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Re: [PATCH 3/8] perl: generalize the Git::LoadCPAN facility

From
Todd Zullinger <tmz@pobox.com>
Date
Feb 17, 2018, 05:40 UTC
Message-ID
<20180217054052.GU27038@zaya.teonanacatl.net>
In-Reply-To
<20180217004753.GS27038@zaya.teonanacatl.net>
I wrote:
Show 45 quoted lines
> Hi Jonathan,
> 
> Jonathan Nieder wrote:
>> Todd Zullinger wrote:
> [...]
>>> +++ b/Makefile
>>> @@ -296,6 +296,9 @@ all::
>>>  #
>>>  # Define NO_PERL if you do not want Perl scripts or libraries at all.
>>>  #
>>> +# Define NO_PERL_CPAN_FALLBACKS if you do not want to install fallbacks for
>>> +# perl CPAN modules.
>> 
>> nit: Looking at this as a naive user, it's not obvious what kind of
>> fallbacks are meant. How about:
>> 
>> 	Define NO_PERL_CPAN_FALLBACKS if you do not want to install bundled
>> 	copies of CPAN modules that serve as a fallback in case the modules are
>> 	not available on the system.
>> 
>> Or perhaps:
>> 
>> 	Define HAVE_CPAN_MODULES if you have Error.pm and Mail::Address installed
>> 	and do not want to install the fallback copies from perl/FromCPAN.
> 
> Hmm, a positive variable like HAVE_CPAN_MODULES is
> appealing.
> 
> I don't know about listing the modules, as those seem likely
> to change and then the comment becomes stale.  It's nice to
> have a shorter name.  I could easily go back and forth.
> Hopefully some other folks will chime in with preferences.
> 
>> Would this patch need to update the loader to expect the modules in
>> the new location?
> 
> That's a good catch.  In checking how this ends up when not
> setting NO_PERL_CPAN_FALLBACKS, we end up installing
> FromCPAN at the root of $perllibdir rather than under the
> Git dir.
> 
> While we could probably fix Git::LoadCPAN, I doubt we want
> to pollute the namespace. ;) So we'll want to ensure the
> files get put in the right place from the start.  I'll try
> to fix that up.

I ended up adding a second variable to hold the FromCPAN wildcard match, as I couldn't come up with any clean way to do it in the same LIB_PERL{,_GEN} vars.

I tested it with and without NO_PERL_CPAN_FALLBACKS set and with and without the system Error and Mail::Address modules installed. There's nothing which automatically removes the perl/build/lib/Git/FromCPAN tree if make was run without NO_PERL_CPAN_FALLBACKS set and then re-run with it. I don't know if that's something we'd care to support or not. I suspect it's simpler to require 'make clean' between such runs.

(I had to restore the FromCPAN copy of Address.pm, as noted in <87tvuif10e.fsf@evledraar.gmail.com>, of course.)

Here's what it looks like now (still subject to changing the NO_PERL_CPAN_FALLBACKS variable).

---- 8> ----
From: Todd Zullinger <tmz@pobox.com>
Subject: [PATCH] Makefile: add NO_PERL_CPAN_FALLBACKS knob

We include some perl modules which are not part of the core perl install, as a convenience. This allows us to rely on those modules in our perl-based tools and scripts without requiring users to install the modules from CPAN or their operating system packages.

Users whose operating system provides these modules and packagers of Git often don't want to ship or use these bundled modules. Allow these users to set NO_PERL_CPAN_FALLBACKS to avoid installing the bundled modules.

Signed-off-by: Todd Zullinger <tmz@pobox.com>
---
 Makefile                                    | 14 ++++++++++++++
 perl/{Git => }/FromCPAN/.gitattributes      |  0
 perl/{Git => }/FromCPAN/Error.pm            |  0
 perl/{Git => }/FromCPAN/Mail/.gitattributes |  0
 perl/{Git => }/FromCPAN/Mail/Address.pm     |  0
 5 files changed, 14 insertions(+)
 rename perl/{Git => }/FromCPAN/.gitattributes (100%)
 rename perl/{Git => }/FromCPAN/Error.pm (100%)
 rename perl/{Git => }/FromCPAN/Mail/.gitattributes (100%)
 rename perl/{Git => }/FromCPAN/Mail/Address.pm (100%)
diff --git a/Makefile b/Makefile
index bdd50069af..49244fb116 100644
--- a/Makefile
+++ b/Makefile
@@ -296,6 +296,10 @@ all::
 #
 # Define NO_PERL if you do not want Perl scripts or libraries at all.
 #
+# Define NO_PERL_CPAN_FALLBACKS if you do not want to install bundled
+# copies of CPAN modules that serve as a fallback in case the modules are
+# not available on the system.
+#
 # Define PYTHON_PATH to the path of your Python binary (often /usr/bin/python
 # but /usr/bin/python2.7 on some platforms).
 #
@@ -2300,15 +2304,25 @@ po/build/locale/%/LC_MESSAGES/git.mo: po/%.po
 
