feat(ci/android): play-upload can attach release notes and promote a build

Two things it could not do, both needed now that a tag ships to production.

Release notes: it never sent `releaseNotes`, so Play's "What's new" was whatever
the previous release said. It now takes --release-notes-file, and refuses text
over Play's 500-char-per-language cap with the actual count — that check has to
happen before the upload, because the API only rejects it at commit, by which
point the AAB is already on Play.

Promotion: --promote assigns a versionCode that is already on Play instead of
uploading, so what reaches production is the byte-identical artifact the testers
ran. Rebuilding would mint a fresh versionCode from possibly-newer sources and
ship something nobody tested. --promote-from asserts the code really is on that
track (a typo'd versionCode now fails before it touches production) and clears
that track in the SAME edit, so the build is never active on both at once.

--user-fraction comes along because --status inProgress is an API error without
it; it is validated as strictly between 0 and 1 rather than left to Google.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

clients/android/ci/play-upload.py

@@ -6,13 +6,23 @@ Why hand-rolled: stdlib + `openssl` only (no pip on the runner), and it prints G
 error at the stage it fails instead of a catch-all. Reuses the SERVICE_ACCOUNT_JSON secret and
 tolerates it being raw JSON *or* base64-encoded JSON.
 
-Usage:
+Usage (upload a new build):
   SERVICE_ACCOUNT_JSON='<raw-or-base64 SA key>' \
     python3 play-upload.py --package io.unom.punktfunk \
       --aab path/to/app-release.aab --track internal --status completed [--no-commit]
 
---no-commit: do insert -> upload -> track-update -> validate, then delete the edit (publishes
-nothing). Use it to dry-run the credentials/AAB without touching the live track.
+Usage (promote a build that is already on Play, no rebuild):
+  python3 play-upload.py --package io.unom.punktfunk \
+      --promote 10816 --promote-from alpha --track production
+
+Promotion assigns an EXISTING versionCode to another track, so what ships to production is the
+byte-identical artifact the testers ran — rebuilding would burn a fresh versionCode and ship
+something nobody has tested. --promote-from additionally asserts the code really is on that track
+(catches a typo'd versionCode before it reaches production) and empties it in the SAME edit, so
+the move is atomic: testers are never left pinned to a code that production also serves.
+
+--no-commit: do insert -> upload/assign -> track-update -> validate, then delete the edit
+(publishes nothing). Use it to dry-run the credentials/AAB/notes without touching the live track.
 """
 import argparse, base64, json, os, subprocess, sys, tempfile, time
 import urllib.request, urllib.parse, urllib.error
@@ -104,18 +114,79 @@ def access_token(sa) -> str:
     return tok["access_token"]
 
 
+# Play's "What's new" is capped at 500 characters per language. The cap lives in the Console
+# (the REST reference does not state it) and the API rejects longer text at commit — i.e. AFTER
+# the AAB has uploaded — so check it up front and print the actual count.
+NOTES_MAX = 500
+
+
+def load_release_notes(path, language):
+    with open(path, encoding="utf-8") as f:
+        text = f.read().strip()
+    if not text:
+        sys.exit(f"ERROR: release-notes file is empty: {path}")
+    if len(text) > NOTES_MAX:
+        sys.exit(f"ERROR: release notes are {len(text)} chars, Play allows {NOTES_MAX}: {path}")
+    print(f"release notes: {len(text)}/{NOTES_MAX} chars ({language})")
+    return [{"language": language, "text": text}]
+
+
+def put_track(app, edit, tok, track, version_codes, status, user_fraction=None, notes=None):
+    """PUT one track. An empty version_codes list clears the track (what promotion does to the
+    track it promoted OUT of)."""
+    release = {"status": status, "versionCodes": [str(v) for v in version_codes]}
+    if user_fraction is not None:
+        release["userFraction"] = user_fraction
+    if notes:
+        release["releaseNotes"] = notes
+    # Clearing a track means "no active releases", not "an empty release".
+    body = {"track": track, "releases": [release] if version_codes else []}
+    call("PUT", f"{app}/edits/{edit}/tracks/{track}", token=tok,
+         data=json.dumps(body).encode(), content_type="application/json")
+
+
+def assert_on_track(app, edit, tok, track, vc):
+    """Fail before anything is written if --promote names a versionCode that is not actually on
+    the track we claim to be promoting out of."""
+    got = call("GET", f"{app}/edits/{edit}/tracks/{track}", token=tok)
+    live = [c for r in got.get("releases", []) for c in r.get("versionCodes", [])]
+    if str(vc) not in live:
+        sys.exit(f"ERROR: versionCode {vc} is not on track '{track}' (it has: {live or 'nothing'})")
+    print(f"verified versionCode={vc} is live on '{track}'")
+
+
 def main():
     ap = argparse.ArgumentParser()
     ap.add_argument("--package", required=True)
-    ap.add_argument("--aab", required=True)
+    ap.add_argument("--aab", help="upload this bundle (mutually exclusive with --promote)")
+    ap.add_argument("--promote", type=int, metavar="VERSIONCODE",
+                    help="assign an already-uploaded versionCode instead of uploading")
+    ap.add_argument("--promote-from", metavar="TRACK",
+                    help="with --promote: assert the code is on TRACK, then clear TRACK")
     ap.add_argument("--track", default="internal")
     ap.add_argument("--status", default="completed")
+    ap.add_argument("--user-fraction", type=float,
+                    help="staged rollout fraction, 0<f<1; required by --status inProgress")
+    ap.add_argument("--release-notes-file", help="Play 'What's new' text (<=500 chars)")
+    ap.add_argument("--release-notes-language", default="en-US")
     ap.add_argument("--no-commit", action="store_true")
     a = ap.parse_args()
 
