[webdev] Hide --null-safety option (#2206)

Author: parlough

webdev/CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## 3.0.8
 
+- Hide and deprecate now unsupported `--null-safety` option. - [#2206](https://github.com/dart-lang/webdev/pull/2206)
 - Update Dart SDK constraint to `>=3.2.0-36.0.dev <4.0.0`. - [#2207](https://github.com/dart-lang/webdev/pull/2207)
 - Update `dwds` constraint to `21.0.0`.
 

webdev/README.md

@@ -103,16 +103,6 @@ Common:
                                            "--output" value should be passed to
                                            `build_runner`.
                                            (defaults to "NONE")
--n, --null-safety                          If "sound",
-                                           `package:build_web_compilers` will be
-                                           run with sound null safety support.
-                                           If "unsound",
-                                           `package:build_web_compilers` will be
-                                           run without sound null safety
-                                           support. If "auto", the default
-                                           `package:build_web_compilers`
-                                           behavior is used.
-                                           [sound, unsound, auto (default)]
 -r, --[no-]release                         Build with release mode defaults for
                                            builders.
     --[no-]build-web-compilers             If a dependency on
@@ -145,16 +135,6 @@ Usage: webdev build [arguments]
                                            "--output" value should be passed to
                                            `build_runner`.
                                            (defaults to "web:build")
--n, --null-safety                          If "sound",
-                                           `package:build_web_compilers` will be
-                                           run with sound null safety support.
-                                           If "unsound",
-                                           `package:build_web_compilers` will be
-                                           run without sound null safety
-                                           support. If "auto", the default
-                                           `package:build_web_compilers`
-                                           behavior is used.
-                                           [sound, unsound, auto (default)]
 -r, --[no-]release                         Build with release mode defaults for
                                            builders.
                                            (defaults to on)

webdev/lib/src/command/shared.dart

@@ -33,12 +33,13 @@ void addSharedArgs(ArgParser argParser,
         defaultsTo: nullSafetyAuto,
         allowed: [nullSafetySound, nullSafetyUnsound, nullSafetyAuto],
         help:
-            'If "sound", `package:build_web_compilers` will be run with sound '
-            'null safety support. '
+            'DEPRECATED: If "sound", `package:build_web_compilers` will be run '
+            'with sound null safety support. '
             'If "unsound", `package:build_web_compilers` will be run without '
             'sound null safety support. '
             'If "auto", the default `package:build_web_compilers` '
-            'behavior is used.')
+            'behavior is used.',
+        hide: true)
     ..addFlag(releaseFlag,
         abbr: 'r',
         defaultsTo: releaseDefault,