Make the php command 2 times faster to start

CHANGELOG.md

@@ -3,6 +3,9 @@
 
 ### Minor changes
 
+* **2026-11-03**
+  * The `php` command is about 20 ms faster on each call: it detects the changes of the `PHP_*` environment variables without starting PHP a first time. The configuration is now also regenerated when a `PHP_*` variable is removed
+
 * **2026-10-23**
   * Security: php2shell is fixed in the arm64 images too, now that the fixed PHP packages are published for arm64. The php2shell test fails again for a vulnerable image on every architecture
   * The tags of the PHP patch versions (e.g. `8.5.12-v5-cli`) are published again: they were no longer published since 2025-12-10. The `X.Y-v5-*` tags are not affected

Dockerfile.slim.apache

@@ -118,8 +118,8 @@ COPY utils/select_composer_version.sh /usr/local/bin/select_composer_version.sh
 COPY utils/utils.php /usr/local/bin/utils.php
 RUN mv /usr/bin/php /usr/bin/real_php
 COPY utils/php_proxy.sh /usr/bin/php
-COPY utils/check_php_env_var_changes.php /usr/local/bin/check_php_env_var_changes.php
-COPY utils/php_env_var_cache.php /opt/php_env_var_cache.php
+COPY utils/php_env_fingerprint.sh /usr/local/bin/php_env_fingerprint.sh
+RUN touch /opt/php_env_fingerprint
 COPY utils/generate_conf.php /usr/local/bin/generate_conf.php
 COPY utils/setup_extensions.php /usr/local/bin/setup_extensions.php
 

Dockerfile.slim.cli

@@ -118,8 +118,8 @@ COPY utils/select_composer_version.sh /usr/local/bin/select_composer_version.sh
 COPY utils/utils.php /usr/local/bin/utils.php
 RUN mv /usr/bin/php /usr/bin/real_php
 COPY utils/php_proxy.sh /usr/bin/php
-COPY utils/check_php_env_var_changes.php /usr/local/bin/check_php_env_var_changes.php
-COPY utils/php_env_var_cache.php /opt/php_env_var_cache.php
+COPY utils/php_env_fingerprint.sh /usr/local/bin/php_env_fingerprint.sh
+RUN touch /opt/php_env_fingerprint
 COPY utils/generate_conf.php /usr/local/bin/generate_conf.php
 COPY utils/setup_extensions.php /usr/local/bin/setup_extensions.php
 

Dockerfile.slim.fpm

@@ -118,8 +118,8 @@ COPY utils/select_composer_version.sh /usr/local/bin/select_composer_version.sh
 COPY utils/utils.php /usr/local/bin/utils.php
 RUN mv /usr/bin/php /usr/bin/real_php
 COPY utils/php_proxy.sh /usr/bin/php
-COPY utils/check_php_env_var_changes.php /usr/local/bin/check_php_env_var_changes.php
-COPY utils/php_env_var_cache.php /opt/php_env_var_cache.php
+COPY utils/php_env_fingerprint.sh /usr/local/bin/php_env_fingerprint.sh
+RUN touch /opt/php_env_fingerprint
 COPY utils/generate_conf.php /usr/local/bin/generate_conf.php
 COPY utils/setup_extensions.php /usr/local/bin/setup_extensions.php
 

tests-suite/php-ini.sh

@@ -38,6 +38,12 @@ test_environmentErrorReporting() {
   [[ "$RESULT" == "error_reporting => 3 => 3" ]]
   assert_equals "error_reporting => 3 => 3" "$RESULT" "Wrong Environment error reporting"
 }
+test_environmentChangedAfterStart() {
+  RESULT="$(docker run ${RUN_OPTIONS} --rm \
+    "${REPO}:${TAG_PREFIX}${PHP_VERSION}-${BRANCH}-slim-${BRANCH_VARIANT}${ARCH_SUFFIX}" \
+    bash -c 'PHP_INI_MEMORY_LIMIT=512M php -r "echo ini_get(\"memory_limit\"), \" \";"; php -r "echo ini_get(\"memory_limit\");"')"
+  assert_equals "512M -1" "$RESULT" "The configuration is not regenerated when a PHP_* variable is added or removed"
+}
 ############################################################
 ## PHP_INI_SESSION__SAVE_PATH
 ## Tests that environment variables with an equal sign are correctly handled

