fix(e2e): stop wp-env warm-up JSON parse flakes

[mokagio]

I run into E2E failures from time to time in this repo over the past few weeks. The last time this happened, in the build for PR #533 which I was reviewing, I decided to task an agent to investigate with /goal E2E green consistently. This is the result.

The approach makes sense to me. While one should avoid polling in tests, I think it's acceptable in the context of E2E . But, I'm not familiar withe the Playground / wp-env system that's in use for the tests, so I can't really judge.

I'm sharing this in the hope it helps getting the E2E back to stable, even if just as a starting point.

AI-generated details below.

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What?

Makes the Web E2E job resilient to wp-env warm-up hiccups, which were failing builds intermittently (e.g. build 2401).

Why?

Every failure in the flaky runs traced to wp-env-fixtures.js, where response.json() threw on a non-JSON body returned by the editor-settings/assets REST endpoints during warm-up — either a PHP notice printed into the response (<br /><b>Warning...) or a transient 500. Editor settings are cached in module scope, but only on success, so a single early hiccup poisoned the first fetch and failed every early spec while later ones passed — the classic flaky signature (7 failed / 41 passed with all failures in editor-load, editor-title, editor-error).

How?

Two complementary layers:

• .wp-env.json: set WP_DEBUG_DISPLAY: false so PHP notices never leak into REST bodies. WP_DEBUG_LOG stays on, so they still land in debug.log.
• e2e/wp-env-fixtures.js: route both fetches through a fetchJson helper that reads the body as text, retries transient 5xx/parse failures, and includes a body snippet in the final error instead of an opaque Unexpected token '<'.

Testing Instructions

This is a draft to exercise CI — the goal is a green (and repeatably green) Web E2E job.

Locally: make wp-env-start then make test-e2e. Before this change the settings-fetch failures reproduce on a cold instance; after, the suite passes (verified: 47/49 passed, the 2 remaining being local-only media-upload timeouts under fullyParallel workers, which pass at CI's workers: 1).

[wpmobilebot]

XCFramework Build

This PR's XCFramework is available for testing. Add the following to your Package.swift:

.package(url: "https://github.com/wordpress-mobile/GutenbergKit", branch: "pr-build/540")

_{Built from 4fed003}

[Copilot]

Pull request overview

Improves stability of the Web E2E suite during wp-env warm-up by preventing PHP notices from corrupting REST responses and by making the fixtures/settings fetch more resilient to transient failures.

Changes:

• Adds a fetchJson helper in e2e/wp-env-fixtures.js that retries transient HTTP/parse failures and surfaces a helpful body snippet on final failure.
• Extends bin/wp-env-setup.sh to wait until the editor settings endpoint returns valid JSON before proceeding to run tests.
• Updates .wp-env.json to disable WP_DEBUG_DISPLAY so PHP notices don’t leak into REST response bodies.

Reviewed changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated no comments.

File	Description
e2e/wp-env-fixtures.js	Routes editor settings/assets fetches through a retrying JSON fetch helper to reduce warm-up flakes.
bin/wp-env-setup.sh	Adds a readiness gate for the editor settings REST endpoint to avoid early warm-up failures.
.wp-env.json	Disables debug display to keep REST responses clean while preserving debug logging.

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[iangmaia]

@claude review this PR.

[claude]

Claude finished @iangmaia's task in 0s —— View job

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I'll analyze this and get back to you.

[iangmaia]

Claude finished @iangmaia's task in 0s —— View job

I'll analyze this and get back to you.

FYI #533 isn't merged so ofc this won't trigger the new Claude workflow.