feat: added overrides to support conflicts in POSIX compatible manner

src/app.rs

@@ -253,7 +253,7 @@ pub struct App<'a, 'v, 'ab, 'u, 'h, 'ar> {
     bin_name: Option<String>,
     usage: Option<String>,
     groups: HashMap<&'ar str, ArgGroup<'ar, 'ar>>,
-    global_args: Vec<Arg<'ar, 'ar, 'ar, 'ar, 'ar, 'ar>>,
+    global_args: Vec<Arg<'ar, 'ar, 'ar, 'ar, 'ar, 'ar, 'ar>>,
     help_str: Option<&'u str>,
     no_sc_error: bool,
     wait_on_error: bool,
@@ -266,7 +266,8 @@ pub struct App<'a, 'v, 'ab, 'u, 'h, 'ar> {
     global_ver: bool,
     // None = not set, Some(true) set for all children, Some(false) = disable version
     versionless_scs: Option<bool>,
-    unified_help: bool
+    unified_help: bool,
+    overrides: HashSet<&'ar str>, 
 }
 
 impl<'a, 'v, 'ab, 'u, 'h, 'ar> App<'a, 'v, 'ab, 'u, 'h, 'ar>{
@@ -317,7 +318,8 @@ impl<'a, 'v, 'ab, 'u, 'h, 'ar> App<'a, 'v, 'ab, 'u, 'h, 'ar>{
             help_on_no_sc: false,
             global_ver: false,
             versionless_scs: None,
-            unified_help: false
+            unified_help: false,
+            overrides: HashSet::new()
         }
     }
 
@@ -784,13 +786,13 @@ impl<'a, 'v, 'ab, 'u, 'h, 'ar> App<'a, 'v, 'ab, 'u, 'h, 'ar>{
     ///     )
     /// # ;
     /// ```
-    pub fn arg(mut self, a: Arg<'ar, 'ar, 'ar, 'ar, 'ar, 'ar>) -> Self {
+    pub fn arg(mut self, a: Arg<'ar, 'ar, 'ar, 'ar, 'ar, 'ar, 'ar>) -> Self {
         self.add_arg(a);
         self
     }
 
     // actually adds the arguments
-    fn add_arg(&mut self, a: Arg<'ar, 'ar, 'ar, 'ar, 'ar, 'ar>) {
+    fn add_arg(&mut self, a: Arg<'ar, 'ar, 'ar, 'ar, 'ar, 'ar, 'ar>) {
         if self.flags.contains_key(a.name) ||
            self.opts.contains_key(a.name) ||
            self.positionals_name.contains_key(a.name) {
@@ -872,7 +874,8 @@ impl<'a, 'v, 'ab, 'u, 'h, 'ar> App<'a, 'v, 'ab, 'u, 'h, 'ar>{
                 help: a.help,
                 global: a.global,
                 empty_vals: a.empty_vals,
-                validator: None
+                validator: None,
+                overrides: None
             };
             if pb.min_vals.is_some() && !pb.multiple {
                 panic!("Argument \"{}\" does not allow multiple values, yet it is expecting {} \
@@ -935,7 +938,8 @@ impl<'a, 'v, 'ab, 'u, 'h, 'ar> App<'a, 'v, 'ab, 'u, 'h, 'ar>{
                 requires: None,
                 required: a.required,
                 empty_vals: a.empty_vals,
-                validator: None
+                validator: None,
+                overrides: None
             };
             if let Some(ref vec) = ob.val_names {
                 ob.num_vals = Some(vec.len() as u8);
@@ -1008,6 +1012,7 @@ impl<'a, 'v, 'ab, 'u, 'h, 'ar> App<'a, 'v, 'ab, 'u, 'h, 'ar>{
                 global: a.global,
                 multiple: a.multiple,
                 requires: None,
+                overrides: None
             };
             // Check if there is anything in the blacklist (mutually excludes list) and add any
             // values
@@ -1048,7 +1053,7 @@ impl<'a, 'v, 'ab, 'u, 'h, 'ar> App<'a, 'v, 'ab, 'u, 'h, 'ar>{
     ///     )
     /// # ;
     /// ```
-    pub fn args(mut self, args: Vec<Arg<'ar, 'ar, 'ar, 'ar, 'ar, 'ar>>)
+    pub fn args(mut self, args: Vec<Arg<'ar, 'ar, 'ar, 'ar, 'ar, 'ar, 'ar>>)
                 -> Self {
         for arg in args.into_iter() {
             self = self.arg(arg);
@@ -2360,6 +2365,7 @@ impl<'a, 'v, 'ab, 'u, 'h, 'ar> App<'a, 'v, 'ab, 'u, 'h, 'ar>{
                 multiple: false,
                 global: false,
                 requires: None,
+                overrides: None
             };
             self.long_list.insert("help");
             self.flags.insert("hclap_help", arg);
@@ -2380,6 +2386,7 @@ impl<'a, 'v, 'ab, 'u, 'h, 'ar> App<'a, 'v, 'ab, 'u, 'h, 'ar>{
                 multiple: false,
                 global: false,
                 requires: None,
+                overrides: None
             };
             self.long_list.insert("version");
             self.flags.insert("vclap_version", arg);
@@ -2443,6 +2450,9 @@ impl<'a, 'v, 'ab, 'u, 'h, 'ar> App<'a, 'v, 'ab, 'u, 'h, 'ar>{
                     true,
                     Some(matches.args.keys().map(|k| *k).collect()));
             }
+            if self.overrides.contains(v.name) {
+                matches.args.remove(v.name);
+            }
 