-    if not os.path.isfile(a.aab):
+    if bool(a.aab) == bool(a.promote):
+        sys.exit("ERROR: pass exactly one of --aab (upload) or --promote (assign an existing code)")
+    if a.promote_from and not a.promote:
+        sys.exit("ERROR: --promote-from only applies to --promote")
+    # inProgress without a fraction is an API error; halted/completed with one is also rejected.
+    if a.status == "inProgress" and a.user_fraction is None:
+        sys.exit("ERROR: --status inProgress requires --user-fraction")
+    if a.user_fraction is not None and not (0 < a.user_fraction < 1):
+        sys.exit(f"ERROR: --user-fraction must be strictly between 0 and 1 (got {a.user_fraction})")
+    if a.aab and not os.path.isfile(a.aab):
         sys.exit(f"ERROR: AAB not found: {a.aab}")
 
+    notes = load_release_notes(a.release_notes_file, a.release_notes_language) \
+        if a.release_notes_file else None
+
     sa = load_sa()
     tok = access_token(sa)
     print(f"authenticated as {sa['client_email']} (project {sa.get('project_id')})")
@@ -123,17 +194,25 @@ def main():
 
     try:
         edit = call("POST", f"{app}/edits", token=tok)["id"]
-        with open(a.aab, "rb") as f:
-            blob = f.read()
-        print(f"uploading {a.aab} ({len(blob)} bytes) ...")
-        vc = call("POST", f"{UPLOAD}/{a.package}/edits/{edit}/bundles?uploadType=media",
-                  token=tok, data=blob, content_type="application/octet-stream")["versionCode"]
-        print(f"uploaded versionCode={vc}")
-        call("PUT", f"{app}/edits/{edit}/tracks/{a.track}", token=tok,
-             data=json.dumps({"track": a.track,
-                              "releases": [{"status": a.status, "versionCodes": [str(vc)]}]}).encode(),
-             content_type="application/json")
-        print(f"assigned versionCode={vc} -> track={a.track} status={a.status}")
+        if a.promote:
+            vc = a.promote
+            if a.promote_from:
+                assert_on_track(app, edit, tok, a.promote_from, vc)
+        else:
+            with open(a.aab, "rb") as f:
+                blob = f.read()
+            print(f"uploading {a.aab} ({len(blob)} bytes) ...")
+            vc = call("POST", f"{UPLOAD}/{a.package}/edits/{edit}/bundles?uploadType=media",
+                      token=tok, data=blob, content_type="application/octet-stream")["versionCode"]
+            print(f"uploaded versionCode={vc}")
+
+        put_track(app, edit, tok, a.track, [vc], a.status, a.user_fraction, notes)
+        print(f"assigned versionCode={vc} -> track={a.track} status={a.status}"
+              + (f" userFraction={a.user_fraction}" if a.user_fraction is not None else ""))
+        # Same edit as the assignment above, so the code is never active on both tracks at once.
+        if a.promote_from:
+            put_track(app, edit, tok, a.promote_from, [], a.status)
+            print(f"cleared track '{a.promote_from}'")
 
         if a.no_commit:
             call("POST", f"{app}/edits/{edit}:validate", token=tok)