* pbuilder-satisfydepends-experimental, Makefile: alternate

implementation of pbuilder-satisfydepends which supports pulling
build-deps with a version on the apt-get command-line; this is derived
from pbuilder-satisfydepends with the following changes:
- Add and use new package_versions() and candidate_version() helpers;
  the former returns all versions of a package available via APT, the
  later APT's candidate version.
- For versionned build-deps, when building the "apt-get install"
  command, try APT's candidate version or all available versions
  available from APT in ascending order (the reverse order of
  apt-cache's output); checkbuilddep_versiondeps() isn't used for this
  part of the process anymore, but it is still used to honor
  build-conflicts.
- Recover from APT errors caused by unsufficient dependencies
  ("libfoo-dev Depends: bar but baz is to be installed") and missing
  dependencies libfoo-dev Depends: bar but it is not going to be
  installed", or simply "libfoo-dev Depends: bar"); this permits
  simply listing build-deps when uploading to experimental; achieved
  by moving the version matching logic in the new
  versioneddep_to_aptcmd() helper.
* pbuilderrc, pbuilderrc.5: document the availability of the alternate
implementation.

6 files changed, 400 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index 676182e..73f84b3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -14,6 +14,28 @@
 	* pdebuild: pass --pbuildersatisfydepends to pdebuild-internal.
 	* pbuilder-modules, pdebuild.1: document --pbuildersatisfydepends.
 	* pbuilder-satisfydepends: drop an useless invocation of awk.
+	* pbuilder-satisfydepends-experimental, Makefile: alternate
+	implementation of pbuilder-satisfydepends which supports pulling
+	build-deps with a version on the apt-get command-line; this is derived
+	from pbuilder-satisfydepends with the following changes:
+	- Add and use new package_versions() and candidate_version() helpers;
+	  the former returns all versions of a package available via APT, the
+	  later APT's candidate version.
+	- For versionned build-deps, when building the "apt-get install"
+	  command, try APT's candidate version or all available versions
+	  available from APT in ascending order (the reverse order of
+	  apt-cache's output); checkbuilddep_versiondeps() isn't used for this
+	  part of the process anymore, but it is still used to honor
+	  build-conflicts.
+	- Recover from APT errors caused by unsufficient dependencies
+	  ("libfoo-dev Depends: bar but baz is to be installed") and missing
+	  dependencies libfoo-dev Depends: bar but it is not going to be
+	  installed", or simply "libfoo-dev Depends: bar"); this permits
+	  simply listing build-deps when uploading to experimental; achieved
+	  by moving the version matching logic in the new
+	  versioneddep_to_aptcmd() helper.
+	* pbuilderrc, pbuilderrc.5: document the availability of the alternate
+	implementation.
 
 2006-11-03  Loic Minier <lool@dooz.org>
 
diff --git a/Makefile b/Makefile
index a301940..7831be7 100644
--- a/Makefile
+++ b/Makefile
@@ -15,6 +15,7 @@ SHELLCODES=pbuilder-buildpackage \
 	pbuilder-modules \
 	pbuilder-runhooks \
 	pbuilder-satisfydepends \
+	pbuilder-satisfydepends-experimental \
 	pbuilder-updatebuildenv \
 	pbuilder-user-mode-linux \
 	pbuilder \
@@ -70,6 +71,7 @@ install:
 	$(INSTALL_EXECUTABLE) pdebuild-user-mode-linux $(DESTDIR)/usr/bin
 	$(INSTALL_EXECUTABLE) debuild-pbuilder $(DESTDIR)/usr/bin
 	$(INSTALL_EXECUTABLE) pbuilder-satisfydepends $(DESTDIR)/usr/lib/pbuilder/
+	$(INSTALL_EXECUTABLE) pbuilder-satisfydepends-experimental $(DESTDIR)/usr/lib/pbuilder/
 	$(INSTALL_EXECUTABLE) pdebuild-internal $(DESTDIR)/usr/lib/pbuilder/
 	$(INSTALL_FILE) pbuilderrc $(DESTDIR)/etc
 	$(INSTALL_FILE) pbuilderrc $(DESTDIR)/usr/share/pbuilder
diff --git a/debian/changelog b/debian/changelog
index 2a2eb9a..3027886 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -17,6 +17,9 @@ pbuilder (0.161) UNRELEASED; urgency=low
   * New PBUILDERSATISFYDEPENDSCMD config option and --pbuildersatisfydepends
     override flag to set the command to run to satisfy build dependencies;
     default to the /usr/lib/pbuilder/pbuilder-satisfydepends helper.
