## Problem/Motivation Following the DDEV workflow documented in `CONTRIBUTING.md`: ``` ddev exec phpunit drupal_cms_installer/tests/src/Functional/InteractiveInstallTest.php ``` the test fails: ``` 1) Drupal\Tests\drupal_cms_installer\Functional\InteractiveInstallTest::testPostInstallState Behat\Mink\Exception\ExpectationException: Current page is "/core/install.php", but "/admin/dashboard/welcome" expected. /var/www/html/drupal_cms_installer/tests/src/Functional/InteractiveInstallTest.php:113 ``` The test's own browser output shows the install batch reaching ~80% ("Installed Stark theme. 80% Completed 44 of 55") and the next batch request returning `502 Bad Gateway`. `ddev logs -s web` explains why: ``` [error] upstream sent too big header while reading response header from upstream, request: "GET /core/install.php?profile=drupal_cms_installer&langcode=en&name=Installer%20Test&template=1&id=1&op=do_nojs", upstream: "fastcgi://unix:/run/php/php-fpm.sock:" ``` Root cause: inside a child test site, core emits one `X-Drupal-Assertion-N` response header per PHP notice/deprecation, with no cap on the number or total size (`core/includes/errors.inc:375`). Applying the Drupal CMS site templates triggers a large number of contrib deprecations (`easy_email_requirements` and `automatic_updates_requirements` without `#[LegacyRequirementsHook]`, the deprecated `cache.static` service, and others). Measured from the browser output dumps of one run, the assertion headers peak at roughly 53 KB across 68 headers in a single batch response. DDEV's generated `.ddev/nginx_full/nginx-site.conf` configures: ``` fastcgi_buffers 16 16k; fastcgi_buffer_size 32k; ``` `fastcgi_buffer_size` must hold the entire response header, so any response above 32 KB of headers becomes a 502. CI does not catch this: the `phpunit` job inherits the default image `drupalci/php-8.4-ubuntu-apache:production`, i.e. Apache, while `.ddev/config.dev.yaml` sets `webserver_type: nginx-fpm`. The test is green on CI and broken for anyone running it the way CONTRIBUTING.md prescribes. ## Steps to reproduce 1. `ddev start` on 2.x with the default configuration. 2. `ddev exec phpunit drupal_cms_installer/tests/src/Functional/InteractiveInstallTest.php` 3. The test fails as above, and `ddev logs -s web` contains "upstream sent too big header". Environment where this was observed: DDEV v1.25.3, nginx-fpm, PHP 8.4, macOS (mutagen). ## Proposed resolution Raise the FastCGI response-header buffers in the DDEV web container. The customization path DDEV documents for this file (edit `.ddev/nginx_full/nginx-site.conf` and remove its `#ddev-generated` marker) is not usable here: - `.ddev/.gitignore` ignores `/nginx_full/nginx-site.conf`, so the file cannot ship in the repository; and - on DDEV v1.25.3 the file is regenerated on start even with the marker removed. This was tested twice — once with `ddev restart`, once by editing while the project was stopped — and in both cases DDEV restored the marker and the 32k default. That looks like a DDEV bug and deserves its own upstream issue, since `.ddev/nginx_full/README.nginx_full.txt` explicitly promises the takeover works. So the practical fix is a `post-start` hook in the tracked `.ddev/config.dev.yaml`, which already defines hooks: ```yaml hooks: post-start: # Functional tests return one X-Drupal-Assertion-* response header per # deprecation notice. Installing Drupal CMS blows past nginx's 32k default # FastCGI header buffer, so nginx answers 502 ("upstream sent too big # header") mid-install. DDEV regenerates .ddev/nginx_full/nginx-site.conf on # every start, so patch the live config instead. - exec: sudo sed -i 's/fastcgi_buffers 16 16k;/fastcgi_buffers 64 64k;/; s/fastcgi_buffer_size 32k;/fastcgi_buffer_size 1m;/' /etc/nginx/sites-enabled/nginx-site.conf && sudo nginx -s reload ``` Note: leave `fastcgi_busy_buffers_size` at its default. nginx refuses to start if it is not smaller than the total buffer pool minus one buffer, so an explicit `1m` alongside `fastcgi_buffers 32 32k` fails `nginx -t`. Verified locally with this hook in place: `InteractiveInstallTest` passes (`OK (1 test, 23 assertions)`), and it keeps passing after `ddev restart`, i.e. the hook re-applies the buffers on a cold start. ## Remaining tasks - Agree on the approach: the `post-start` hook above, or aligning the DDEV webserver with CI (`apache-fpm`) so local and CI environments match. - File the DDEV issue about `nginx_full/nginx-site.conf` being regenerated despite the `#ddev-generated` marker having been removed. - Optional, separate: report/fix the contrib deprecations that inflate the headers. That shrinks the payload but does not remove the cliff, since the header count grows with every new deprecation. ## User interface changes None. ## API changes None. ## Data model changes None. ## LLM disclosure LLM was used to come up with this issue and document it. I use the suggested fix locally and it works.