Add COMPOSER_NO_DEV environment variable to set the --no-dev flag (#10262)

doc/03-cli.md

@@ -1163,3 +1163,8 @@ If set to `1`, outputs information about events being dispatched, which can be
 useful for plugin authors to identify what is firing when exactly.
 
 ← [Libraries](02-libraries.md)  |  [Schema](04-schema.md) →
+
+### COMPOSER_NO_DEV
+
+If set to `1`, it is the equivalent of passing the `--no-dev` arguement to `install` or
+`update`. You can override this for a single command by setting `COMPOSER_NO_DEV=0`.

src/Composer/Command/BaseCommand.php

@@ -153,6 +153,12 @@ abstract class BaseCommand extends Command
             $input->setOption('no-progress', true);
         }
 
+        if (true == $input->hasOption('no-dev')) {
+            if (!$input->getOption('no-dev') && true == Platform::getEnv('COMPOSER_NO_DEV')) {
+                $input->setOption('no-dev', true);
+            }
+        }
+
         parent::initialize($input, $output);
     }