0037. Policies read without blocking on every start

Status

Accepted. Replaces the synchronous read of a start without a cache in ADR 0025.

Date

2026-11-09

Context

ADR 0025 reads policies while Electron starts and applies the cached state until then, but reads the sources synchronously on a start without a cache, so that Chromium switches from policies apply on the very first start. To read synchronously, the start-up path of the browser process had to contain the parsers of registry exports and property lists on every system, although each system needs one of them at most: they were about 7 KB of the 150 KB that the start-up path may have (ADR 0017). No policy sets a Chromium switch yet; those that are planned, such as for proxies and sign-in, can be applied while the browser runs.

Decision

• One way to read: the policy providers only read without blocking. Every start applies the cached state, if there is one, and the bootstrap awaits the fresh read after ready, before the settings and the first window.
• Parsers per system: the provider of the Windows registry loads the parser of registry exports with its first read, and the provider of macOS loads the parser of property lists once a profile exists. Linux needs neither.
• Chromium switches: a policy that can only take effect as a Chromium switch before ready applies from the start after the one that first read it, with the notice that a restart is required, as ADR 0025 already sets for a policy that changes.

Everything else in ADR 0025 and ADR 0012 stays in force.

Consequences

Positive:

• Smaller start: the start-up path of the browser process loses about 7 KB, and on Linux the parsers never load.
• One path: the start without a cache and the start with one read the same way.

Negative:

• First start: a policy that needs a Chromium switch does not apply on the very first start of a profile.

Alternatives considered

• Keeping the synchronous read: it needs the parsers of every system in the start-up path.
• Loading the parsers synchronously from separate files: the bundle of the browser process is an ES module, which cannot load a module synchronously.