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# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
"""Generate channel-prefs.js by substituting @MOZ_UPDATE_CHANNEL@.
The input has no preprocessor directives, so every line is written
verbatim and the preprocessor never emits a `//@line N "<path>"`
marker. The substitution filter then replaces `@MOZ_UPDATE_CHANNEL@`
in place.
Byte stability of the installed file matters because the macOS updater
leaves `channel-prefs.js` alone after first install. Code signature
verification fails when an update arrives with different bytes than
The comment at the top of `profile/channel-prefs.js` still points at
`browser/app/Makefile.in`. That pointer is intentionally stale because
updating the template's content would change its shipped bytes.
Adding a preprocessor directive to `profile/channel-prefs.js` would
reintroduce `//@line` markers, which `main` asserts against."""
import io
import buildconfig
from mozbuild.preprocessor import Preprocessor
def main(output, input_path):
pp = Preprocessor()
pp.do_filter("substitution")
pp.context["MOZ_UPDATE_CHANNEL"] = buildconfig.substs["MOZ_UPDATE_CHANNEL"]
result = io.StringIO()
with open(input_path, encoding="utf-8") as fh:
pp.processFile(fh, result)
contents = result.getvalue()
assert "//@line" not in contents, (
f"{input_path} produced `//@line` markers; channel-prefs.js must be "
)
output.write(contents)