fix(assert): Allow stateful value parsers

We'll need to re-evaluate how to solve clap-rs#3202.

Fixes clap-rs#4643

clap_builder/src/builder/debug_asserts.rs

@@ -1,8 +1,5 @@
 use std::cmp::Ordering;
 
-use clap_lex::OsStrExt as _;
-
-use crate::builder::OsStr;
 use crate::builder::ValueRange;
 use crate::mkeymap::KeyType;
 use crate::util::FlatSet;
@@ -809,20 +806,6 @@ fn assert_arg(arg: &Arg) {
     }
 
     assert_arg_flags(arg);
-
-    assert_defaults(arg, "default_value", arg.default_vals.iter());
-    assert_defaults(
-        arg,
-        "default_missing_value",
-        arg.default_missing_vals.iter(),
-    );
-    assert_defaults(
-        arg,
-        "default_value_if",
-        arg.default_vals_ifs
-            .iter()
-            .filter_map(|(_, _, default)| default.as_ref()),
-    );
 }
 
 fn assert_arg_flags(arg: &Arg) {
@@ -854,37 +837,3 @@ fn assert_arg_flags(arg: &Arg) {
     checker!(is_multiple_values_set requires is_takes_value_set);
     checker!(is_ignore_case_set requires is_takes_value_set);
 }
-
-fn assert_defaults<'d>(
-    arg: &Arg,
-    field: &'static str,
-    defaults: impl IntoIterator<Item = &'d OsStr>,
-) {
-    for default_os in defaults {
-        let value_parser = arg.get_value_parser();
-        let assert_cmd = Command::new("assert");
-        if let Some(val_delim) = arg.get_value_delimiter() {
-            let mut val_delim_buffer = [0; 4];
-            let val_delim = val_delim.encode_utf8(&mut val_delim_buffer);
-            for part in default_os.split(val_delim) {
-                if let Err(err) = value_parser.parse_ref(&assert_cmd, Some(arg), part) {
-                    panic!(
-                        "Argument `{}`'s {}={:?} failed validation: {}",
-                        arg.get_id(),
-                        field,
-                        part.to_string_lossy(),
-                        err
-                    );
-                }
-            }
-        } else if let Err(err) = value_parser.parse_ref(&assert_cmd, Some(arg), default_os) {
-            panic!(
-                "Argument `{}`'s {}={:?} failed validation: {}",
-                arg.get_id(),
-                field,
-                default_os,
-                err
-            );
-        }
-    }
-}

tests/builder/default_missing_vals.rs

@@ -258,38 +258,6 @@ fn delimited_missing_value() {
     );
 }
 
-#[cfg(debug_assertions)]
-#[test]
-#[cfg(feature = "error-context")]
-#[should_panic = "Argument `arg`'s default_missing_value=\"value\" failed validation: error: invalid value 'value' for '[arg]'"]
-fn default_missing_values_are_possible_values() {
-    use clap::{Arg, Command};
-
-    let _ = Command::new("test")
-        .arg(
-            Arg::new("arg")
-                .value_parser(["one", "two"])
-                .default_missing_value("value"),
-        )
-        .try_get_matches();
-}
-
-#[cfg(debug_assertions)]
-#[test]
-#[cfg(feature = "error-context")]
-#[should_panic = "Argument `arg`'s default_missing_value=\"value\" failed validation: error: invalid value 'value' for '[arg]"]
-fn default_missing_values_are_valid() {
-    use clap::{Arg, Command};
-
-    let _ = Command::new("test")
-        .arg(
-            Arg::new("arg")
-                .value_parser(clap::value_parser!(u32))
-                .default_missing_value("value"),
-        )
-        .try_get_matches();
-}
-
 #[test]
 fn valid_index() {
     let m = Command::new("df")

tests/builder/default_vals.rs

@@ -793,38 +793,6 @@ fn required_args_with_default_values() {
     assert!(m.contains_id("arg"));
 }
 
-#[cfg(debug_assertions)]
-#[test]
-#[cfg(feature = "error-context")]
-#[should_panic = "Argument `arg`'s default_value=\"value\" failed validation: error: invalid value 'value' for '[arg]'"]
-fn default_values_are_possible_values() {
-    use clap::{Arg, Command};
-
-    let _ = Command::new("test")
-        .arg(
-            Arg::new("arg")
-                .value_parser(["one", "two"])
-                .default_value("value"),
-        )
-        .try_get_matches();
-}
-
-#[cfg(debug_assertions)]
-#[test]
-#[cfg(feature = "error-context")]
-#[should_panic = "Argument `arg`'s default_value=\"one\" failed validation: error: invalid value 'one' for '[arg]"]
-fn invalid_default_values() {
-    use clap::{Arg, Command};
-
-    let _ = Command::new("test")
-        .arg(
-            Arg::new("arg")
-                .value_parser(clap::value_parser!(u32))
-                .default_value("one"),
-        )
-        .try_get_matches();
-}
-
 #[test]
 fn valid_delimited_default_values() {
     use clap::{Arg, Command};
@@ -839,23 +807,6 @@ fn valid_delimited_default_values() {
         .debug_assert();
 }
 
-#[cfg(debug_assertions)]
-#[test]
-#[cfg(feature = "error-context")]
-#[should_panic = "Argument `arg`'s default_value=\"one\" failed validation: error: invalid value 'one' for '[arg]"]
-fn invalid_delimited_default_values() {
-    use clap::{Arg, Command};
-
-    Command::new("test")
-        .arg(
-            Arg::new("arg")
-                .value_parser(clap::value_parser!(u32))
-                .value_delimiter(',')
-                .default_value("one,two"),
-        )
-        .debug_assert();
-}
-
 #[test]
 fn with_value_delimiter() {
     let cmd = Command::new("multiple_values").arg(