fix(parser)!: Split on value delimiter after validating num_args

This will allow `num_args(0..=1).value_delimiter(',')` to work properly.

This hacks in support for `require_value_delimiter` until we can remove
it.

This no longer recognzes value terminators in delimited lists.

It looks like there is a bug with recognizing value terminators in
positionals arguments.  We'll need to dig into that more.

Author: epage

CHANGELOG.md

@@ -23,7 +23,9 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - 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)`
-  - Does not check default values, only what the user explicitly passes in
+  - Does not check default or env values, only what the user explicitly passes in
+  - No longer terminates on delimited values
+- `Arg::value_terminator` must stand on its own now rather than being in a delimited list
 - Sometimes `Arg::default_missing_value` didn't require `num_args(0..=1)`, now it does
 - Replace `Arg::min_values` (across all occurrences) with `Arg::num_args(N..)` (per occurrence)
 - Replace `Arg::max_values` (across all occurrences) with `Arg::num_args(1..=M)` (per occurrence)

src/error/kind.rs

@@ -104,9 +104,8 @@ pub enum ErrorKind {
     /// # use clap::{Command, Arg, error::ErrorKind};
     /// let result = Command::new("prog")
     ///     .arg(Arg::new("arg")
-    ///         .num_args(1..=2)
-    ///         .require_value_delimiter(true))
-    ///     .try_get_matches_from(vec!["prog", "too,many,values"]);
+    ///         .num_args(1..=2))
+    ///     .try_get_matches_from(vec!["prog", "too", "many", "values"]);
     /// assert!(result.is_err());
     /// assert_eq!(result.unwrap_err().kind(), ErrorKind::TooManyValues);
     /// ```

src/parser/arg_matcher.rs

@@ -202,7 +202,9 @@ impl ArgMatcher {
             "ArgMatcher::needs_more_vals: o={}, pending={}",
             o.name, num_pending
         );
-        if let Some(expected) = o.get_num_args() {
+        if num_pending == 1 && o.is_require_value_delimiter_set() {
+            false
+        } else if let Some(expected) = o.get_num_args() {
             debug!(
                 "ArgMatcher::needs_more_vals: expected={}, actual={}",
                 expected, num_pending
@@ -221,19 +223,35 @@ impl ArgMatcher {
         &mut self,
         id: &Id,
         ident: Option<Identifier>,
+        trailing_values: bool,
     ) -> &mut Vec<OsString> {
         let pending = self.pending.get_or_insert_with(|| PendingArg {
             id: id.clone(),
             ident,
             raw_vals: Default::default(),
+            trailing_idx: None,
         });
         debug_assert_eq!(pending.id, *id, "{}", INTERNAL_ERROR_MSG);
         if ident.is_some() {
             debug_assert_eq!(pending.ident, ident, "{}", INTERNAL_ERROR_MSG);
         }
+        if trailing_values {
+            pending
+                .trailing_idx
+                .get_or_insert_with(|| pending.raw_vals.len());
+        }
         &mut pending.raw_vals
     }
 
+    pub(crate) fn start_trailing(&mut self) {
+        if let Some(pending) = &mut self.pending {
+            // Allow asserting its started on subsequent calls
+            pending
+                .trailing_idx
+                .get_or_insert_with(|| pending.raw_vals.len());
+        }
+    }
+
     pub(crate) fn take_pending(&mut self) -> Option<PendingArg> {
         self.pending.take()
     }