             if matches.args.contains_key(v.name) {
                 if !v.multiple {
@@ -2512,10 +2522,16 @@ impl<'a, 'v, 'ab, 'u, 'h, 'ar> App<'a, 'v, 'ab, 'u, 'h, 'ar>{
                     }
                 });
             }
-
+            if let Some(ref ov) = v.overrides {
+                for name in ov {
+                    self.overrides.insert(name);
+                    self.required.remove(name);
+                }
+            }
             if let Some(ref bl) = v.blacklist {
                 for name in bl {
                     self.blacklist.insert(name);
+                    self.overrides.remove(name);
                     self.required.remove(name);
                 }
             }
@@ -2555,6 +2571,9 @@ impl<'a, 'v, 'ab, 'u, 'h, 'ar> App<'a, 'v, 'ab, 'u, 'h, 'ar>{
                     true,
                     Some(matches.args.keys().map(|k| *k).collect()));
             }
+            if self.overrides.contains(v.name) {
+                matches.args.remove(v.name);
+            }
 
             // Make sure this isn't one being added multiple times if it doesn't suppor it
             if matches.args.contains_key(v.name) && !v.multiple {
@@ -2583,9 +2602,16 @@ impl<'a, 'v, 'ab, 'u, 'h, 'ar> App<'a, 'v, 'ab, 'u, 'h, 'ar>{
             self.required.remove(v.name);
 
             // Add all of this flags "mutually excludes" list to the master list
+            if let Some(ref ov) = v.overrides {
+                for name in ov {
+                    self.overrides.insert(name);
+                    self.required.remove(name);
+                }
+            }
             if let Some(ref bl) = v.blacklist {
                 for name in bl {
                     self.blacklist.insert(name);
+                    self.overrides.remove(name);
                     self.required.remove(name);
                 }
             }
@@ -2688,6 +2714,9 @@ impl<'a, 'v, 'ab, 'u, 'h, 'ar> App<'a, 'v, 'ab, 'u, 'h, 'ar>{
                     true,
                     Some(matches.args.keys().map(|k| *k).collect()));
             }
+            if self.overrides.contains(v.name) {
+                matches.args.remove(v.name);
+            }
 
             if matches.args.contains_key(v.name) {
                 if !v.multiple {
@@ -2704,9 +2733,16 @@ impl<'a, 'v, 'ab, 'u, 'h, 'ar> App<'a, 'v, 'ab, 'u, 'h, 'ar>{
                     values: Some(BTreeMap::new())
                 });
             }
+            if let Some(ref ov) = v.overrides {
+                for name in ov {
+                    self.overrides.insert(name);
+                    self.required.remove(name);
+                }
+            }
             if let Some(ref bl) = v.blacklist {
                 for name in bl {
                     self.blacklist.insert(name);
+                    self.overrides.remove(name);
                     self.required.remove(name);
                 }
             }
@@ -2754,6 +2790,9 @@ impl<'a, 'v, 'ab, 'u, 'h, 'ar> App<'a, 'v, 'ab, 'u, 'h, 'ar>{
                     true,
                     Some(matches.args.keys().map(|k| *k).collect()));
             }
+            if self.overrides.contains(v.name) {
+                matches.args.remove(v.name);
+            }
 
