Add tests, fix grouped_values_of()

Fix clippy

src/parse/matches/arg_matches.rs

@@ -242,8 +242,21 @@ impl ArgMatches {
     }
 
     /// Placeholder documentation.
-    pub fn grouped_values_of<T: Key>(&self, id: T) -> Option<Iter<Vec<OsString>>> {
-        self.args.get(&Id::from(id)).map(|arg| arg.vals())
+    pub fn grouped_values_of<T: Key>(&self, id: T) -> Option<GroupedValues> {
+        #[allow(clippy::type_complexity)]
+        let arg_values: for<'a> fn(
+            &'a MatchedArg,
+        ) -> Map<
+            std::slice::Iter<'a, Vec<OsString>>,
+            fn(&Vec<OsString>) -> Vec<&str>,
+        > = |arg| {
+            arg.vals()
+                .map(|g| g.iter().map(|x| x.to_str().expect(INVALID_UTF8)).collect())
+        };
+        self.args
+            .get(&Id::from(id))
+            .map(arg_values)
+            .map(|iter| GroupedValues { iter })
     }
 
     /// Gets the lossy values of a specific argument. If the option wasn't present at runtime
@@ -1017,12 +1030,44 @@ impl<'a> ExactSizeIterator for Values<'a> {}
 impl<'a> Default for Values<'a> {
     fn default() -> Self {
         static EMPTY: [Vec<OsString>; 0] = [];
-        // This is never called because the iterator is empty:
-        fn to_str_slice(_: &OsString) -> &str {
-            unreachable!()
-        }
         Values {
-            iter: EMPTY[..].iter().flatten().map(to_str_slice),
+            iter: EMPTY[..].iter().flatten().map(|_| unreachable!()),
+        }
+    }
+}
+
+#[derive(Clone)]
+#[allow(missing_debug_implementations)]
+pub struct GroupedValues<'a> {
+    #[allow(clippy::type_complexity)]
+    iter: Map<std::slice::Iter<'a, Vec<OsString>>, fn(&Vec<OsString>) -> Vec<&str>>,
+}
+
+impl<'a> Iterator for GroupedValues<'a> {
+    type Item = Vec<&'a str>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.iter.next()
+    }
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.iter.size_hint()
+    }
+}
+
+impl<'a> DoubleEndedIterator for GroupedValues<'a> {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        self.iter.next_back()
+    }
+}
+
+impl<'a> ExactSizeIterator for GroupedValues<'a> {}
+
+/// Creates an empty iterator. Used for `unwrap_or_default()`.
+impl<'a> Default for GroupedValues<'a> {
+    fn default() -> Self {
+        static EMPTY: [Vec<OsString>; 0] = [];
+        GroupedValues {
+            iter: EMPTY[..].iter().map(|_| unreachable!()),
         }
     }
 }
@@ -1078,12 +1123,8 @@ impl<'a> ExactSizeIterator for OsValues<'a> {}
 impl Default for OsValues<'_> {
     fn default() -> Self {
         static EMPTY: [Vec<OsString>; 0] = [];
-        // This is never called because the iterator is empty:
-        fn to_str_slice(_: &OsString) -> &OsStr {
-            unreachable!()
-        }
         OsValues {
-            iter: EMPTY[..].iter().flatten().map(to_str_slice),
+            iter: EMPTY[..].iter().flatten().map(|_| unreachable!()),
         }
     }
 }

src/parse/parser.rs

@@ -1251,7 +1251,7 @@ impl<'help, 'app> Parser<'help, 'app> {
                     }
                     vals
                 } else {
-                    arg_split.into_iter().collect()
+                    arg_split.collect()
                 };
                 let vals = vals.into_iter().map(|x| x.to_os_string()).collect();
                 self.add_multiple_vals_to_arg(arg, vals, matcher, ty, append);

tests/grouped_values.rs

@@ -0,0 +1,94 @@
+mod utils;
+
+use clap::{App, Arg};
+
+#[test]
+fn value_sets_works() {
+    let m = App::new("cli")
+        .arg(Arg::new("option").long("option").multiple(true))
+        .get_matches_from(&[
+            "cli",
+            "--option",
+            "fr_FR:mon option 1",
+            "en_US:my option 1",
+            "--option",
+            "fr_FR:mon option 2",
+            "en_US:my option 2",
+        ]);
+    let grouped_vals: Vec<_> = m.grouped_values_of("option").unwrap().collect();
+    assert_eq!(
+        grouped_vals,
+        vec![
+            vec!["fr_FR:mon option 1", "en_US:my option 1",],
+            vec!["fr_FR:mon option 2", "en_US:my option 2",],
+        ]
+    );
+}
+
+#[test]
+fn issue_1026() {
+    let m = App::new("cli")
+        .arg(Arg::new("server").short('s').takes_value(true))
+        .arg(Arg::new("user").short('u').takes_value(true))
+        .arg(Arg::new("target").long("target").multiple(true))
+        .get_matches_from(&[
+            "backup", "-s", "server", "-u", "user", "--target", "target1", "file1", "file2",
+            "file3", "--target", "target2", "file4", "file5", "file6", "file7", "--target",
+            "target3", "file8",
+        ]);
+    let grouped_vals: Vec<_> = m.grouped_values_of("target").unwrap().collect();
+    assert_eq!(
+        grouped_vals,
+        vec![
+            vec!["target1", "file1", "file2", "file3"],
+            vec!["target2", "file4", "file5", "file6", "file7",],
+            vec!["target3", "file8"]
+        ]
+    );
+}
+
+#[test]
+fn value_sets_long_flag_delimiter() {
+    let m = App::new("myapp")
+        .arg(
+            Arg::new("option")
+                .long("option")
+                .takes_value(true)
+                .use_delimiter(true)
+                .multiple(true),
+        )
+        .get_matches_from(vec![
+            "myapp",
+            "--option=hmm",
+            "--option=val1,val2,val3",
+            "--option",
+            "alice,bob",
+        ]);
+    let grouped_vals: Vec<_> = m.grouped_values_of("option").unwrap().collect();
+    assert_eq!(
+        grouped_vals,
+        vec![
+            vec!["hmm"],
+            vec!["val1", "val2", "val3"],
+            vec!["alice", "bob"]
+        ]
+    );
+}
+
+#[test]
+fn value_sets_short_flag_delimiter() {
+    let m = App::new("myapp")
+        .arg(
+            Arg::new("option")
+                .short('o')
+                .takes_value(true)
+                .use_delimiter(true)
+                .multiple(true),
+        )
+        .get_matches_from(vec!["myapp", "-o=foo", "-o=val1,val2,val3", "-o=bar"]);
+    let grouped_vals: Vec<_> = m.grouped_values_of("option").unwrap().collect();
+    assert_eq!(
+        grouped_vals,
+        vec![vec!["foo"], vec!["val1", "val2", "val3"], vec!["bar"]]
+    );
+}