packaging: upgrade Debian packaging to build with Python 3

Also drop the explicit "Depends: python" as debhelper will add it.

contrib/packaging/debian/control

@@ -1,54 +1,53 b''
 Source: mercurial
 Section: vcs
 Priority: optional
 Maintainer: Mercurial Developers <[e-mail]>
 Build-Depends:
  debhelper (>= 9),
  dh-python,
  less,
  netbase,
- python-all,
- python-all-dev,
- python-docutils,
+ python3-all,
+ python3-all-dev,
+ python3-docutils,
  unzip,
  zip
 Standards-Version: 3.9.4
-X-Python-Version: >= 2.7
+X-Python3-Version: >= 3.5
 
 Package: mercurial
 Depends:
- python,
  ${shlibs:Depends},
  ${misc:Depends},
- ${python:Depends},
+ ${python3:Depends},
  mercurial-common (= ${source:Version})
 Architecture: any
 Description: fast, easy to use, distributed revision control tool.
  Mercurial is a fast, lightweight Source Control Management system designed
  for efficient handling of very large distributed projects.
  .
  Its features include:
   * O(1) delta-compressed file storage and retrieval scheme
   * Complete cross-indexing of files and changesets for efficient exploration
     of project history
   * Robust SHA1-based integrity checking and append-only storage model
   * Decentralized development model with arbitrary merging between trees
   * Easy-to-use command-line interface
   * Integrated stand-alone web interface
   * Small Python codebase
 
 Package: mercurial-common
 Architecture: all
 Depends:
  ${misc:Depends},
- ${python:Depends},
+ ${python3:Depends},
 Recommends: mercurial (= ${source:Version}), ca-certificates
 Suggests: wish
 Breaks: mercurial (<< ${source:Version})
 Replaces: mercurial (<< 2.6.3)
 Description: easy-to-use, scalable distributed version control system (common files)
  Mercurial is a fast, lightweight Source Control Management system designed
  for efficient handling of very large distributed projects.
  .
  This package contains the architecture independent components of Mercurial,
  and is generally useless without the mercurial package.

contrib/packaging/debian/rules

@@ -1,44 +1,47 b''
 #!/usr/bin/make -f
 # Uncomment this to turn on verbose mode.
 # export DH_VERBOSE=1
 
 CPUS=$(shell cat /proc/cpuinfo | grep -E ^processor | wc -l)
 
+export HGPYTHON3=1
+export PYTHON=python3
+
 %:
-	dh $@ --with python2
+	dh $@ --with python3
 
 override_dh_auto_test:
 	http_proxy='' dh_auto_test -- TESTFLAGS="-j$(CPUS)"
 
-override_dh_python2:
-	dh_python2
+override_dh_python3:
+	dh_python3
 	find debian/mercurial/usr/share -type d -empty -delete
 
 override_dh_install:
-	python$(PYVERS) setup.py install --root "$(CURDIR)"/debian/mercurial --install-layout=deb
+	python3 setup.py install --root "$(CURDIR)"/debian/mercurial --install-layout=deb
 	# chg
 	make -C contrib/chg \
 		DESTDIR="$(CURDIR)"/debian/mercurial \
 		PREFIX=/usr \
 		clean install
 	# remove arch-independent python stuff
 	find "$(CURDIR)"/debian/mercurial/usr/lib \
 		! -name '*.so' ! -type d -delete , \
 		-type d -empty -delete
-	python$(PYVERS) setup.py install --root "$(CURDIR)/debian/mercurial-common" --install-layout=deb
+	python3 setup.py install --root "$(CURDIR)/debian/mercurial-common" --install-layout=deb
 	make install-doc PREFIX="$(CURDIR)"/debian/mercurial-common/usr
 	# remove arch-dependent python stuff
 	find "$(CURDIR)"/debian/mercurial-common/usr/lib \
 		-name '*.so' ! -type d -delete , \
 		-type d -empty -delete
 	cp contrib/hg-ssh "$(CURDIR)"/debian/mercurial-common/usr/bin
 	mkdir -p "$(CURDIR)"/debian/mercurial-common/usr/share/mercurial
 	cp contrib/hgk "$(CURDIR)"/debian/mercurial-common/usr/share/mercurial
 	mkdir -p "$(CURDIR)"/debian/mercurial-common/etc/mercurial/hgrc.d/
 	cp contrib/packaging/debian/*.rc "$(CURDIR)"/debian/mercurial-common/etc/mercurial/hgrc.d/
 	# completions
 	mkdir -p "$(CURDIR)"/debian/mercurial-common/usr/share/bash-completion/completions
 	cp contrib/bash_completion "$(CURDIR)"/debian/mercurial-common/usr/share/bash-completion/completions/hg
 	mkdir -p "$(CURDIR)"/debian/mercurial-common/usr/share/zsh/vendor-completions
 	cp contrib/zsh_completion "$(CURDIR)"/debian/mercurial-common/usr/share/zsh/vendor-completions/_hg
 	rm "$(CURDIR)"/debian/mercurial-common/usr/bin/hg

tests/test-debian-packages.t

@@ -1,32 +1,32 b''
 #require test-repo slow debhelper debdeps
 
   $ . "$TESTDIR/helpers-testrepo.sh"
   $ testrepohgenv
 
 Ensure debuild doesn't run the testsuite, as that could get silly.
   $ DEB_BUILD_OPTIONS=nocheck
   $ export DEB_BUILD_OPTIONS
   $ OUTPUTDIR=`pwd`
   $ export OUTPUTDIR
 
   $ cd "$TESTDIR"/..
   $ make deb > $OUTPUTDIR/build.log 2>&1
   $ cd $OUTPUTDIR
   $ ls *.deb | grep -v 'dbg'
   mercurial-common_*.deb (glob)
   mercurial_*.deb (glob)
 main deb should have .so but no .py
   $ dpkg --contents mercurial_*.deb | egrep '(localrepo|parsers)'
-  * ./usr/lib/python2.7/dist-packages/mercurial/cext/parsers*.so (glob)
+  * ./usr/lib/python3/dist-packages/mercurial/cext/parsers*.so (glob)
 mercurial-common should have py but no .so or pyc
   $ dpkg --contents mercurial-common_*.deb | egrep '(localrepo|parsers.*so)'
-  * ./usr/lib/python2.7/dist-packages/mercurial/localrepo.py (glob)
+  * ./usr/lib/python3/dist-packages/mercurial/localrepo.py (glob)
 zsh completions should be in the common package
   $ dpkg --contents mercurial-common_*.deb | egrep 'zsh.*[^/]$'
   * ./usr/share/zsh/vendor-completions/_hg (glob)
 chg should be installed alongside hg, in the 'mercurial' package
   $ dpkg --contents mercurial_*.deb | egrep 'chg$'
   * ./usr/bin/chg (glob)
 chg should come with a man page
   $ dpkg --contents mercurial_*.deb | egrep 'man.*chg'
   * ./usr/share/man/man1/chg.1.gz (glob)