             // Make sure this isn't one being added multiple times if it doesn't suppor it
             if matches.args.contains_key(v.name) && !v.multiple {
@@ -2782,9 +2821,16 @@ impl<'a, 'v, 'ab, 'u, 'h, 'ar> App<'a, 'v, 'ab, 'u, 'h, 'ar>{
             self.required.remove(v.name);
 
             // Add all of this flags "mutually excludes" list to the master list
+            if let Some(ref ov) = v.overrides {
+                for name in ov {
+                    self.overrides.insert(name);
+                    self.required.remove(name);
+                }
+            }
             if let Some(ref bl) = v.blacklist {
                 for name in bl {
                     self.blacklist.insert(name);
+                    self.overrides.remove(name);
                     self.required.remove(name);
                 }
             }
@@ -2999,3 +3045,8 @@ impl<'a, 'v, 'ab, 'u, 'h, 'ar> App<'a, 'v, 'ab, 'u, 'h, 'ar>{
         }
     }
 }
+
+#[cfg(tests)]
+mod tests {
+    use clap::{App, Arg, SubCommand};
+}

src/args/arg.rs

@@ -32,7 +32,7 @@ use usageparser::{UsageParser, UsageToken};
 /// // Using a usage string (setting a similar argument to the one above)
 /// Arg::from_usage("-i --input=[input] 'Provides an input file to the program'")
 /// # ).get_matches();
-pub struct Arg<'n, 'l, 'h, 'g, 'p, 'r> {
+pub struct Arg<'n, 'l, 'h, 'g, 'p, 'r, 'o> {
     /// The unique name of the argument, required
     #[doc(hidden)]
     pub name: &'n str,
@@ -93,10 +93,13 @@ pub struct Arg<'n, 'l, 'h, 'g, 'p, 'r> {
     #[doc(hidden)]
     pub global: bool,
     #[doc(hidden)]
-    pub validator: Option<Rc<Fn(String) -> Result<(), String>>>
+    pub validator: Option<Rc<Fn(String) -> Result<(), String>>>,
+    /// A list of names for other arguments that *mutually override* this flag
+    #[doc(hidden)] 
+    pub overrides: Option<Vec<&'o str>>
 }
 
-impl<'n, 'l, 'h, 'g, 'p, 'r> Arg<'n, 'l, 'h, 'g, 'p, 'r> {
+impl<'n, 'l, 'h, 'g, 'p, 'r, 'o> Arg<'n, 'l, 'h, 'g, 'p, 'r, 'o> {
     /// Creates a new instace of `Arg` using a unique string name.
     /// The name will be used by the library consumer to get information about
     /// whether or not the argument was used at runtime.
@@ -135,7 +138,8 @@ impl<'n, 'l, 'h, 'g, 'p, 'r> Arg<'n, 'l, 'h, 'g, 'p, 'r> {
             group: None,
             global: false,
             empty_vals: true,
-            validator: None
+            validator: None,
+            overrides: None
         }
     }
 
@@ -191,7 +195,7 @@ impl<'n, 'l, 'h, 'g, 'p, 'r> Arg<'n, 'l, 'h, 'g, 'p, 'r> {
     /// Arg::from_usage("<input> 'the input file to use'")
     /// ])
     /// # .get_matches();
-    pub fn from_usage(u: &'n str) -> Arg<'n, 'n, 'n, 'g, 'p, 'r> {
+    pub fn from_usage(u: &'n str) -> Arg<'n, 'n, 'n, 'g, 'p, 'r, 'o> {
         assert!(u.len() > 0, "Arg::from_usage() requires a non-zero-length usage string but none \
             was provided");
 
