Add COMPOSER_PREFER_STABLE and COMPOSER_PREFER_LOWEST env vars, fixes #10919

doc/03-cli.md

@@ -218,9 +218,11 @@ and this feature is only available for your root package dependencies.
   a `+` makes it only ignore the upper-bound of the requirements. For example, if a package
   requires `php: ^7`, then the option `--ignore-platform-req=php+` would allow installing on PHP 8,
   but installation on PHP 5.6 would still fail.
-* **--prefer-stable:** Prefer stable versions of dependencies.
+* **--prefer-stable:** Prefer stable versions of dependencies. Can also be set via the
+  COMPOSER_PREFER_STABLE=1 env var.
 * **--prefer-lowest:** Prefer lowest versions of dependencies. Useful for testing minimal
-  versions of requirements, generally used with `--prefer-stable`.
+  versions of requirements, generally used with `--prefer-stable`. Can also be set via the
+  COMPOSER_PREFER_LOWEST=1 env var.
 * **--interactive:** Interactive interface with autocompletion to select the packages to update.
 * **--root-reqs:** Restricts the update to your first degree dependencies.
 
@@ -275,9 +277,11 @@ If you do not specify a package, Composer will prompt you to search for a packag
 * **--ignore-platform-req:** ignore a specific platform requirement(`php`,
   `hhvm`, `lib-*` and `ext-*`) and force the installation even if the local machine
   does not fulfill it. Multiple requirements can be ignored via wildcard.
-* **--prefer-stable:** Prefer stable versions of dependencies.
+* **--prefer-stable:** Prefer stable versions of dependencies. Can also be set via the
+  COMPOSER_PREFER_STABLE=1 env var.
 * **--prefer-lowest:** Prefer lowest versions of dependencies. Useful for testing minimal
-  versions of requirements, generally used with `--prefer-stable`.
+  versions of requirements, generally used with `--prefer-stable`. Can also be set via the
+  COMPOSER_PREFER_LOWEST=1 env var.
 * **--sort-packages:** Keep packages sorted in `composer.json`.
 * **--optimize-autoloader (-o):** Convert PSR-0/4 autoloading to classmap to
   get a faster autoloader. This is recommended especially for production, but
@@ -1233,9 +1237,19 @@ useful for plugin authors to identify what is firing when exactly.
 
 ### COMPOSER_NO_DEV
 
-If set to `1`, it is the equivalent of passing the `--no-dev` argument to `install` or
+If set to `1`, it is the equivalent of passing the `--no-dev` option to `install` or
 `update`. You can override this for a single command by setting `COMPOSER_NO_DEV=0`.
 
+### COMPOSER_PREFER_STABLE
+
+If set to `1`, it is the equivalent of passing the `--prefer-stable` option to
+`update` or `require`.
+
+### COMPOSER_PREFER_LOWEST
+
+If set to `1`, it is the equivalent of passing the `--prefer-lowest` option to
+`update` or `require`.
+
 ### COMPOSER_IGNORE_PLATFORM_REQ or COMPOSER_IGNORE_PLATFORM_REQS
 
 If `COMPOSER_IGNORE_PLATFORM_REQS` set to `1`, it is the equivalent of passing the `--ignore-platform-reqs` argument.

src/Composer/Command/BaseCommand.php

@@ -243,9 +243,16 @@ abstract class BaseCommand extends Command
             $input->setOption('no-progress', true);
         }
 
-        if (true === $input->hasOption('no-dev')) {
+        $envOptions = [
-            if (!$input->getOption('no-dev') && (bool) Platform::getEnv('COMPOSER_NO_DEV')) {
+            'COMPOSER_NO_DEV' => 'no-dev',
-                $input->setOption('no-dev', true);
+            'COMPOSER_PREFER_STABLE' => 'prefer-stable',
+            'COMPOSER_PREFER_LOWEST' => 'prefer-lowest',
+        ];
+        foreach ($envOptions as $envName => $optionName) {
+            if (true === $input->hasOption($optionName)) {
+                if (false === $input->getOption($optionName) && (bool) Platform::getEnv($envName)) {
+                    $input->setOption($optionName, true);
+                }
             }
         }
 

src/Composer/Command/RequireCommand.php

@@ -90,8 +90,8 @@ class RequireCommand extends BaseCommand
                 new InputOption('with-all-dependencies', null, InputOption::VALUE_NONE, 'Alias for --update-with-all-dependencies'),
                 new InputOption('ignore-platform-req', null, InputOption::VALUE_REQUIRED | InputOption::VALUE_IS_ARRAY, 'Ignore a specific platform requirement (php & ext- packages).'),
                 new InputOption('ignore-platform-reqs', null, InputOption::VALUE_NONE, 'Ignore all platform requirements (php & ext- packages).'),
-                new InputOption('prefer-stable', null, InputOption::VALUE_NONE, 'Prefer stable versions of dependencies.'),
+                new InputOption('prefer-stable', null, InputOption::VALUE_NONE, 'Prefer stable versions of dependencies (can also be set via the COMPOSER_PREFER_STABLE=1 env var).'),
-                new InputOption('prefer-lowest', null, InputOption::VALUE_NONE, 'Prefer lowest versions of dependencies.'),
+                new InputOption('prefer-lowest', null, InputOption::VALUE_NONE, 'Prefer lowest versions of dependencies (can also be set via the COMPOSER_PREFER_LOWEST=1 env var).'),
                 new InputOption('sort-packages', null, InputOption::VALUE_NONE, 'Sorts packages when adding/updating a new dependency'),
                 new InputOption('optimize-autoloader', 'o', InputOption::VALUE_NONE, 'Optimize autoloader during autoloader dump'),
                 new InputOption('classmap-authoritative', 'a', InputOption::VALUE_NONE, 'Autoload classes from the classmap only. Implicitly enables `--optimize-autoloader`.'),

src/Composer/Command/UpdateCommand.php

@@ -75,8 +75,8 @@ class UpdateCommand extends BaseCommand
                 new InputOption('apcu-autoloader-prefix', null, InputOption::VALUE_REQUIRED, 'Use a custom prefix for the APCu autoloader cache. Implicitly enables --apcu-autoloader'),
                 new InputOption('ignore-platform-req', null, InputOption::VALUE_REQUIRED | InputOption::VALUE_IS_ARRAY, 'Ignore a specific platform requirement (php & ext- packages).'),
                 new InputOption('ignore-platform-reqs', null, InputOption::VALUE_NONE, 'Ignore all platform requirements (php & ext- packages).'),
-                new InputOption('prefer-stable', null, InputOption::VALUE_NONE, 'Prefer stable versions of dependencies.'),
+                new InputOption('prefer-stable', null, InputOption::VALUE_NONE, 'Prefer stable versions of dependencies (can also be set via the COMPOSER_PREFER_STABLE=1 env var).'),
-                new InputOption('prefer-lowest', null, InputOption::VALUE_NONE, 'Prefer lowest versions of dependencies.'),
+                new InputOption('prefer-lowest', null, InputOption::VALUE_NONE, 'Prefer lowest versions of dependencies (can also be set via the COMPOSER_PREFER_LOWEST=1 env var).'),
                 new InputOption('interactive', 'i', InputOption::VALUE_NONE, 'Interactive interface with autocompletion to select the packages to update.'),
                 new InputOption('root-reqs', null, InputOption::VALUE_NONE, 'Restricts the update to your first degree dependencies.'),
             ))