+  * New experimental implementation of PBUILDERSATISFYDEPENDSCMD,
+    pbuilder-satisfydepends-experimental, which might help building packages
+    targetted at experimental.
 
  -- Loic Minier <lool@dooz.org>  Mon,  6 Nov 2006 19:38:36 +0100
 
diff --git a/pbuilder-satisfydepends-experimental b/pbuilder-satisfydepends-experimental
new file mode 100755
index 0000000..633acf7
--- /dev/null
+++ b/pbuilder-satisfydepends-experimental
@@ -0,0 +1,365 @@
+#!/bin/bash
+#   pbuilder -- personal Debian package builder
+#   Copyright (C) 2001,2002,2003,2005-2006 Junichi Uekawa
+#
+#   This program is free software; you can redistribute it and/or modify
+#   it under the terms of the GNU General Public License as published by
+#   the Free Software Foundation; either version 2 of the License, or
+#   (at your option) any later version.
+#
+#   This program is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU General Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License
+#   along with this program; if not, write to the Free Software
+#   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+
+#
+# module to satisfy dependency.
+
+set -e
+
+function package_versions() {
+	local PACKAGE="$1"
+	( $CHROOTEXEC /usr/bin/apt-cache show "$PACKAGE" ) | sed -n 's/^Version: \(.*\)$/\1/p'
+}
+
+function candidate_version() {
+	local PACKAGE="$1"
+	LC_ALL=C $CHROOTEXEC apt-cache policy "$PACKAGE" | sed -n 's/ *Candidate: *\(.*\)/\1/p'
+}
+
+function checkbuilddep_versiondeps () {
+    local PACKAGE="$1"
+    local COMPARESTRING="$2"
+    local DEPSVERSION="$3"
+    local PACKAGEVERSIONS=$( package_versions "$PACKAGE" | xargs)
+    # no versioned provides.
+    if [ "${FORCEVERSION}" = "yes" ]; then
+	return 0;
+    fi
+    for PACKAGEVERSION in $PACKAGEVERSIONS ; do
+      if dpkg --compare-versions "$PACKAGEVERSION" "$COMPARESTRING" "$DEPSVERSION"; then
+	# satisfies depends
+	return 0;
+      fi
+    done
+    echo "      Tried versions: $PACKAGEVERSIONS"
+    # cannot satisfy depends
+    return 1;
+}
+
+function expand_arch () {
+    local ARCH="$1"
+    local EXPANDED_ARCH
+    
+    # just keep the original behavior.
+    echo "$ARCH"
+    return
+
+    # the following may be used if dpkg change is set to stone.
+    if echo "$ARCH" | grep "-" > /dev/null; then
+        EXPANDED_ARCH=$ARCH
+    else
+        EXPANDED_ARCH="linux-$ARCH"
+    fi
+    local WC1=$(echo $EXPANDED_ARCH | sed 's/^[^-]*/any/')
+    local WC2=$(echo $EXPANDED_ARCH | sed 's/[^-]*$/any/')
+    echo "$ARCH\\|$EXPANDED_ARCH\\|$WC1\\|$WC2"
+}
+
+function checkbuilddep_archdeps () {
+    # returns FALSE on INSTALL
+    local INSTALLPKG="$1"
+    local ARCH="$2"
+    if echo "$INSTALLPKG" | sed 's/.*\(\[.*\]\)/\1/' | grep "[[/][!]\($(expand_arch $ARCH)\)[]/]" > /dev/null; then
+	# if !$ARCH exists in there, ERROR.
