gitlab-ci: only run fdroid build on changed build entries

.gitlab-ci.yml

@@ -150,7 +150,6 @@ fdroid build:
 
     - bash fdroidserver/buildserver/provision-apt-get-install http://deb.debian.org/debian
     - apt-get dist-upgrade
-    - apt-get install sudo # TODO REMOVE ME once merged https://gitlab.com/fdroid/fdroidserver/-/merge_requests/753
 
     # install fdroidserver from git, with deps from Debian, until fdroidserver
     # is stable enough to include all the things needed here
@@ -162,7 +161,12 @@ fdroid build:
     - apt-get purge fdroidserver
 
     - export GRADLE_USER_HOME=$PWD/.gradle
-    - fdroid build --verbose --on-server --latest --no-tarball --no-refresh  $CHANGED
+    # each `fdroid build --on-server` run expects sudo, then uninstalls it
+    - for build in `./tools/find-changed-builds.py`; do
+          set -x;
+          apt-get install sudo;
+          fdroid build --verbose --on-server --no-tarball $build;
+      done
 
 
 # issuebot needs secrets to run, so it has to run under the 'fdroid'

tools/find-changed-builds.py

@@ -0,0 +1,50 @@
+#!/usr/bin/env python3
+
+import difflib
+import os
+import subprocess
+import sys
+import yaml
+from colorama import Fore, Style
+
+changed = set(os.getenv('CHANGED').split(' '))
+changed.discard('')
+
+for appid in sorted(changed):
+    metadata_file = 'metadata/%s.yml' % appid
+    diff = subprocess.check_output(
+        ('git diff --no-color --diff-filter=d FETCH_HEAD...HEAD -- ' + metadata_file).split(' '),
+    )
+
+    with open(metadata_file) as fp:
+        current = yaml.safe_load(fp)
+    cmd = 'git apply --reverse'
+    p = subprocess.run(cmd.split(' '), input=diff, stdout=subprocess.DEVNULL)
+    if p.returncode:
+        print(Fore.RED + ('ERROR: %s: %d' % (cmd, p.returncode)) + Style.RESET_ALL,
+              file=sys.stderr)
+        sys.exit(p.returncode)
+    with open(metadata_file) as fp:
+        previous = yaml.safe_load(fp)
+    cmd = 'git apply'
+    p = subprocess.run(cmd.split(' '), input=diff, stdout=subprocess.DEVNULL)
+    if p.returncode:
+        print(Fore.RED + ('ERROR: %s: %d' % (cmd, p.returncode)) + Style.RESET_ALL,
+              file=sys.stderr)
+        sys.exit(p.returncode)
+
+    to_build = []
+    previous_builds = dict()
+    for build in previous['Builds']:
+        previous_builds[build['versionCode']] = build
+
+    for build in current['Builds']:
+        vc = build['versionCode']
+        if vc not in previous_builds:
+            to_build.append(vc)
+            continue
+        if build != previous_builds[vc]:
+            to_build.append(vc)
+
+    for vc in to_build:
+        print('%s:%d' % (appid, vc), end=' ')