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We set "use warnings" in most of our perl code to catch problems. But as
the name implies, warnings just emit a message to stderr and don't
otherwise affect the program. So our tests are quite likely to miss that
warnings are being spewed, as most of them do not look at stderr.
We could ask perl to make all warnings fatal, but this is likely
annoying for non-developers, who would rather have a running program
with a warning than something that refuses to work at all.
So instead, let's teach the perl code to respect an environment variable
(GIT_PERL_FATAL_WARNINGS) to increase the severity of the warnings. This
can be set for day-to-day running if people want to be really pedantic,
but the primary use is to trigger it within the test suite.
We could also trigger that for every test run, but likewise even the
tests failing may be annoying to distro builders, etc (just as -Werror
would be for compiling C code). So we'll tie it to a special test-mode
variable (GIT_TEST_PERL_FATAL_WARNINGS) that can be set in the
environment or as a Makefile knob, and we'll automatically turn the knob
when DEVELOPER=1 is set. That should give developers and CI the more
careful view without disrupting normal users or packagers.
Note that the mapping from the GIT_TEST_* form to the GIT_* form in
test-lib.sh is necessary even if they had the same name: the perl
scripts need it to be normalized to a perl truth value, and we also have
to make sure it's exported (we might have gotten it from the
environment, but we might also have gotten it from GIT-BUILD-OPTIONS
directly).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Since v1.7.0-rc2~11 (git-svn: persistent memoization, 2010-01-30),
git-svn has maintained some private per-repository caches in
.git/svn/.caches to avoid refetching and recalculating some
mergeinfo-related information with every "git svn fetch".
These caches use the 'nstore' format from the perl core module
Storable, which can be read and written quickly and was designed for
transfer over the wire (the 'n' stands for 'network'). This format is
endianness-independent and independent of floating-point
representation.
Unfortunately the format is *not* independent of the perl version ---
new perl versions will write files that very old perl cannot read.
Worse, the format is not independent of the size of a perl integer.
So if you toggle perl's use64bitint compile-time option, then using
'git svn fetch' on your old repositories produces errors like this:
Byte order is not compatible at ../../lib/Storable.pm (autosplit
into ../../lib/auto/Storable/_retrieve.al) line 380, at
/usr/share/perl/5.12/Memoize/Storable.pm line 21
That is, upgrading perl to a version that uses use64bitint for the
first time makes git-svn suddenly refuse to fetch in existing
repositories. Removing .git/svn/.caches lets git-svn recover.
It's time to switch to a platform independent serializer backend with
better compatibility guarantees. This patch uses YAML::Any.
Other choices were considered:
- thawing data from Data::Dumper involves "eval". Doing that without
creating a security risk is fussy.
- the JSON API works on scalars in memory and doesn't provide a
standard way to serialize straight to disk.
YAML::Any is reasonably fast and has a pleasant API. In most
backends, LoadFile() reads the entire file into a scalar anyway and
converts it as a second step, but having an interface that allows the
deserialization to happen on the fly without a temporary is still a
comfort.
YAML::Any is not a core perl module, so we take care to use it when
and only when it is available. Installations without that module
should fall back to using Storable with all its quirks, keeping their
cache files in
.git/svn/.caches/*.db
Installations with YAML peacefully coexist by keeping a separate set
of cache files in
.git/svn/.caches/*.yaml.
In most cases, switching between is a one-time thing, so it doesn't
seem worth the complication to migrate existing caches.
The upshot: after this patch, as long as YAML::Any is installed you
can move your git repository between machines with different perl
installations and "git svn fetch" will work fine. If you do not have
YAML::Any, the behavior is unchanged (and in particular does not get
any worse).
Reported-by: Sandro Weiser <sandro.weiser@informatik.tu-chemnitz.de>
Reported-by: Bdale Garbee <bdale@gag.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Eric Wong <normalperson@yhbt.net>
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Jeff King
Jonathan Nieder