+	return 0;
+    fi
+    if ! echo "$INSTALLPKG" | sed 's/.*\(\[.*\]\)/\1/' | grep "[!]" > /dev/null; then
+	if ! echo "$INSTALLPKG" | sed 's/.*\(\[.*\]\)/\1/' | grep "[[/]\($(expand_arch $ARCH)\)[]/]" > /dev/null; then
+	# if $ARCH does not exist, ERROR.
+	    return 0;
+	fi
+    fi
+    return 1;
+}
+
+function checkbuilddep_provides () {
+    local PACKAGENAME="$1"
+    # PROVIDED needs to be used outside of this function.
+    PROVIDED=$($CHROOTEXEC /usr/bin/apt-cache showpkg $PACKAGENAME | awk '{p=0}/^Reverse Provides:/,/^$/{p=1}{if(p && ($0 !~ "Reverse Provides:")){PACKAGE=$1}} END{print PACKAGE}')
+}
+
+# returns either "package=version", to append to an apt-get install line, or
+# package
+function versioneddep_to_aptcmd () {
+	local INSTALLPKG="$1"
+
+	local PACKAGE
+	local PACKAGE_WITHVERSION
+	local PACKAGEVERSIONS
+	local CANDIDATE_VERSION
+	local COMPARESTRING
+	local DEPSVERSION
+
+	PACKAGE="$(echo "$INSTALLPKG" | sed -e 's/^[/]*//' -e 's/[[/(].*//')"
+	PACKAGE_WITHVERSION="$PACKAGE"
+
+	# if not versionned, we skip directly to outputting $PACKAGE
+	if echo "$INSTALLPKG" | grep '[(]' > /dev/null; then
+	    # package versions returned by APT, in reversed order
+	    PACKAGEVERSIONS="$( package_versions "$PACKAGE" | tac | xargs )"
+	    CANDIDATE_VERSION="$( candidate_version "$PACKAGE" )"
+
+	    # try the candidate version, then all available versions (asc)
+	    for VERSION in $CANDIDATE_VERSION $PACKAGEVERSIONS; do
+		COMPARESTRING=$(echo "$INSTALLPKG" | tr "/" " " | sed 's/^.*([ ]*\(<<\|<=\|>=\|=\|<\|>>\|>\)[ ]*\(.*\)).*$/\1/')
+		DEPSVERSION="$(echo "$INSTALLPKG" | tr "/" " " | sed 's/^.*([ ]*\(<<\|<=\|>=\|=\|<\|>>\|>\)[ ]*\(.*\)).*$/\2/')"
+		if dpkg --compare-versions "$VERSION" "$COMPARESTRING" "$DEPSVERSION"; then
+		    if [ $VERSION != $CANDIDATE_VERSION ]; then
+			PACKAGE_WITHVERSION="$PACKAGE=$VERSION"
+		    fi
+		    break;
+		fi
+	    done
+	fi
+
+	echo "$PACKAGE_WITHVERSION"
+}
+
+function checkbuilddep_internal () {
+# Use this function to fulfill the dependency (almost)
+
+    local ARCH=$(dpkg-architecture -qDEB_HOST_ARCH)
+    local INSTALLPKG
+    local INSTALLPKGLIST
+    local INSTALLPKGMULTI
+    local CURRENTREALPKGNAME
+    local SATISFIED
+    local PACKAGEVERSIONS
+    local CANDIDATE_VERSION
+    echo " -> Attempting to parse the build-deps $Id$"
+    for INSTALLPKGMULTI in $(cat ${DEBIAN_CONTROL} | \
