fix: Ease transition for now-default settings

We prefer Settings to always be off by default, so when we change a
default, we have to rename.

This adds back in the now-default settings with deprecation messages to
help the user know how things now work.

Unfortunately, there is no way to notify the user that the default they
relied on has changed.  This also doesn't help us when the change in
behavior is more than just an inverting, like `InvalidUtf8` or when a
setting mapped to multiple bits.

src/build/app/settings.rs

@@ -50,6 +50,7 @@ bitflags! {
         const IGNORE_ERRORS                  = 1 << 44;
         #[cfg(feature = "unstable-multicall")]
         const MULTICALL                      = 1 << 45;
+        const NO_OP                          = 0;
     }
 }
 
@@ -72,6 +73,8 @@ impl_settings! { AppSettings, AppFlags,
         => Flags::ARGS_NEGATE_SCS,
     AllowExternalSubcommands("allowexternalsubcommands")
         => Flags::ALLOW_UNK_SC,
+    StrictUtf8("strictutf8")
+        => Flags::NO_OP,
     AllowInvalidUtf8ForExternalSubcommands("allowinvalidutf8forexternalsubcommands")
         => Flags::SC_UTF8_NONE,
     AllowLeadingHyphen("allowleadinghyphen")
@@ -80,6 +83,8 @@ impl_settings! { AppSettings, AppFlags,
         => Flags::ALLOW_NEG_NUMS,
     AllowMissingPositional("allowmissingpositional")
         => Flags::ALLOW_MISSING_POS,
+    ColoredHelp("coloredhelp")
+        => Flags::NO_OP,
     ColorAlways("coloralways")
         => Flags::COLOR_ALWAYS,
     ColorAuto("colorauto")
@@ -131,6 +136,7 @@ impl_settings! { AppSettings, AppFlags,
         => Flags::USE_LONG_FORMAT_FOR_HELP_SC,
     TrailingVarArg("trailingvararg")
         => Flags::TRAILING_VARARG,
+    UnifiedHelp("unifiedhelp") => Flags::NO_OP,
     NextLineHelp("nextlinehelp")
         => Flags::NEXT_LINE_HELP,
     IgnoreErrors("ignoreerrors")
@@ -157,6 +163,13 @@ impl_settings! { AppSettings, AppFlags,
 /// [`App`]: crate::App
 #[derive(Debug, PartialEq, Copy, Clone)]
 pub enum AppSettings {
+    /// Deprecated, this is now the default, see [`AppSettings::AllowInvalidUtf8ForExternalSubcommands`] and [`ArgSettings::AllowInvalidUtf8ForExternalSubcommands`] for the opposite.
+    #[deprecated(
+        since = "3.0.0",
+        note = "This is now the default see [`AppSettings::AllowInvalidUtf8ForExternalSubcommands`] and [`ArgSettings::AllowInvalidUtf8ForExternalSubcommands`] for the opposite."
+    )]
+    StrictUtf8,
+
     /// Specifies that external subcommands that are invalid UTF-8 should *not* be treated as an error.
     ///
     /// **NOTE:** Using external subcommand argument values with invalid UTF-8 requires using
@@ -498,6 +511,10 @@ pub enum AppSettings {
     /// ```
     SubcommandPrecedenceOverArg,
 
+    /// Deprecated, this is now the default
+    #[deprecated(since = "3.0.0", note = "This is now the default")]
+    ColoredHelp,
+
     /// Deprecated, see [`App::color`]
     #[deprecated(since = "3.0.0", note = "Replaced with `App::color`")]
     ColorAuto,
@@ -1023,6 +1040,10 @@ pub enum AppSettings {
     /// [`Arg::multiple_values(true)`]: crate::Arg::multiple_values()
     TrailingVarArg,
 
+    /// Deprecated, this is now the default
+    #[deprecated(since = "3.0.0", note = "This is now the default")]
+    UnifiedHelp,
+
     /// Will display a message "Press \[ENTER\]/\[RETURN\] to continue..." and wait for user before
     /// exiting
     ///

src/build/arg/settings.rs

@@ -31,6 +31,7 @@ bitflags! {
         #[cfg(feature = "env")]
         const HIDE_ENV         = 1 << 21;
         const UTF8_NONE        = 1 << 22;
+        const NO_OP            = 0;
     }
 }
 
@@ -51,6 +52,7 @@ impl_settings! { ArgSettings, ArgFlags,
     MultipleValues("multiplevalues") => Flags::MULTIPLE_VALS,
     Multiple("multiple") => Flags::MULTIPLE,
     ForbidEmptyValues("forbidemptyvalues") => Flags::NO_EMPTY_VALS,
+    EmptyValues("emptyvalues") => Flags::NO_OP,
     Hidden("hidden") => Flags::HIDDEN,
     TakesValue("takesvalue") => Flags::TAKES_VAL,
     UseValueDelimiter("usevaluedelimiter") => Flags::USE_DELIM,
@@ -97,6 +99,13 @@ pub enum ArgSettings {
     Multiple,
     /// Forbids an arg from accepting empty values such as `""`
     ForbidEmptyValues,
+    /// Deprecated, this is now the default, see [`ArgSettings::ForbidEmptyValues`] for the
+    /// opposite.
+    #[deprecated(
+        since = "3.0.0",
+        note = "This is now the default see [`ArgSettings::ForbidEmptyValues`] for the opposite."
+    )]
+    EmptyValues,
     /// Hides an arg from the help message
     Hidden,
     /// Allows an argument to take a value (such as `--option value`)