[build] Use latest Chrome stable milestone for pinned browsers too

Author: titusfortner

scripts/chrome_version.py

@@ -9,44 +9,19 @@
 
 LAST_KNOWN_GOOD = "https://googlechromelabs.github.io/chrome-for-testing/last-known-good-versions.json"
 KNOWN_GOOD_WITH_DOWNLOADS = "https://googlechromelabs.github.io/chrome-for-testing/known-good-versions-with-downloads.json"
-RELEASES = "https://chromiumdash.appspot.com/fetch_releases"
 
-# Consumer channel rolls out per-platform; these are the platforms we pin binaries for.
-PINNED_PLATFORMS = ("Mac", "Linux")
 
+def latest_for_channel(channel):
+    """Return the newest Chrome-for-Testing version entry (version + downloads) for a channel.
 
-def chrome_for_milestone(milestone):
-    """Return the newest Chrome-for-Testing version entry (version + downloads) for a milestone."""
+    Uses Chrome-for-Testing's channel designation (e.g. "Stable", "Beta"), which tracks the
+    latest milestone and is unaffected by N-1 security respins.
+    """
+    r = http.request("GET", LAST_KNOWN_GOOD)
+    milestone = json.loads(r.data)["channels"][channel]["version"].split(".")[0]
     r = http.request("GET", KNOWN_GOOD_WITH_DOWNLOADS)
     versions = json.loads(r.data)["versions"]
     return sorted(
         filter(lambda v: v["version"].split(".")[0] == str(milestone), versions),
         key=lambda v: parse(v["version"]),
     )[-1]
-
-
-def latest_for_channel(channel):
-    """Newest version Chrome-for-Testing designates for a channel (e.g. "Stable", "Beta").
-
-    Adopts a new milestone as soon as its binaries ship, without waiting for consumer rollout.
-    """
-    r = http.request("GET", LAST_KNOWN_GOOD)
-    milestone = json.loads(r.data)["channels"][channel]["version"].split(".")[0]
-    return chrome_for_milestone(milestone)
-
-
-def conservative_for_channel(channel):
-    """Newest milestone that has reached the consumer channel on every pinned platform.
-
-    Per-platform we take the highest milestone seen (respin-immune: an N-1 security respin
-    can't hide that the platform also has N), then the lowest across platforms so a staggered
-    rollout steps back to N-1 until every platform has N.
-    """
-    milestones = []
-    for platform in PINNED_PLATFORMS:
-        r = http.request("GET", f"{RELEASES}?channel={channel}&num=20&platform={platform}")
-        seen = [release["milestone"] for release in json.loads(r.data) if release["milestone"]]
-        if not seen:
-            raise ValueError(f"No {channel} milestone found for platform '{platform}'")
-        milestones.append(max(seen))
-    return chrome_for_milestone(min(milestones))

scripts/pinned_browsers.py

@@ -7,7 +7,7 @@
 from pathlib import Path
 
 import urllib3
-from chrome_version import conservative_for_channel
+from chrome_version import latest_for_channel
 from packaging.version import parse
 
 # Find the current stable versions of each browser we
@@ -533,12 +533,12 @@ def pin_browsers():
     content = content + edge_and_edgedriver()
 
     # Stable Chrome
-    stable_chrome_info = conservative_for_channel("Stable")
+    stable_chrome_info = latest_for_channel("Stable")
     content = content + chrome(stable_chrome_info, workspace_prefix="")
     content = content + chromedriver(stable_chrome_info, workspace_prefix="")
 
     # Beta Chrome
-    beta_chrome_info = conservative_for_channel("Beta")
+    beta_chrome_info = latest_for_channel("Beta")
     content = content + chrome(beta_chrome_info, workspace_prefix="beta_")
     content = content + chromedriver(beta_chrome_info, workspace_prefix="beta_")