+	awk '
+BEGIN{source=1} 
+/^$/      {source=0} 
+/^Source:/      {source=1} 
+/^[^ ]*:/ {p=0} 
+tolower($0) ~ /^'"${BD_REGEXP}"':/   {p=1} 
+{if(p && source) {print $0}}'  | \
+	sed 's/^[^: ]*://' | \
+	tr " " "/" | \
+	awk 'BEGIN{RS=","} {print}'); do
+      echo " -> Considering build-dep$(echo "$INSTALLPKGMULTI" | tr "/" " " )"
+      SATISFIED="no"
+      for INSTALLPKG in $(echo "$INSTALLPKGMULTI" | \
+	  awk 'BEGIN{RS="|"} {print}'); do
+	CURRENTREALPKGNAME=$(echo "$INSTALLPKG" | sed -e 's/^[/]*//' -e 's/[[/(].*//')
+	if echo "$INSTALLPKG" | grep '\[' > /dev/null ; then
+	    if checkbuilddep_archdeps "$INSTALLPKG" "$ARCH"; then
+		SATISFIED="yes"
+		echo "   -> This package is not for this architecture"
+		continue;
+	    fi
+	fi
+
+	CURRENT_APT_COMMAND="$(versioneddep_to_aptcmd "$INSTALLPKG")"
+
+	while [ "$SATISFIED" = "no" ]; do
+	    echo "   -> Trying to add ${CURRENT_APT_COMMAND}"
+	    if APT_OUTPUT="$( exec 2>&1; LC_ALL=C $CHROOTEXEC /usr/bin/apt-get -s install ${INSTALLPKGLIST} ${CURRENT_APT_COMMAND} )"; then
+		# success, we're done
+		SATISFIED="yes"
+		INSTALLPKGLIST="${INSTALLPKGLIST} ${CURRENT_APT_COMMAND}"
+		break
+	    fi
+	    # try to parse APT's output to recognize lines such as:
+	    #   libfoo-dev: Depends: bar (>= xyz) but www is to be installed
+	    DEP_INSTALLPKG="$(echo "$APT_OUTPUT" | \
+		sed -n \
+		    -e "s/^ *.*: *Depends: *\(.*\) but.*is to be installed\$/\\1/p" \
+		    -e "s/^ *.*: *Depends: *\(.*\) but it is not going to be installed\$/\\1/p" \
+		    -e "s/^ *.*: *Depends: *\(.*\)\$/\\1/p" | \
+		head -1 | \
+		tr " " "/")"
+	    APT_ADD_COMMAND="$(versioneddep_to_aptcmd "$DEP_INSTALLPKG")"
+	    if echo "$CURRENT_APT_COMMAND" | grep -q "$APT_ADD_COMMAND"; then
+		# loop detected, give up with real packages
+		echo "   -> Loop detected, last APT error was: ======"
+		echo "$APT_OUTPUT"
+		echo "   -> ========================================="
+		echo "   -> (not adding $APT_ADD_COMMAND to $CURRENT_APT_COMMAND)"
+		break
+	    fi
+	    CURRENT_APT_COMMAND="$CURRENT_APT_COMMAND $APT_ADD_COMMAND"
+	done
+	if [ "$SATISFIED" = "yes" ]; then
+	    break;
+	fi
+
+	echo "       -> Cannot install ${CURRENT_APT_COMMAND}; apt errors follow:"
+	if $CHROOTEXEC /usr/bin/apt-get -s install ${INSTALLPKGLIST} "${CURRENT_APT_COMMAND}"; then
+	    :
+	fi
+	# package could not be found. -- looking for alternative.