 LIB_PERL := $(wildcard perl/Git.pm perl/Git/*.pm perl/Git/*/*.pm perl/Git/*/*/*.pm)
 LIB_PERL_GEN := $(patsubst perl/%.pm,perl/build/lib/%.pm,$(LIB_PERL))
+ifndef NO_PERL_CPAN_FALLBACKS
+LIB_CPAN := $(wildcard perl/FromCPAN/*.pm perl/FromCPAN/*/*.pm)
+LIB_CPAN_GEN := $(patsubst perl/%.pm,perl/build/lib/Git/%.pm,$(LIB_CPAN))
+endif
 
 ifndef NO_PERL
 all:: $(LIB_PERL_GEN)
+ifndef NO_PERL_CPAN_FALLBACKS
+all:: $(LIB_CPAN_GEN)
+endif
 endif
 
 perl/build/lib/%.pm: perl/%.pm
 	$(QUIET_GEN)mkdir -p $(dir $@) && \
 	sed -e 's|@@LOCALEDIR@@|$(localedir_SQ)|g' < $< > $@
 
+perl/build/lib/Git/FromCPAN/%.pm: perl/FromCPAN/%.pm
+	$(QUIET_GEN)mkdir -p $(dir $@) && cp $< $@
+
 perl/build/man/man3/Git.3pm: perl/Git.pm
 	$(QUIET_GEN)mkdir -p $(dir $@) && \
 	pod2man $< $@
diff --git a/perl/Git/FromCPAN/.gitattributes b/perl/FromCPAN/.gitattributes
similarity index 100%
rename from perl/Git/FromCPAN/.gitattributes
rename to perl/FromCPAN/.gitattributes
diff --git a/perl/Git/FromCPAN/Error.pm b/perl/FromCPAN/Error.pm
similarity index 100%
rename from perl/Git/FromCPAN/Error.pm
rename to perl/FromCPAN/Error.pm
diff --git a/perl/Git/FromCPAN/Mail/.gitattributes b/perl/FromCPAN/Mail/.gitattributes
similarity index 100%
rename from perl/Git/FromCPAN/Mail/.gitattributes
rename to perl/FromCPAN/Mail/.gitattributes
diff --git a/perl/Git/FromCPAN/Mail/Address.pm b/perl/FromCPAN/Mail/Address.pm
similarity index 100%
rename from perl/Git/FromCPAN/Mail/Address.pm
rename to perl/FromCPAN/Mail/Address.pm

-- 
2.16.2

I thought about using '$(INSTALL) -m 644' instead of 'cp' to
allow users to set 'INSTALL = install -p' to preserve the
timestamp of the FromCPAN files, but that would only be
useful to users installing from the same tarball version
multiple times.  The intersection of users who care that
much about consistent timestamps and don't care about using
system perl modules seems small.