utils/Dockerfile.slim.blueprint

@@ -117,8 +117,8 @@ COPY utils/select_composer_version.sh /usr/local/bin/select_composer_version.sh
 COPY utils/utils.php /usr/local/bin/utils.php
 RUN mv /usr/bin/php /usr/bin/real_php
 COPY utils/php_proxy.sh /usr/bin/php
-COPY utils/check_php_env_var_changes.php /usr/local/bin/check_php_env_var_changes.php
-COPY utils/php_env_var_cache.php /opt/php_env_var_cache.php
+COPY utils/php_env_fingerprint.sh /usr/local/bin/php_env_fingerprint.sh
+RUN touch /opt/php_env_fingerprint
 COPY utils/generate_conf.php /usr/local/bin/generate_conf.php
 COPY utils/setup_extensions.php /usr/local/bin/setup_extensions.php
 

utils/docker-entrypoint-as-root.sh

@@ -149,8 +149,8 @@ fi
 unset DOCKER_FOR_MAC_REMOTE_HOST
 unset REMOTE_HOST_FOUND
 
-sudo chown docker:docker /opt/php_env_var_cache.php
-/usr/bin/real_php -d display_errors=stderr /usr/local/bin/check_php_env_var_changes.php &> /dev/null
+source /usr/local/bin/php_env_fingerprint.sh
+php_env_fingerprint > /opt/php_env_fingerprint
 
 /usr/bin/real_php -d display_errors=stderr /usr/local/bin/generate_conf.php > /etc/php/${PHP_VERSION}/mods-available/generated_conf.ini
 PHP_VERSION="${PHP_VERSION}" /usr/bin/real_php -d display_errors=stderr /usr/local/bin/setup_extensions.php | sudo bash

utils/php_env_fingerprint.sh

@@ -0,0 +1,7 @@
+# Fingerprint of the PHP_* environment variables the PHP configuration is generated from
+php_env_fingerprint() {
+    local name
+    for name in "${!PHP_@}"; do
+        printf '%s=%s\0' "$name" "${!name}"
+    done | md5sum
+}

utils/php_proxy.sh

@@ -1,21 +1,21 @@
 #!/bin/bash
 
-# Users that cannot use sudo run PHP with the current configuration
-if ! sudo -n chown docker:docker /opt/php_env_var_cache.php 2> /dev/null; then
+source /usr/local/bin/php_env_fingerprint.sh
+
+# The configuration is regenerated only when the PHP_* environment variables changed since its last generation
+FINGERPRINT=$(php_env_fingerprint)
+read -r GENERATED_FINGERPRINT < /opt/php_env_fingerprint
+if [[ "$FINGERPRINT" == "$GENERATED_FINGERPRINT" ]]; then
   exec /usr/bin/real_php "$@"
 fi
 
-REGENERATE=$(/usr/bin/real_php -d display_errors=stderr /usr/local/bin/check_php_env_var_changes.php)
-
-if [[ "$REGENERATE" != "0" ]] && [[ "$REGENERATE" != "1" ]]; then
-  >&2 echo "Unexpected PHP proxy output:"
-  >&2 echo $REGENERATE
-  exit 1
+# Users that cannot use sudo run PHP with the current configuration
+if ! sudo -n true 2> /dev/null; then
+  exec /usr/bin/real_php "$@"
 fi
 
-if [[ "$REGENERATE" == "1" ]]; then
-  /usr/bin/real_php -d display_errors=stderr /usr/local/bin/generate_conf.php | sudo tee "/etc/php/${PHP_VERSION}/mods-available/generated_conf.ini" > /dev/null
-  PHP_VERSION="${PHP_VERSION}" /usr/bin/real_php -d display_errors=stderr /usr/local/bin/setup_extensions.php | sudo bash
-fi
+/usr/bin/real_php -d display_errors=stderr /usr/local/bin/generate_conf.php | sudo tee "/etc/php/${PHP_VERSION}/mods-available/generated_conf.ini" > /dev/null
+PHP_VERSION="${PHP_VERSION}" /usr/bin/real_php -d display_errors=stderr /usr/local/bin/setup_extensions.php | sudo bash
+echo "$FINGERPRINT" | sudo tee /opt/php_env_fingerprint > /dev/null
 
 exec /usr/bin/real_php "$@"