+	PROVIDED=""
+	checkbuilddep_provides "${CURRENTREALPKGNAME}"
+	if [ -n "$PROVIDED" ]; then
+	    # something provides this package
+	    echo "     -> Considering $PROVIDED to satisfy the dependency "
+	    if $CHROOTEXEC /usr/bin/apt-get -s install ${INSTALLPKGLIST} ${PROVIDED} >& /dev/null; then
+		SATISFIED="yes";
+		INSTALLPKGLIST="${INSTALLPKGLIST} ${PROVIDED}"
+	    else
+		# show the error for diagnostic purposes
+		echo "       -> Cannot install $PROVIDED; apt errors follow:"
+		if $CHROOTEXEC /usr/bin/apt-get -s install ${INSTALLPKGLIST} ${PROVIDED}; then
+		    :
+		fi
+	    fi
+	fi
+	if [ "$SATISFIED" = "yes" ]; then
+	    break;
+	fi
+      done;
+      if [ "$SATISFIED" = "no" ]; then
+	  echo "E: Could not satisfy build-dependency." >&2
+	  if [ "$CONTINUE_FAIL" != "yes" ]; then
+	      exit 2
+	  fi
+      fi
+    done;
+    
+    # now actually install the packages
+    echo " -> Installing ${INSTALLPKGLIST}"
+    if ! $CHROOTEXEC apt-get -y --force-yes install ${INSTALLPKGLIST}; then
+	echo " -> Trying to fix apt error"
+	# Work around an apt bug which causes configure to fail.
+	if $CHROOTEXEC dpkg --configure --pending && $CHROOTEXEC apt-get -y --force-yes install ${INSTALLPKGLIST}; then
+	    echo " -> Apt bug workaround succeeded"
+	elif [ "$CONTINUE_FAIL" != "yes" ]; then
+	    echo "E: Unrecoverable error installing build-dependencies." >&2
+	    exit 1
+	fi
+    fi
+
+    # start processing build-conflicts.
+    for INSTALLPKG in $(cat "${DEBIAN_CONTROL}" | \
+	awk 'BEGIN{source=1} 
+/^$/      {source=0} 
+/^Source:/      {source=1} 
+/^[^ ]*:/{p=0} 
+tolower($0) ~ /^'"${BC_REGEXP}"':/   {p=1} 
+{if(p && source) {print $0}}'  | \
+	sed 's/^[^: ]*://' | \
+	tr " " "/" | \
+	awk 'BEGIN{RS=","} {print}'); do
+      CURRENTREALPKGNAME=$(echo "$INSTALLPKG" | sed -e 's/^[/]*//' -e 's/[[/(].*//')
+      echo " -> Considering ${CURRENTREALPKGNAME}"
+      
+      if echo "$INSTALLPKG" | grep '\[' > /dev/null ; then
+	  # this package has arch-conflicts.
+	  if checkbuilddep_archdeps "$INSTALLPKG" "$ARCH"; then
+	      echo "I: Ignoring other-arch"
+	      continue;
+	  fi
+      fi
+      if echo "$INSTALLPKG" | grep '[(]' > /dev/null ; then
+	  # this package has version-conflicts
+	  if ! checkbuilddep_versiondeps ${CURRENTREALPKGNAME} \
+		$(echo "$INSTALLPKG" | tr "/" " " | sed 's/^.*([ ]*\(<<\|<=\|>=\|=\|<\|>>\|>\)[ ]*\(.*\)).*$/\1/') \
+		$(echo "$INSTALLPKG" | tr "/" " " | sed 's/^.*([ ]*\(<<\|<=\|>=\|=\|<\|>>\|>\)[ ]*\(.*\)).*$/\2/'); then
+	      echo "I: Satisfies version, not trying"
+	      continue;
+	  fi
+      fi
+
+      # if package exists, remove it.
