fix!: Make ArgAction::Set the default

CHANGELOG.md

@@ -20,6 +20,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - `arg!` now sets `ArgAction::SetTrue`, `ArgAction::Count`, `ArgAction::Set`, or `ArgAction::Append` as appropriate (#3795)
 - Default actions are now `Set` and `SetTrue`
 - Removed `PartialEq` and `Eq` from `Command`
+- By default, an `Arg`s default action is `ArgAction::Set`, rather than `ArgAction::SetTrue`
 - Replace `Arg::number_of_values` (average across occurrences) with `Arg::num_args` (per occurrence, raw CLI args, not parsed values)
   - `num_args(0)` no longer implies `takes_value(true).multiple_values(true)`
   - `num_args(1)` no longer implies `multiple_values(true)`

clap_bench/benches/03_complex.rs

@@ -67,12 +67,13 @@ pub fn build_from_builder(c: &mut Criterion) {
                         .help("tests flags")
                         .long("flag")
                         .global(true)
-                        .action(ArgAction::Append),
+                        .action(ArgAction::Count),
                 )
                 .arg(
                     Arg::new("flag2")
                         .short('F')
                         .help("tests flags with exclusions")
+                        .action(ArgAction::SetTrue)
                         .conflicts_with("flag")
                         .requires("option2"),
                 )

clap_bench/benches/04_new_help.rs

@@ -42,7 +42,8 @@ fn app_example3<'c>() -> Command<'c> {
         .arg(
             Arg::new("debug")
                 .help("turn on debugging information")
-                .short('d'),
+                .short('d')
+                .action(ArgAction::SetTrue),
         )
         .args(&[
             Arg::new("config")
@@ -73,6 +74,7 @@ fn app_example4<'c>() -> Command<'c> {
             Arg::new("debug")
                 .help("turn on debugging information")
                 .short('d')
+                .action(ArgAction::SetTrue)
                 .long("debug"),
         )
         .arg(

clap_bench/benches/05_ripgrep.rs

@@ -299,7 +299,7 @@ where
     F: Fn(&'static str) -> &'static str,
 {
     let arg = |name| Arg::new(name).help(doc(name));
-    let flag = |name| arg(name).long(name);
+    let flag = |name| arg(name).long(name).action(ArgAction::SetTrue);
 
     Command::new("ripgrep")
         .author("BurntSushi") // simulating since it's only a bench
@@ -379,18 +379,21 @@ where
         .arg(
             flag("after-context")
                 .short('A')
+                .action(ArgAction::Set)
                 .value_name("NUM")
                 .value_parser(value_parser!(usize)),
         )
         .arg(
             flag("before-context")
                 .short('B')
+                .action(ArgAction::Set)
                 .value_name("NUM")
                 .value_parser(value_parser!(usize)),
         )
         .arg(
             flag("context")
                 .short('C')
+                .action(ArgAction::Set)
                 .value_name("NUM")
                 .value_parser(value_parser!(usize)),
         )
@@ -419,11 +422,13 @@ where
         .arg(
             flag("max-count")
                 .short('m')
+                .action(ArgAction::Set)
                 .value_name("NUM")
                 .value_parser(value_parser!(usize)),
         )
         .arg(
             flag("maxdepth")
+                .action(ArgAction::Set)
                 .value_name("NUM")
                 .value_parser(value_parser!(usize)),
         )
@@ -436,13 +441,19 @@ where
         .arg(flag("null"))
         .arg(flag("path-separator").value_name("SEPARATOR"))
         .arg(flag("pretty").short('p'))
-        .arg(flag("replace").short('r').value_name("ARG"))
+        .arg(
+            flag("replace")
+                .short('r')
+                .action(ArgAction::Set)
+                .value_name("ARG"),
+        )
         .arg(flag("case-sensitive").short('s'))
         .arg(flag("smart-case").short('S'))
         .arg(flag("sort-files"))
         .arg(
             flag("threads")
                 .short('j')
+                .action(ArgAction::Set)
                 .value_name("ARG")
                 .value_parser(value_parser!(usize)),
         )

clap_bench/benches/06_rustup.rs

@@ -30,7 +30,8 @@ fn build_cli() -> Command<'static> {
             Arg::new("verbose")
                 .help("Enable verbose output")
                 .short('v')
-                .long("verbose"),
+                .long("verbose")
+                .action(ArgAction::SetTrue),
         )
         .subcommand(
             Command::new("show")
@@ -53,6 +54,7 @@ fn build_cli() -> Command<'static> {
                     Arg::new("no-self-update")
                         .help("Don't perform self update when running the `rustup` command")
                         .long("no-self-update")
+                        .action(ArgAction::SetTrue)
                         .hide(true),
                 ),
         )
@@ -210,6 +212,7 @@ fn build_cli() -> Command<'static> {
                         .arg(
                             Arg::new("nonexistent")
                                 .long("nonexistent")
+                                .action(ArgAction::SetTrue)
                                 .help("Remove override toolchain for all nonexistent directories"),
                         ),
                 )
@@ -226,6 +229,7 @@ fn build_cli() -> Command<'static> {
                         .arg(
                             Arg::new("nonexistent")
                                 .long("nonexistent")
+                                .action(ArgAction::SetTrue)
                                 .help("Remove override toolchain for all nonexistent directories"),
                         ),
                 ),
@@ -250,11 +254,13 @@ fn build_cli() -> Command<'static> {
                 .arg(
                     Arg::new("book")
                         .long("book")
+                        .action(ArgAction::SetTrue)
                         .help("The Rust Programming Language book"),
                 )
                 .arg(
                     Arg::new("std")
                         .long("std")
+                        .action(ArgAction::SetTrue)
                         .help("Standard library API documentation"),
                 )
                 .group(ArgGroup::new("page").args(&["book", "std"])),
@@ -276,7 +282,7 @@ fn build_cli() -> Command<'static> {
                 .subcommand(
                     Command::new("uninstall")
                         .about("Uninstall rustup.")
-                        .arg(Arg::new("no-prompt").short('y')),
+                        .arg(Arg::new("no-prompt").short('y').action(ArgAction::SetTrue)),
                 )
                 .subcommand(
                     Command::new("upgrade-data").about("Upgrade the internal data format."),

clap_complete/src/shells/zsh.rs

@@ -623,13 +623,14 @@ fn write_positionals_of(p: &Command) -> String {
         debug!("write_positionals_of:iter: arg={}", arg.get_id());
 
         let num_args = arg.get_num_args().expect("built");
-        let cardinality = if num_args != 1.into() && num_args != 0.into() {
-            "*:"
-        } else if !arg.is_required_set() {
-            ":"
-        } else {
-            ""
-        };
+        let cardinality =
+            if num_args != builder::ValueRange::EMPTY && num_args != builder::ValueRange::SINGLE {
+                "*:"
+            } else if !arg.is_required_set() {
+                ":"
+            } else {
+                ""
+            };
 
         let a = format!(
             "'{cardinality}:{name}{help}:{value_completion}' \\",

clap_complete_fig/src/fig.rs

@@ -335,7 +335,7 @@ fn gen_args(arg: &Arg, indent: usize) -> String {
     ));
 
     let num_args = arg.get_num_args().expect("built");
-    if num_args != 0.into() && num_args != 1.into() {
+    if num_args != builder::ValueRange::EMPTY && num_args != builder::ValueRange::SINGLE {
         buffer.push_str(&format!(
             "{:indent$}isVariadic: true,\n",
             "",