crosvm.updateScript: stop trying manifest-versions

manifest-versions never seems to contain the release build any more,
so we can't use it to find the version of crosvm being served to CrOS
devices.

Instead, I've changed the update script to take the latest version of
the appropriate crosvm Chrome OS release branch.  This is the branch
that gets served.  Every release, it is branched off from the
"chromeos" branch (which is the one that passes Chrome OS QA), and
then collects any critical fixes over the lifetime of the release.

With this change, I've introduced a new, simplified versioning
scheme, e.g. 100.0.  The tip build is always 1:1 with the Chrome
version, so having both of those is redundant.  The other number is
the number of commits that have been added to the release branch after
branching from the chromeos branch, so that the number will go up if
we update to include a new commit from the same release.

2 files changed, 11 insertions, 30 deletions

diff --git a/pkgs/applications/virtualization/crosvm/default.nix b/pkgs/applications/virtualization/crosvm/default.nix
index 68ba3b56e2caa..d71443c9b3843 100644
--- a/pkgs/applications/virtualization/crosvm/default.nix
+++ b/pkgs/applications/virtualization/crosvm/default.nix
@@ -55,7 +55,7 @@ in
 
     meta = with lib; {
       description = "A secure virtual machine monitor for KVM";
-      homepage = "https://chromium.googlesource.com/chromiumos/platform/crosvm/";
+      homepage = "https://chromium.googlesource.com/crosvm/crosvm/";
       maintainers = with maintainers; [ qyliss ];
       license = licenses.bsd3;
       platforms = [ "aarch64-linux" "x86_64-linux" ];
diff --git a/pkgs/applications/virtualization/crosvm/update.py b/pkgs/applications/virtualization/crosvm/update.py
index 24185b3278126..be9de54031b2e 100755
--- a/pkgs/applications/virtualization/crosvm/update.py
+++ b/pkgs/applications/virtualization/crosvm/update.py
@@ -1,8 +1,7 @@
 #! /usr/bin/env nix-shell
-#! nix-shell -p nix-prefetch-git "python3.withPackages (ps: with ps; [ lxml ])"
+#! nix-shell -p nix-prefetch-git python3
 #! nix-shell -i python
 
-import base64
 import csv
 import json
 import re
@@ -13,8 +12,6 @@ from urllib.request import urlopen
 
 git_path = 'chromiumos/platform/crosvm'
 git_root = 'https://chromium.googlesource.com/'
-manifest_versions = f'{git_root}chromiumos/manifest-versions'
-buildspecs_url = f'{manifest_versions}/+/refs/heads/master/full/buildspecs/'
 
 # CrOS version numbers look like this:
 # [<chrome-major-version>.]<tip-build>.<branch-build>.<branch-branch-build>
@@ -39,38 +36,22 @@ with urlopen('https://chromiumdash.appspot.com/cros/download_serving_builds_csv?
         platform_version = max(platform_version, this_platform_version)
 
 chrome_major_version = chrome_version[0]
-chromeos_tip_build = str(platform_version[0])
+chromeos_tip_build = platform_version[0]
+release_branch = f'release-R{chrome_major_version}-{chromeos_tip_build}.B-chromeos'
 
-# Find the most recent buildspec for the stable Chrome version and
-# Chromium OS build number.  Its branch build and branch branch build
-# numbers will (almost?) certainly be 0.  It will then end with an rc
-# number -- presumably these are release candidates, one of which
-# becomes the final release.  Presumably the one with the highest rc
-# number.
-with urlopen(f'{buildspecs_url}{chrome_major_version}/?format=TEXT') as resp:
-    listing = base64.decodebytes(resp.read()).decode('utf-8')
-    buildspecs = [(line.split('\t', 1)[1]) for line in listing.splitlines()]
-    buildspecs = [s for s in buildspecs if s.startswith(f"{chromeos_tip_build}.")]
-    buildspecs.sort(reverse=True)
-    buildspec = splitext(buildspecs[0])[0]
-
-# Read the buildspec, and extract the git revision.
-with urlopen(f'{buildspecs_url}{chrome_major_version}/{buildspec}.xml?format=TEXT') as resp:
-    xml = base64.decodebytes(resp.read())
-    root = etree.fromstring(xml)
-    revision = root.find(f'./project[@name="{git_path}"]').get('revision')
-
-# Initialize the data that will be output from this script.  Leave the
-# rc number in buildspec so nobody else is subject to the same level
-# of confusion I have been.
-data = {'version': f'{chrome_major_version}.{buildspec}'}
+# Determine the patch version by counting the commits that have been
+# added to the release branch since it forked off the chromeos branch.
+with urlopen(f'https://chromium.googlesource.com/chromiumos/platform/crosvm/+log/refs/heads/chromeos..refs/heads/{release_branch}?format=JSON') as resp:
+    resp.readline() # Remove )]}' header
+    branch_commits = json.load(resp)['log']
+    data = {'version': f'{chrome_major_version}.{len(branch_commits)}'}
 
 # Fill in the 'src' key with the output from nix-prefetch-git, which
 # can be passed straight to fetchGit when imported by Nix.
 argv = ['nix-prefetch-git',
         '--fetch-submodules',
         '--url', git_root + git_path,
-        '--rev', revision]
+        '--rev', f'refs/heads/{release_branch}']
 output = subprocess.check_output(argv)
 data['src'] = json.loads(output.decode('utf-8'))