Merge ubuntu-archive-tools:update-output-helper into ubuntu-archive-tools:main

[Steve Langasek]

This supersedes https://code.launchpad.net/~laney/ubuntu-archive-tools/update-output-helper/+merge/267970 which is so old it predates the migration to git. Much thanks to Laney for the initial implementation of this tool, which I was never entirely happy with in terms of UI but also it was the best available tool for untangling certain large messy transitions.

Then I tried to use it on the current perl transition and it broke because there were too many packages and it overflowed grep-dctrl's pattern matching capabilities.

Significantly rewritten implementation now uses chdist instead of bespoke apt env handling, and uses package pinning to remove the need for digging up specific package versions out of proposed.

This should really go to ubuntu-dev-tools instead of ubuntu-archive-tools, but since this was the target of the original MP I'm parking it here for now so that it doesn't get lost!

[Steve Langasek (vorlon)]

Oh also I have no idea where the choice of ~/.cache/brapt originally came from, so somebody please poke holes in this and suggest something better

[Steve Langasek (vorlon)]

Well it seems this implementation doesn't actually *work*, so I'm tagging Julian to see if maybe he can figure out how I'm managing to drive chdist+apt+preferences wrong.

[Steve Langasek (vorlon)]

How I'm trying to use it:

$ update-output-helper $(wcat https://ubuntu-archive-team.ubuntu.com/proposed-migration/update_output.txt | sed -n -e'/[[:space:]]perl[[:space:]]/ { s/^trying: //p }' | head -n1)
$ chdist -d "/home/vorlon/.cache/brapt" apt u-a-h --dry-run install accerciser

and this succeeds where, based on update_output, I expect it to fail.

[Steve Langasek (vorlon)]

getting useful output with the latest commit so maybe this is fixed now. apt-cache(8) doesn't explain what order the records will be shown in, maybe this is undefined.

[Julian Andres Klode (juliank)]

apt-cache showsrc --only-source is really bad if you have a binary name it becomes a lot more reliable, but even then it doesn't support `package/newest` sadly, or any of the / or = modifiers. I think with --only-source it literally just iterates over all Sources files in order.

But it should show you all versions, and you can use `sort-dctrl -k Version:v` from dctrl-tools to sort them by version.

diff --git a/update-output-helper b/update-output-helper
new file mode 100755
index 0000000..4fd2e1a
--- /dev/null
+++ b/update-output-helper
@@ -0,0 +1,129 @@
+#!/bin/bash
+
+# Author: Iain Lane <[e-mail]>,
+#         Steve Langasek <[e-mail]>
+# Copyright: 2015-2024 Canonical Ltd
+# License: GPLv3
+
+# Run me like this:
+# Download all the Packages files:
+# * update-output-helper -u
+# Create a worldview that britney is trying to mutate us to
+# * update-output-helper package package2 ...
+# outputs a chdist apt-get commandline to use
+# Then call apt with this world view
+# * <apt-get command> --dry-run install <some uninstallable package>
+# and you can drill down as normal to find which package(s) need fixing
+
+# maybe you want to do something like this:
+# $ update-output-helper $(wget -O - -q \
+#	https://ubuntu-archive-team.ubuntu.com/proposed-migration/update_output.txt \
+#	| sed -n -e'/[[:space:]]perl[[:space:]]/ { s/^trying: //p }' | head -n1)
+
+
+set -e
+
+GETOPT=$(getopt --options uhf: --long update,help -n "${0}" -- "$@")
+
+eval set -- "${GETOPT}"
+
+ARCH=${ARCH:-$(dpkg-architecture -qDEB_HOST_ARCH)}
+CACHEDIR="${XDG_CACHE_HOME:-$HOME/.cache}/brapt"
+APTDIR="$CACHEDIR"/u-a-h
+RELEASE=$(ubuntu-distro-info --devel)
+PREFERENCES="${APTDIR}"/etc/apt/preferences.d/proposed-migration
+
+[ ! -d "${CACHEDIR}" ] && mkdir -p "${CACHEDIR}"
+
+update() {
+    case ${ARCH} in
+        i386|amd64)
+            local MIRROR="http://archive.ubuntu.com/ubuntu"
+            ;;
+        *)
+            local MIRROR="http://ports.ubuntu.com"
+            ;;
+    esac
+    # wipe it out in case the existing chdist is for a stale distribution
+    rm -rf "$APTDIR"
+
+    chdist -d "$CACHEDIR" -a "$ARCH" create u-a-h $MIRROR $RELEASE \
+    	"main universe multiverse restricted"
+
+    # becomes invalid when chdist switches to deb822
+    sed -e"s/\b$RELEASE\b/&-proposed/" "$APTDIR"/etc/apt/sources.list \
+		>> "$APTDIR"/etc/apt/sources.list
+
+    chdist -d "$CACHEDIR" apt-get u-a-h update
+
+}
+
+while true; do
+    case "$1" in
+        -u|--update)
+            update
+            shift
+            ;;
+        -h|--help)
+            echo "Usage: $0 [-u] package [...]"
+            shift
+            ;;
+        -f)
+            input_file="$2"
+            shift 2
+            ;;
+        --)
+            shift
+            break
+            ;;
+        *)
+            echo "Error"
+            exit 1;
+            ;;
+    esac
+done
+
+if [ $# -eq 0 ] && [ -z "$input_file" ]; then
+    exit 0
+fi
+
+cat > "$PREFERENCES" <<EOF
+Package: *
+Pin: release a=*-proposed
+Pin-Priority: -1
+
+EOF
+
+# inner loop.  Can be called one of two ways, with lines from an input file
+# or commandline arg list.
+package_loop() {
+	PKG=$1
+
+	cat >> "$PREFERENCES" <<EOF
+Package: src:$PKG
+Pin: release a=*-proposed
+Pin-Priority: 990
+
+Package: src:$PKG
+Pin: release a=$RELEASE
+Pin-Priority: -1
+
+EOF
+
+}
+
+
+while [ $# -gt 0 ]; do
+	package_loop $1
+	shift
+done
+
+if [ -n "$input_file" ]; then
+	while read pkg; do
+		package_loop $pkg
+	done < "$input_file"
+
+fi
+chdist -d "$CACHEDIR" apt-get u-a-h update
+
+echo "chdist -d \"$CACHEDIR\" apt u-a-h --dry-run install <some broken package> ..."