[Mono.Options] Improve error message for badly bundled args.

mono(1) supports a "joined" verbose flag, `mono -v-v-v-v`, which
Mono.Options doesn't support. Attempting to use it, however, resulted
in a "weird" error message:

	$ csharp -r:Mono.Options.dll
	csharp> using Mono.Options;
	csharp> var p = new OptionSet { { "v", v => {} } };
	csharp> p.Parse (new[]{"-v-v-v"});
	Mono.Options.OptionException: Cannot bundle unregistered option '--'.
	...

This looks very weird to users because they never used a "--" option,
and if they had then `--` would have disabled further option
processing (as documented and implemented in OptionSet.Parse()).

Confusion all around.

Improve the error message so that it instead generates:

	Mono.Options.OptionException: Cannot use unregistered option '-' in bundle '-v-v-v'.

That way the user gets the full context of where this "unregistered
option" came from.

2 files changed, 19 insertions, 3 deletions

diff --git a/mcs/class/Mono.Options/Mono.Options/Options.cs b/mcs/class/Mono.Options/Mono.Options/Options.cs
index 5af7fe0f387..0fd21ab5a93 100644
--- a/mcs/class/Mono.Options/Mono.Options/Options.cs
+++ b/mcs/class/Mono.Options/Mono.Options/Options.cs
@@ -1135,7 +1135,7 @@ namespace Mono.Options
 					if (i == 0)
 						return false;
 					throw new OptionException (string.Format (localizer (
-									"Cannot bundle unregistered option '{0}'."), opt), opt);
+									"Cannot use unregistered option '{0}' in bundle '{1}'."), rn, f + n), null);
 				}
 				p = this [rn];
 				switch (p.OptionValueType) {
diff --git a/mcs/class/Mono.Options/Test/Mono.Options/OptionSetTest.cs b/mcs/class/Mono.Options/Test/Mono.Options/OptionSetTest.cs
index 666bad54d5b..086c6d9c8c2 100644
--- a/mcs/class/Mono.Options/Test/Mono.Options/OptionSetTest.cs
+++ b/mcs/class/Mono.Options/Test/Mono.Options/OptionSetTest.cs
@@ -193,7 +193,7 @@ namespace Tests.Mono.Options
 			Assert.AreEqual (libs [1], null);
 
 			Utils.AssertException (typeof(OptionException), 
-					"Cannot bundle unregistered option '-V'.",
+					"Cannot use unregistered option 'V' in bundle '-EVALUENOTSUP'.",
 					p, v => { v.Parse (_("-EVALUENOTSUP")); });
 		}
 
@@ -370,7 +370,7 @@ namespace Tests.Mono.Options
 
 			// try to bundle with an option requiring a value
 			Utils.AssertException (typeof(OptionException), 
-					"Cannot bundle unregistered option '-z'.", 
+					"Cannot use unregistered option 'z' in bundle '-cz'.",
 					p, v => { v.Parse (_("-cz", "extra")); });
 
 			Utils.AssertException (typeof(ArgumentNullException), 
@@ -880,6 +880,22 @@ namespace Tests.Mono.Options
 			Assert.AreEqual (formats ["baz"][0], "e");
 			Assert.AreEqual (formats ["baz"][1], "f");
 		}
+
+		[Test]
+		public void ReportInvalidDuplication ()
+		{
+			int verbosity = 0;
+			var p = new OptionSet () {
+				{ "v", v => verbosity = v != null ? verbosity + 1 : verbosity },
+			};
+			try {
+				p.Parse (new []{"-v-v-v"});
+				Assert.Fail ("Should not be reached.");
+			} catch (OptionException e) {
+				Assert.AreEqual (null, e.OptionName);
+				Assert.AreEqual ("Cannot use unregistered option '-' in bundle '-v-v-v'.", e.Message);
+			}
+		}
 	}
 }