO_PERL_CPAN_FALLBACKS_STR => '@@' . 'NO_PERL_CPAN_FALLBACKS' . '@@';
35 +use constant NO_PERL_CPAN_FALLBACKS => (
36 + q[@@NO_PERL_CPAN_FALLBACKS@@] ne ''
37 + and
38 + q[@@NO_PERL_CPAN_FALLBACKS@@] ne NO_PERL_CPAN_FALLBACKS_STR
39 +);
40 +
41 sub import {
42 shift;
43 my $caller = caller;
@@ -45,6 +57,25 @@ sub import {
57 } or do {
58 my $error = $@ || "Zombie Error";
59
60 + if (NO_PERL_CPAN_FALLBACKS) {
61 + chomp(my $error = sprintf <<'THEY_PROMISED', $module);
62 +BUG: The '%s' module is not here, but NO_PERL_CPAN_FALLBACKS was set!
63 +
64 +Git needs this Perl module from the CPAN, and will by default ship
65 +with a copy of it. This Git was built with NO_PERL_CPAN_FALLBACKS,
66 +meaning that whoever built it promised to provide this module.
67 +
68 +You're seeing this error because they broke that promise, and we can't
69 +load our fallback version, since we were asked not to install it.
70 +
71 +If you're seeing this error and didn't package Git yourself the
72 +package you're using is broken, or your system is broken. This error
73 +won't appear if Git is built without NO_PERL_CPAN_FALLBACKS (instead
74 +we'll use our fallback version of the module).
75 +THEY_PROMISED
76 + die $error;
77 + }
78 +
79 my $Git_LoadCPAN_pm_path = $INC{"Git/LoadCPAN.pm"} || die "BUG: Should have our own path from %INC!";
80
81 require File::Basename;