Cleanly disabled [web-root]/.ht.router.php scaffolding + added to CI.

.do/build/composer.sh

@@ -1,16 +1,5 @@
 #!/bin/bash
 
-# We need to remove this since it's not used in production but it is needed for
-# running PHPUnit functional tests in CI. Trying to conditionally remove it via
-# 'composer config --unset extra.drupal-scaffold.file-mapping."[web-root]/.htaccess"'
-# or multiple such variations with various characters in the last key escaped
-# seem to have no effect, despite the fact that fetching the config by leaving
-# out '--unset' works correctly.
-#
-# @todo Figure out why running the above command doesn't remove the key, add it
-#   back to the scaffold, and remove this command.
-rm /workspace/web/.ht.router.php
-
 # Dump optimized Composer autoloader using APCu for production.
 #
 # @see https://getcomposer.org/doc/articles/autoloader-optimization.md

.github/workflows/main.yml

@@ -90,6 +90,27 @@ jobs:
           key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}
           restore-keys: ${{ runner.os }}-composer-
 
+      # This file is set in our composer.json to not be scaffolded by default
+      # since it's not needed in production and local dev environments. However,
+      # it's not possible to run:
+      #
+      # composer config --unset \
+      #   extra.drupal-scaffold.file-mapping."[web-root]/.ht.router.php"
+      #
+      # because Composer will ignore more than 3 nesting levels passed to the
+      # config command by design. Thankfully, it's possible to get the full
+      # JSON contents of the file-mapping key, which we can then modify with jq
+      # and set regardless of nesting level.
+      #
+      # @see https://getcomposer.org/doc/03-cli.md#modifying-extra-values
+      #   Documentation states a max nesting level of 3.
+      #
+      # @see https://jqlang.github.io/jq/manual/
+      - name: Scaffold .ht.router.php for PHPUnit tests
+        run: composer config extra.drupal-scaffold.file-mapping --json \
+          $(composer config extra.drupal-scaffold.file-mapping | \
+          jq --compact-output 'del(."[web-root]/.ht.router.php")')
+
       - name: Install Composer dependencies
         run: composer install --no-progress --prefer-dist --optimize-autoloader
 

composer.json

@@ -294,6 +294,7 @@
         "[project-root]/.gitattributes": {
           "append": "drupal_scaffold/gitattributes_append.txt"
         },
+        "[web-root]/.ht.router.php": false,
         "[web-root]/.htaccess": {
           "prepend": "drupal_scaffold/htaccess_prepend.txt",
           "append": "drupal_scaffold/htaccess_append.txt"