@@ -295,6 +299,7 @@ impl<'n, 'l, 'h, 'g, 'p, 'r> Arg<'n, 'l, 'h, 'g, 'p, 'r> {
             global: false,
             empty_vals: true,
             validator: None,
+            overrides: None,
         }
     }
 
@@ -441,6 +446,26 @@ impl<'n, 'l, 'h, 'g, 'p, 'r> Arg<'n, 'l, 'h, 'g, 'p, 'r> {
         self
     }
 
+    /// Sets a mutually overridable argument by name. I.e. this argument and
+    /// the following argument will override each other in POSIX style
+    ///
+    ///
+    /// # Example
+    ///
+    /// ```no_run
+    /// # use clap::{App, Arg};
+    /// # let myprog = App::new("myprog").arg(Arg::with_name("conifg")
+    /// .mutually_overrides_with("debug")
+    /// # ).get_matches();
+    pub fn mutually_overrides_with(mut self, name: &'o str) -> Self {
+        if let Some(ref mut vec) = self.overrides {
+            vec.push(name);
+        } else {
+            self.overrides = Some(vec![name]);
+        }
+        self
+    }
+
     /// Sets an argument by name that is required when this one is presnet I.e. when
     /// using this argument, the following argument *must* be present.
     ///
@@ -796,8 +821,8 @@ impl<'n, 'l, 'h, 'g, 'p, 'r> Arg<'n, 'l, 'h, 'g, 'p, 'r> {
     }
 }
 
-impl<'n, 'l, 'h, 'g, 'p, 'r, 'z> From<&'z Arg<'n, 'l, 'h, 'g, 'p, 'r>> for Arg<'n, 'l, 'h, 'g, 'p, 'r> {
-    fn from(a: &'z Arg<'n, 'l, 'h, 'g, 'p, 'r>) -> Self {
+impl<'n, 'l, 'h, 'g, 'p, 'r, 'z, 'o> From<&'z Arg<'n, 'l, 'h, 'g, 'p, 'r, 'o>> for Arg<'n, 'l, 'h, 'g, 'p, 'r, 'o> {
+    fn from(a: &'z Arg<'n, 'l, 'h, 'g, 'p, 'r, 'o>) -> Self {
         Arg {
             name: a.name,
             short: a.short,
@@ -817,7 +842,8 @@ impl<'n, 'l, 'h, 'g, 'p, 'r, 'z> From<&'z Arg<'n, 'l, 'h, 'g, 'p, 'r>> for Arg<'
             group: a.group,
             global: a.global,
             empty_vals: a.empty_vals,
-            validator: a.validator.clone()
+            validator: a.validator.clone(),
+            overrides: a.overrides.clone()
         }
     }
 }

src/args/argbuilder/flag.rs

@@ -25,6 +25,8 @@ pub struct FlagBuilder<'n> {
     /// of the argument, no preceding `-`
     pub short: Option<char>,
     pub global: bool,
+    /// A list of names for other arguments that *mutually override* this flag
+    pub overrides: Option<Vec<&'n str>>
 }
 
 impl<'n> Display for FlagBuilder<'n> {

src/args/argbuilder/option.rs

@@ -33,7 +33,9 @@ pub struct OptBuilder<'n> {
     pub val_names: Option<Vec<&'n str>>,
     pub empty_vals: bool,
     pub global: bool,
-    pub validator: Option<Rc<Fn(String) -> StdResult<(), String>>>
+    pub validator: Option<Rc<Fn(String) -> StdResult<(), String>>>,
+    /// A list of names for other arguments that *mutually override* this flag
+    pub overrides: Option<Vec<&'n str>>
 }
 
 impl<'n> Display for OptBuilder<'n> {

src/args/argbuilder/positional.rs

@@ -30,7 +30,9 @@ pub struct PosBuilder<'n> {
     pub min_vals: Option<u8>,
     pub empty_vals: bool,
     pub global: bool,
-    pub validator: Option<Rc<Fn(String) -> StdResult<(), String>>>
+    pub validator: Option<Rc<Fn(String) -> StdResult<(), String>>>,
+    /// A list of names for other arguments that *mutually override* this flag
+    pub overrides: Option<HashSet<&'n str>>,
 }
 
 impl<'n> Display for PosBuilder<'n> {