397 better error message when calling macros with arity

Error message for macro arity was +2 for the internal params.
Introduce specific class ArityException to correct it.

Signed-off-by: Stuart Halloway <stu@thinkrelevance.com>

5 files changed, 75 insertions, 3 deletions

diff --git a/src/jvm/clojure/lang/AFn.java b/src/jvm/clojure/lang/AFn.java
index a93cd7ed..26d2a56f 100644
--- a/src/jvm/clojure/lang/AFn.java
+++ b/src/jvm/clojure/lang/AFn.java
@@ -436,7 +436,6 @@ static public Object applyToHelper(IFn ifn, ISeq arglist) throws Exception{
 public Object throwArity(int n){
 	String name = getClass().getSimpleName();
 	int suffix = name.lastIndexOf("__");
-	throw new IllegalArgumentException("Wrong number of args (" + n + ") passed to: "
-	                                   + (suffix == -1 ? name : name.substring(0, suffix)).replace('_', '-'));
+	throw new ArityException(n, (suffix == -1 ? name : name.substring(0, suffix)).replace('_', '-'));
 }
 }
diff --git a/src/jvm/clojure/lang/ArityException.java b/src/jvm/clojure/lang/ArityException.java
new file mode 100644
index 00000000..71041ee3
--- /dev/null
+++ b/src/jvm/clojure/lang/ArityException.java
@@ -0,0 +1,32 @@
+/**
+ *   Copyright (c) Rich Hickey. All rights reserved.
+ *   The use and distribution terms for this software are covered by the
+ *   Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
+ *   which can be found in the file epl-v10.html at the root of this distribution.
+ *   By using this software in any fashion, you are agreeing to be bound by
+ * 	 the terms of this license.
+ *   You must not remove this notice, or any other, from this software.
+ **/
+
+package clojure.lang;
+
+/**
+ * @since 1.3
+ */
+public class ArityException extends IllegalArgumentException {
+
+	final public int actual;
+
+	final public String name;
+
+	public ArityException(int actual, String name) {
+		this(actual, name, null);
+	}
+
+	public ArityException(int actual, String name, Throwable cause) {
+		super("Wrong number of args (" + actual + ") passed to: " + name, cause);
+		this.actual = actual;
+		this.name = name;
+	}
+
+}
diff --git a/src/jvm/clojure/lang/Compiler.java b/src/jvm/clojure/lang/Compiler.java
index d38d25e8..34d46783 100644
--- a/src/jvm/clojure/lang/Compiler.java
+++ b/src/jvm/clojure/lang/Compiler.java
@@ -6027,7 +6027,15 @@ public static Object macroexpand1(Object x) throws Exception{
 		Var v = isMacro(op);
 		if(v != null)
 			{
-			return v.applyTo(RT.cons(form,RT.cons(LOCAL_ENV.get(),form.next())));
+				try
+					{
+						return v.applyTo(RT.cons(form,RT.cons(LOCAL_ENV.get(),form.next())));
+					}
+				catch(ArityException e)
+					{
+						// hide the 2 extra params for a macro
+						throw new ArityException(e.actual - 2, e.name, e);
+					}
 			}
 		else
 			{
diff --git a/test/clojure/test_clojure.clj b/test/clojure/test_clojure.clj
index 2f3fc4f8..d66ecf21 100644
--- a/test/clojure/test_clojure.clj
+++ b/test/clojure/test_clojure.clj
@@ -66,6 +66,7 @@
       :keywords
       :data
       :reflect
+      :errors
       ])
 
 (def test-namespaces
diff --git a/test/clojure/test_clojure/errors.clj b/test/clojure/test_clojure/errors.clj
new file mode 100644
index 00000000..3b849870
--- /dev/null
+++ b/test/clojure/test_clojure/errors.clj
@@ -0,0 +1,32 @@
+;   Copyright (c) Rich Hickey. All rights reserved.
+;   The use and distribution terms for this software are covered by the
+;   Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
+;   which can be found in the file epl-v10.html at the root of this distribution.
+;   By using this software in any fashion, you are agreeing to be bound by
+;   the terms of this license.
+;   You must not remove this notice, or any other, from this software.
+
+;; Tests for error handling and messages
+
+(ns clojure.test-clojure.errors
+  (:use clojure.test)
+  (:import clojure.lang.ArityException))
+
+(defn f0 [] 0)
+
+(defn f1 [a] a)
+
+(defmacro m0 [] `(identity 0))
+
+(defmacro m1 [a] `(inc ~a))
+
+(deftest arity-exception
+  ;; IllegalArgumentException is pre-1.3
+  (is (thrown-with-msg? IllegalArgumentException #"Wrong number of args \(1\) passed to"
+        (f0 1)))
+  (is (thrown-with-msg? ArityException #"Wrong number of args \(0\) passed to"
+        (f1)))
+  (is (thrown-with-msg? ArityException #"Wrong number of args \(1\) passed to"
+        (macroexpand `(m0 1))))
+  (is (thrown-with-msg? ArityException #"Wrong number of args \(2\) passed to"
+        (macroexpand `(m1 1 2)))))