-- 
Todd
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
A person who smiles in the face of adversity ... probably has a
scapegoat.
Previous: Todd ZullingerNext: Ævar Arnfjörð Bjarmason
Message 22 of 66 in “various perl fixes”
  1. 0/8 various perl fixesÆvar Arnfjörð Bjarmason, Feb 14, 2018
  2. 1/8 perl: *.pm files should not have the executable bitÆvar Arnfjörð Bjarmason, Feb 14, 2018
  3. Jonathan NiederFeb 14, 2018
  4. Ævar Arnfjörð BjarmasonFeb 25, 2018
  5. 2/8 perl: move CPAN loader wrappers to another namespaceÆvar Arnfjörð Bjarmason, Feb 14, 2018
  6. Jonathan NiederFeb 14, 2018
  7. 4/8 perl: update our ancient copy of Error.pmÆvar Arnfjörð Bjarmason, Feb 14, 2018
  8. Jonathan NiederFeb 14, 2018
  9. Ævar Arnfjörð BjarmasonFeb 15, 2018
  10. 3/8 perl: generalize the Git::LoadCPAN facilityÆvar Arnfjörð Bjarmason, Feb 14, 2018
  11. Jonathan NiederFeb 14, 2018
  12. Todd ZullingerFeb 15, 2018
  13. Ævar Arnfjörð BjarmasonFeb 25, 2018
  14. Randall S. BeckerFeb 25, 2018
  15. Todd ZullingerFeb 15, 2018
  16. Ævar Arnfjörð BjarmasonFeb 15, 2018
  17. Todd ZullingerFeb 15, 2018
  18. Ævar Arnfjörð BjarmasonFeb 16, 2018
  19. Todd ZullingerFeb 16, 2018
  20. Jonathan NiederFeb 16, 2018
  21. Todd ZullingerFeb 17, 2018
  22. Todd ZullingerFeb 17, 2018
  23. 6/8 git-send-email: unconditionally use Net::{SMTP,Domain}Ævar Arnfjörð Bjarmason, Feb 14, 2018
  24. Jonathan NiederFeb 14, 2018
  25. Ævar Arnfjörð BjarmasonFeb 15, 2018
  26. 7/8 gitweb: hard-depend on the Digest::MD5 5.8 moduleÆvar Arnfjörð Bjarmason, Feb 14, 2018
  27. Jonathan NiederFeb 14, 2018
  28. 5/8 perl: update our copy of Mail::AddressÆvar Arnfjörð Bjarmason, Feb 14, 2018
  29. Jonathan NiederFeb 14, 2018
  30. Matthieu MoyFeb 15, 2018
  31. Ævar Arnfjörð BjarmasonFeb 15, 2018
  32. 8/8 perl: hard-depend on the File::{Temp,Spec} modulesÆvar Arnfjörð Bjarmason, Feb 14, 2018
  33. Jonathan NiederFeb 14, 2018
  34. Ævar Arnfjörð BjarmasonFeb 15, 2018
  35. Junio C HamanoFeb 15, 2018
  36. 00/13 various perl fixesÆvar Arnfjörð Bjarmason, Feb 25, 2018
  37. 01/13 perl: *.pm files should not have the executable bitÆvar Arnfjörð Bjarmason, Feb 25, 2018
  38. 02/13 Git.pm: remove redundant "use strict" from sub-packageÆvar Arnfjörð Bjarmason, Feb 25, 2018
  39. 03/13 Git.pm: add the "use warnings" pragmaÆvar Arnfjörð Bjarmason, Feb 25, 2018
  40. 04/13 gitweb: hard-depend on the Digest::MD5 5.8 moduleÆvar Arnfjörð Bjarmason, Feb 25, 2018
  41. Eric SunshineFeb 25, 2018
  42. 05/13 Git.pm: hard-depend on the File::{Temp,Spec} modulesÆvar Arnfjörð Bjarmason, Feb 25, 2018
  43. 07/13 perl: update our ancient copy of Error.pmÆvar Arnfjörð Bjarmason, Feb 25, 2018
  44. 06/13 git-send-email: unconditionally use Net::{SMTP,Domain}Ævar Arnfjörð Bjarmason, Feb 25, 2018
  45. Eric SunshineFeb 25, 2018
  46. 09/13 perl: move CPAN loader wrappers to another namespaceÆvar Arnfjörð Bjarmason, Feb 25, 2018
  47. 08/13 perl: update our copy of Mail::AddressÆvar Arnfjörð Bjarmason, Feb 25, 2018
  48. 10/13 perl: generalize the Git::LoadCPAN facilityÆvar Arnfjörð Bjarmason, Feb 25, 2018
  49. 11/13 perl: move the perl/Git/FromCPAN tree to perl/FromCPANÆvar Arnfjörð Bjarmason, Feb 25, 2018
  50. 13/13 perl Git::LoadCPAN: emit better errors under NO_PERL_CPAN_FALLBACKSÆvar Arnfjörð Bjarmason, Feb 25, 2018
  51. 12/13 Makefile: add NO_PERL_CPAN_FALLBACKS knobÆvar Arnfjörð Bjarmason, Feb 25, 2018
  52. 00/13 various perl fixesÆvar Arnfjörð Bjarmason, Mar 3, 2018
  53. 01/13 perl: *.pm files should not have the executable bitÆvar Arnfjörð Bjarmason, Mar 3, 2018
  54. 02/13 Git.pm: remove redundant "use strict" from sub-packageÆvar Arnfjörð Bjarmason, Mar 3, 2018
  55. 04/13 gitweb: hard-depend on the Digest::MD5 5.8 moduleÆvar Arnfjörð Bjarmason, Mar 3, 2018
  56. 05/13 Git.pm: hard-depend on the File::{Temp,Spec} modulesÆvar Arnfjörð Bjarmason, Mar 3, 2018
  57. 03/13 Git.pm: add the "use warnings" pragmaÆvar Arnfjörð Bjarmason, Mar 3, 2018
  58. 06/13 git-send-email: unconditionally use Net::{SMTP,Domain}Ævar Arnfjörð Bjarmason, Mar 3, 2018
  59. 10/13 perl: generalize the Git::LoadCPAN facilityÆvar Arnfjörð Bjarmason, Mar 3, 2018
  60. 11/13 perl: move the perl/Git/FromCPAN tree to perl/FromCPANÆvar Arnfjörð Bjarmason, Mar 3, 2018
  61. 12/13 Makefile: add NO_PERL_CPAN_FALLBACKS knobÆvar Arnfjörð Bjarmason, Mar 3, 2018
  62. 13/13 perl Git::LoadCPAN: emit better errors under NO_PERL_CPAN_FALLBACKSÆvar Arnfjörð Bjarmason, Mar 3, 2018
  63. 08/13 perl: update our copy of Mail::AddressÆvar Arnfjörð Bjarmason, Mar 3, 2018
  64. 09/13 perl: move CPAN loader wrappers to another namespaceÆvar Arnfjörð Bjarmason, Mar 3, 2018
  65. 07/13 perl: update our ancient copy of Error.pmÆvar Arnfjörð Bjarmason, Mar 3, 2018
  66. Junio C HamanoMar 5, 2018

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