view contrib/buildrpm @ 27142:060f83d219b9

extensions: refuse to load extensions if minimum hg version not met

As the author of several 3rd party extensions, I frequently see bug
reports from users attempting to run my extension with an old version
of Mercurial that I no longer support in my extension. Oftentimes, the
extension will import just fine. But as soon as we run extsetup(),
reposetup(), or get into the guts of a wrapped function, we encounter
an exception and abort. Today, Mercurial will print a message about
extensions that don't have a "testedwith" declaring explicit
compatibility with the current version.

The existing mechanism is a good start. But it isn't as robust as I
would like. Specifically, Mercurial assumes compatibility by default.
This means extension authors must perform compatibility checking in
their extsetup() or we wait and see if we encounter an abort at
runtime. And, compatibility checking can involve a lot of code and
lots of error checking. It's a lot of effort for extension authors.

Oftentimes, extension authors know which versions of Mercurial there
extension works on and more importantly where it is broken.

This patch introduces a magic "minimumhgversion" attribute in
extensions. When found, the extension loading mechanism will compare
the declared version against the current Mercurial version. If the
extension explicitly states we require a newer Mercurial version, a
warning is printed and the extension isn't loaded beyond importing
the Python module. This causes a graceful failure while alerting
the user of the compatibility issue.

I would be receptive to the idea of making the failure more fatal.
However, care would need to be taken to not criple every hg command.
e.g. the user may use `hg config` to fix the hgrc and if we aborted
trying to run that, the user would effectively be locked out of `hg`!

A potential future improvement to this functionality would be to catch
ImportError for the extension/module and parse the source code for
"minimumhgversion = 'XXX'" and do similar checking. This way we could
give more information about why the extension failed to load.

#!/bin/sh -e
#
# Build a Mercurial RPM from the current repo
#
# Tested on
# - Fedora 20
# - CentOS 5
# - centOS 6

. $(dirname $0)/packagelib.sh

BUILD=1
RPMBUILDDIR="$PWD/rpmbuild"
while [ "$1" ]; do
    case "$1" in
    --prepare )
        shift
        BUILD=
        ;;
    --withpython | --with-python)
        shift
        PYTHONVER=2.7.10
        PYTHONMD5=d7547558fd673bd9d38e2108c6b42521
        ;;
    --rpmbuilddir )
        shift
        RPMBUILDDIR="$1"
        shift
        ;;
    * )
        echo "Invalid parameter $1!" 1>&2
        exit 1
        ;;
    esac
done

cd "`dirname $0`/.."

specfile=$PWD/contrib/mercurial.spec
if [ ! -f $specfile ]; then
    echo "Cannot find $specfile!" 1>&2
    exit 1
fi

if [ ! -d .hg ]; then
    echo 'You are not inside a Mercurial repository!' 1>&2
    exit 1
fi

gethgversion

# TODO: handle distance/node set, and type set

if [ -z "$type" ] ; then
   release=1
else
    release=0.9_$type
fi

if [ -n "$distance" ] ; then
    release=$release+$distance_$node
fi

if [ "$PYTHONVER" ]; then
    release=$release+$PYTHONVER
    RPMPYTHONVER=$PYTHONVER
else
    RPMPYTHONVER=%{nil}
fi

mkdir -p $RPMBUILDDIR/SOURCES
$HG archive -t tgz $RPMBUILDDIR/SOURCES/mercurial-$version-$release.tar.gz
if [ "$PYTHONVER" ]; then
(
    mkdir -p build
    cd build
    PYTHON_SRCFILE=Python-$PYTHONVER.tgz
    [ -f $PYTHON_SRCFILE ] || curl -Lo $PYTHON_SRCFILE http://www.python.org/ftp/python/$PYTHONVER/$PYTHON_SRCFILE
    if [ "$PYTHONMD5" ]; then
        echo "$PYTHONMD5 $PYTHON_SRCFILE" | md5sum -w -c
    fi
    ln -f $PYTHON_SRCFILE $RPMBUILDDIR/SOURCES/$PYTHON_SRCFILE

    DOCUTILSVER=`sed -ne "s/^%global docutilsname docutils-//p" $specfile`
    DOCUTILS_SRCFILE=docutils-$DOCUTILSVER.tar.gz
    [ -f $DOCUTILS_SRCFILE ] || curl -Lo $DOCUTILS_SRCFILE http://downloads.sourceforge.net/project/docutils/docutils/$DOCUTILSVER/$DOCUTILS_SRCFILE
    DOCUTILSMD5=`sed -ne "s/^%global docutilsmd5 //p" $specfile`
    if [ "$DOCUTILSMD5" ]; then
        echo "$DOCUTILSMD5 $DOCUTILS_SRCFILE" | md5sum -w -c
    fi
    ln -f $DOCUTILS_SRCFILE $RPMBUILDDIR/SOURCES/$DOCUTILS_SRCFILE
)
fi

mkdir -p $RPMBUILDDIR/SPECS
rpmspec=$RPMBUILDDIR/SPECS/mercurial.spec

sed -e "s,^Version:.*,Version: $version," \
    -e "s,^Release:.*,Release: $release," \
    $specfile > $rpmspec

echo >> $rpmspec
echo "%changelog" >> $rpmspec

if echo $version | grep '+' > /dev/null 2>&1; then
    latesttag="`echo $version | sed -e 's/+.*//'`"
    $HG log -r .:"$latesttag" -fM \
        --template '{date|hgdate}\t{author}\t{desc|firstline}\n' | python -c '
import sys, time

def datestr(date, format):
    return time.strftime(format, time.gmtime(float(date[0]) - date[1]))

changelog = []
for l in sys.stdin.readlines():
    tok = l.split("\t")
    hgdate = tuple(int(v) for v in tok[0].split())
    changelog.append((datestr(hgdate, "%F"), tok[1], hgdate, tok[2]))
prevtitle = ""
for l in sorted(changelog, reverse=True):
    title = "* %s %s" % (datestr(l[2], "%a %b %d %Y"), l[1])
    if prevtitle != title:
        prevtitle = title
        print
        print title
    print "- %s" % l[3].strip()
' >> $rpmspec

else

    $HG log \
         --template '{date|hgdate}\t{author}\t{desc|firstline}\n' \
         .hgtags | python -c '
import sys, time

def datestr(date, format):
    return time.strftime(format, time.gmtime(float(date[0]) - date[1]))

for l in sys.stdin.readlines():
    tok = l.split("\t")
    hgdate = tuple(int(v) for v in tok[0].split())
    print "* %s %s\n- %s" % (datestr(hgdate, "%a %b %d %Y"), tok[1], tok[2])
' >> $rpmspec

fi

sed -i \
    -e "s/^%define withpython.*$/%define withpython $RPMPYTHONVER/" \
    $rpmspec

if [ "$BUILD" ]; then
    rpmbuild --define "_topdir $RPMBUILDDIR" -ba $rpmspec --clean
    if [ $? = 0 ]; then
        echo
        echo "Built packages for $version-$release:"
        find $RPMBUILDDIR/*RPMS/ -type f -newer $rpmspec
    fi
else
    echo "Prepared sources for $version-$release $rpmspec are in $RPMBUILDDIR/SOURCES/ - use like:"
    echo "rpmbuild --define '_topdir $RPMBUILDDIR' -ba $rpmspec --clean"
fi