Extension registry foundation

[cyanzhong]

Extension registry foundation

Adds the foundation for installing and updating editor extensions from a registry. Extensions are now tracked in extensions.json, can be installed via a markedit:// deep link, and are kept up to date on a configurable cadence. This is a standalone, self-contained slice — a management UI and migration of pre-registry scripts will come in follow-ups.

What's new

• extensions.json — app-side state for editor extensions (which are installed, in what order, and update preferences). The filesystem remains the source of truth: scripts added or removed under scripts/ are reconciled into the list on launch.
• Install via deep link — markedit://install-extension?id=<registry-id> (reviewed) or ?url=<https-url> (unreviewed, extra warning). Both always confirm, verify/pin the sha256, and offer a relaunch. Never a silent install.
• Registry index — fetched and cached with ETag revalidation; the last good index is kept for offline use.
• Updates — checked on a cadence (onLaunch / daily / weekly) and acted on per registry.updateStrategy (manual / prompt / automatic). Only registry-installed (version-tracked) extensions are eligible.
• Ordered, enabled-only injection — the editor now injects scripts from extensions.json in declared order, skipping disabled ones, instead of scanning the whole scripts/ directory.

Configuration

extensions.json (defaults shown):

{
  "$schema": "https://raw.githubusercontent.com/MarkEdit-app/schemas/main/extensions.json",
  "registry.url": "https://raw.githubusercontent.com/MarkEdit-app/extensions/main/index.json",
  "registry.updateCheck": "weekly",
  "registry.updateStrategy": "prompt",
  "installed": []
}

• registry.url — overridable to a mirror.
• registry.updateCheck — never / onLaunch / daily / weekly.
• registry.updateStrategy — manual (surface later in the manager UI) / prompt / automatic. Defaults to prompt since injected code is arbitrary JavaScript.

Architecture

New ExtensionCore Swift package (pure logic, unit-tested, no AppKit UI):

• ExtensionConfig — local extensions.json state: installed[], prefs, reconcileInstalled, upsertInstalled.
• ExtensionRegistry — remote index: refresh (conditional GET), cachedIndex, cadence (isCheckDue), availableUpdates.
• ExtensionDownloader — download over HTTPS + 200, verify/pin sha256, atomic write to scripts/<id>.js.
• ExtensionEnvironment — injectable filesystem paths and app version (test seam).

App layer (NSAlert flows):

• ExtensionInstaller — the markedit://install-extension deep link.
• ExtensionUpdater — cadence check -> availableUpdates -> updateStrategy, with a failure alert that names each failed extension and its reason.

Integration points: reconcile at launch (Application), ordered/enabled injection (EditorViewController), deep link + update checks (AppDelegate), default file seed (AppCustomization).

Out of scope (follow-ups)

• Management UI for browsing/enabling/disabling extensions.
• Migrating existing pre-registry scripts into version tracking (will live in the manager UI, driven by user selection).

Testing

• ExtensionCoreTests covers availableUpdates, compatibility checks, schema-version support, reconcile/upsert, and Installed adoption/merging.
• Builds clean; a #if DEBUG debug/mock-index.json hook lets you exercise the update flow locally without hitting the network (compiled out of release).

[Copilot]

Pull request overview

This PR lays the groundwork for a registry-backed extension system: extensions are tracked in extensions.json, can be installed via markedit://install-extension, are injected into the editor in an explicit order, and can be updated on a configured cadence/strategy. It introduces a new ExtensionCore package to encapsulate registry/config/downloading logic and wires it into the macOS app lifecycle and deep-link handling.

Changes:

• Add ExtensionCore (config model + registry cache/refresh + downloader + environment seam) with unit tests.
• Add app-layer install/update flows (ExtensionInstaller, ExtensionUpdater) and integrate them into launch + URL scheme handling.
• Switch script injection to use extensions.json order/enabled state instead of scanning the entire scripts/ folder.

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
MarkEditMac/Sources/Main/Application/Application.swift	Reconcile extensions.json against on-disk scripts at startup.
MarkEditMac/Sources/Main/Application/AppDelegate.swift	Trigger extension update checks and handle markedit://install-extension deep links.
MarkEditMac/Sources/Main/AppCustomization.swift	Seed extensions.json and support loading scripts by explicit filenames.
MarkEditMac/Sources/Extension/ExtensionUpdater.swift	New: update-check + prompt/automatic application flow (UI layer).
MarkEditMac/Sources/Extension/ExtensionInstaller.swift	New: deep-link install flow with confirmation UI and relaunch prompts.
MarkEditMac/Sources/Editor/Controllers/EditorViewController.swift	Inject enabled scripts in configured order from extensions.json.
MarkEditMac/Resources/Localizable.xcstrings	Add localized strings for extension install/update alerts.
MarkEditMac/Modules/Tests/ExtensionCoreTests.swift	New: unit tests for core extension config/registry behaviors.
MarkEditMac/Modules/Sources/ExtensionCore/Internal/ExtensionEnvironment.swift	New: injectable filesystem/app-version environment seam for ExtensionCore.
MarkEditMac/Modules/Sources/ExtensionCore/ExtensionRegistry.swift	New: registry index types + refresh/caching + update detection logic.
MarkEditMac/Modules/Sources/ExtensionCore/ExtensionDownloader.swift	New: HTTPS download + sha256 verification/pinning + atomic install into scripts/.
MarkEditMac/Modules/Sources/ExtensionCore/ExtensionConfig.swift	New: extensions.json encoding/decoding + reconcile/upsert + enabled order.
MarkEditMac/Modules/Package.swift	Add ExtensionCore as a new SwiftPM library target and dependency.
MarkEdit.xcodeproj/project.pbxproj	Wire new app source files and link ExtensionCore product.

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[Copilot]

Pull request overview

Copilot reviewed 14 out of 14 changed files in this pull request and generated 6 comments.

[Copilot]

Pull request overview

Copilot reviewed 14 out of 14 changed files in this pull request and generated 4 comments.

[Copilot]

Pull request overview

Copilot reviewed 14 out of 14 changed files in this pull request and generated 2 comments.

[Copilot]

Pull request overview

Copilot reviewed 14 out of 14 changed files in this pull request and generated 2 comments.