+      if $CHROOTEXEC /usr/bin/dpkg -s $(echo "$INSTALLPKG" | tr "/" " " | awk '{print $1}') 2>&1 | grep ^Package: > /dev/null; then
+	  if ! $CHROOTEXEC /usr/bin/apt-get -y remove ${CURRENTREALPKGNAME} ; then
+	      echo "E: Could not satisfy build-conflicts" >&2
+	      exit 1
+	  fi
+      else
+	  echo "I: ${CURRENTREALPKGNAME} package is not installed, no need to remove"
+      fi
+    done
+    echo " -> Finished parsing the build-deps"
+}
+
+
+function print_help () {
+    # print out help message
+    cat <<EOF
+pbuilder-satisfydepends -- satisfy dependencies
+Copyright 2002-2006  Junichi Uekawa <dancer@debian.org>
+
+--help:        give help
+--control:     specify control file (debian/control, *.dsc)
+--chroot:      operate inside chroot
+--binary-all:  include binary-all
+--binary-arch: include binary-arch only
+--echo:        echo mode, do nothing. (--force-version required for most operation)
+--force-version: skip version check.
+--continue-fail: continue even when failed.
+
+EOF
+}
+
+
+DEBIAN_CONTROL=debian/control
+CHROOTEXEC=""
+BD_REGEXP="build-(depends|depends-indep)"
+BC_REGEXP="build-(conflicts|conflicts-indep)"
+FORCEVERSION=""
+CONTINUE_FAIL="no"
+
+
+while [ -n "$1" ]; do
+    case "$1" in
+	--control|-c)
+	    DEBIAN_CONTROL="$2"
+	    shift; shift
+	    ;;
+	--chroot)
+	    CHROOTEXEC="chroot $2 "
+	    shift; shift
+	    ;;
+	--internal-chrootexec)
+	    CHROOTEXEC="$2"
+	    shift; shift 
+	    ;;
+	--binary-all)
+	    BD_REGEXP='build-(depends|depends-indep)'
+	    BC_REGEXP='build-(conflicts|conflicts-indep)'
+	    shift
+	    ;;
+	--binary-arch)
+	    BD_REGEXP='build-depends'
+	    BC_REGEXP='build-conflicts'
+	    shift
+	    ;;
+	--echo)
+	    CHROOTEXEC="echo $CHROOTEXEC"
+	    shift
+	    ;;
+	--continue-fail)
+	    CONTINUE_FAIL="yes"
+	    shift
+	    ;;
+	--force-version)
+	    FORCEVERSION="yes"
+	    shift;
+	    ;;
+	--help|-h|*)
+	    print_help
+	    exit 1
+	    ;;
+    esac
+done
+
+
+checkbuilddep_internal
diff --git a/pbuilderrc b/pbuilderrc
index 71db7a3..196a0c0 100755
--- a/pbuilderrc
+++ b/pbuilderrc
@@ -35,7 +35,10 @@ BUILDSOURCEROOTCMD="fakeroot"
 PBUILDERROOTCMD="sudo"
 
 # command to satisfy build-dependencies; the default is an internal shell
-# implementation which is relatively slow
+# implementation which is relatively slow; there's an alternate experimental
+# implementation, "pbuilder-satisfydepends-experimental", which might be useful
+# to pull packages from experimental or from repositories with a low APT Pin
+# Priority
 PBUILDERSATISFYDEPENDSCMD="/usr/lib/pbuilder/pbuilder-satisfydepends"
 
 #default is to build everything. Passed on to dpkg-buildpackage
diff --git a/pbuilderrc.5 b/pbuilderrc.5
index 4780ff4..f65f768 100644
--- a/pbuilderrc.5
+++ b/pbuilderrc.5
@@ -216,7 +216,10 @@ in
 .BI "PBUILDERSATISFYDEPENDSCMD=" "/usr/lib/pbuilder/pbuilder-satisfydepends"
 
 This option is used by various parts of pbuilder to satisfy (i.e. install) the
-build-dependencies of a package.
+build-dependencies of a package.  There is an alternate experimental
+implementation, "pbuilder-satisfydepends-experimental", which might be useful
+to pull packages from experimental or from repositories with a low APT Pin
+Priority.
 
 .TP
 .BI "BUILDUSERID=" "1234"