refactor: remove ESBuildContextManager from app-event-watcher

[isaacroldan]

We originally added ESBuildContextManageras a faster way to re-build UI extensions -> by keeping in memory esbuild contexts, re-builds are faster.

This was at the expense of having a custom build pipeline in the app watcher just for ui extensions. This is now causing issues because ui-extensions are not following the standard build flow and therefore not running all "build steps".

This PR removes ESBuildContextManagerand brings back ui-extensions to be compiled like the rest of extensions:

• Simplifies the dev watcher pipeline — one build path instead of two.
• Reduces surface area — ~375 lines of code and tests deleted.
• Makes the watcher easier to reason about — no need to track which extensions use esbuild contexts vs. the default build path.

The benefit of this manager is negligible for small extensions (we might save single digit miliseconds)

[isaacroldan]

• refactor: remove ESBuildContextManager from app-event-watcher #7252 👈 (View in Graphite)
• main

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[Copilot]

Pull request overview

Removes the custom esbuild-context-based build path from the app dev watcher so UI extensions go through the same “standard” build pipeline (and therefore run the same build steps) as other extension types.

Changes:

• Deleted ESBuildContextManager and its dedicated tests.
• Simplified AppEventWatcher to always build extensions via extension.buildForBundle().
• Updated watcher tests to no longer mock/inject the esbuild manager and to simulate errors via the standard build path.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
packages/app/src/cli/services/dev/app-events/app-watcher-esbuild.ts	Removed the custom esbuild context manager implementation.
packages/app/src/cli/services/dev/app-events/app-watcher-esbuild.test.ts	Removed tests tied to the esbuild context manager behavior.
packages/app/src/cli/services/dev/app-events/app-event-watcher.ts	Dropped the esbuild-manager branch and unified extension builds under buildForBundle().
packages/app/src/cli/services/dev/app-events/app-event-watcher.test.ts	Updated tests to match the unified build path; removed esbuild-manager mocking.

Comments suppressed due to low confidence (5)

packages/app/src/cli/services/dev/app-events/app-event-watcher.test.ts:404

• There’s trailing whitespace on this blank line, which will likely fail formatting/linting (Prettier/no-trailing-spaces). Please remove the spaces so it’s an empty line.

          if (needsAppReload) {

packages/app/src/cli/services/dev/app-events/app-event-watcher.test.ts:441

• There’s trailing whitespace on this blank line, which will likely fail formatting/linting (Prettier/no-trailing-spaces). Please remove the spaces so it’s an empty line.

        // Then

packages/app/src/cli/services/dev/app-events/app-event-watcher.test.ts:478

• There’s trailing whitespace on this blank line, which will likely fail formatting/linting (Prettier/no-trailing-spaces). Please remove the spaces so it’s an empty line.

    })

packages/app/src/cli/services/dev/app-events/app-event-watcher.test.ts:512

• There’s trailing whitespace on this blank line, which will likely fail formatting/linting (Prettier/no-trailing-spaces). Please remove the spaces so it’s an empty line.

    })

packages/app/src/cli/services/dev/app-events/app-event-watcher.test.ts:603

• There’s trailing whitespace on this blank line, which will likely fail formatting/linting (Prettier/no-trailing-spaces). Please remove the spaces so it’s an empty line.

          type: 'file_updated',

---

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[vividviolet]

This is working but we lose the stack trace for the errorThe new build process only shows generic errors.

There's also a slight difference in how the extension gets reloaded. I'm pretty sure this is a regression (not related to this PR). When there's a build error the extension isn't supposed to reloaded at all. With this PR we get a reload of the extension with the old code. On main we get a reload with a 500 because the script is missing. This PR improves this behaviour but we're not supposed update the assets at all if the build has failed.

See videos for comparison.

Before

Screen Recording 2026-04-13 at 9.57.33 PM.mov (uploaded via Graphite)

AfterScreen Recording 2026-04-13 at 9.56.20 PM.mov (uploaded via Graphite)

[isaacroldan]

Fixed the missing stacktrace, we should look into the extra updates in a new PR

[isaacroldan]

Merge activity

• Apr 14, 11:12 AM UTC: A user started a stack merge that includes this pull request via Graphite.
• Apr 14, 11:12 AM UTC: @isaacroldan added this pull request to the GitHub merge queue with Graphite.