restore detection of cyclic load dependencies

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

10 files changed, 124 insertions, 8 deletions

diff --git a/src/clj/clojure/core.clj b/src/clj/clojure/core.clj
index 6fa139dd..16186d47 100644
--- a/src/clj/clojure/core.clj
+++ b/src/clj/clojure/core.clj
@@ -5071,8 +5071,8 @@
 
 (defonce ^:dynamic
   ^{:private true
-     :doc "the set of paths currently being loaded by this thread"}
-  *pending-paths* #{})
+     :doc "A stack of paths currently being loaded by this thread"}
+  *pending-paths* ())
 
 (defonce ^:dynamic
   ^{:private true :doc
@@ -5206,8 +5206,20 @@
           (doseq [arg args]
             (apply load-lib prefix (prependss arg opts))))))))
 
-;; Public
+(defn- check-cyclic-dependency
+  "Detects and rejects non-trivial cyclic load dependencies. The
+  exception message shows the dependency chain with the cycle
+  highlighted. Ignores the trivial case of a file attempting to load
+  itself because that can occur when a gen-class'd class loads its
+  implementation."
+  [path]
+  (when (some #{path} (rest *pending-paths*))
+    (let [pending (map #(if (= % path) (str "[ " % " ]") %)
+                       (cons path *pending-paths*))
+          chain (apply str (interpose "->" pending))]
+      (throw (Exception. (str "Cyclic load dependency: " chain))))))
 
+;; Public
 
 (defn require
   "Loads libs, skipping any that are already loaded. Each argument is
@@ -5300,12 +5312,10 @@
       (when *loading-verbosely*
         (printf "(clojure.core/load \"%s\")\n" path)
         (flush))
-;      (throw-if (*pending-paths* path)
-;                "cannot load '%s' again while it is loading"
-;                path)
-      (when-not (*pending-paths* path)
+      (check-cyclic-dependency path)
+      (when-not (= path (first *pending-paths*))
         (binding [*pending-paths* (conj *pending-paths* path)]
-          (clojure.lang.RT/load  (.substring path 1)))))))
+          (clojure.lang.RT/load (.substring path 1)))))))
 
 (defn compile
   "Compiles the namespace named by the symbol lib into a set of
diff --git a/src/script/run_tests.clj b/src/script/run_tests.clj
index 5b4ba07e..ef29cd43 100644
--- a/src/script/run_tests.clj
+++ b/src/script/run_tests.clj
@@ -23,6 +23,7 @@ clojure.test-clojure.java.javadoc
 clojure.test-clojure.java.shell
 clojure.test-clojure.java-interop
 clojure.test-clojure.keywords
+clojure.test-clojure.load
 clojure.test-clojure.logic
 clojure.test-clojure.macros
 clojure.test-clojure.main
diff --git a/test/clojure/test_clojure/load.clj b/test/clojure/test_clojure/load.clj
new file mode 100644
index 00000000..31f3c39e
--- /dev/null
+++ b/test/clojure/test_clojure/load.clj
@@ -0,0 +1,21 @@
+;   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.
+
+(ns clojure.test-clojure.load
+  (:use clojure.test))
+
+(deftest test-load
+  (testing "Should ignore self-loads without comment"
+    (is (nil? (require 'clojure.test-clojure.load.cyclic0))))
+  (testing "Should reject cyclic dependencies"
+    (testing "a->b->a"
+      (is (thrown-with-msg? Exception #".*Cyclic load dependency.*"
+            (require 'clojure.test-clojure.load.cyclic1))))
+    (testing "a->b->c->d->b"
+      (is (thrown-with-msg? Exception #".*Cyclic load dependency.*"
+            (require 'clojure.test-clojure.load.cyclic3))))))
diff --git a/test/clojure/test_clojure/load/cyclic0.clj b/test/clojure/test_clojure/load/cyclic0.clj
new file mode 100644
index 00000000..66a3cc10
--- /dev/null
+++ b/test/clojure/test_clojure/load/cyclic0.clj
@@ -0,0 +1,12 @@
+;   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.
+;
+; Author: Stephen C. Gilardi
+
+(ns clojure.test-clojure.load.cyclic0
+  (:require clojure.test-clojure.load.cyclic0))
diff --git a/test/clojure/test_clojure/load/cyclic1.clj b/test/clojure/test_clojure/load/cyclic1.clj
new file mode 100644
index 00000000..bf341f7b
--- /dev/null
+++ b/test/clojure/test_clojure/load/cyclic1.clj
@@ -0,0 +1,12 @@
+;   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.
+;
+; Author: Stephen C. Gilardi
+
+(ns clojure.test-clojure.load.cyclic1
+  (:require clojure.test-clojure.load.cyclic2))
diff --git a/test/clojure/test_clojure/load/cyclic2.clj b/test/clojure/test_clojure/load/cyclic2.clj
new file mode 100644
index 00000000..180a1620
--- /dev/null
+++ b/test/clojure/test_clojure/load/cyclic2.clj
@@ -0,0 +1,12 @@
+;   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.
+;
+; Author: Stephen C. Gilardi
+
+(ns clojure.test-clojure.load.cyclic2
+  (:require clojure.test-clojure.load.cyclic1))
diff --git a/test/clojure/test_clojure/load/cyclic3.clj b/test/clojure/test_clojure/load/cyclic3.clj
new file mode 100644
index 00000000..51a8e454
--- /dev/null
+++ b/test/clojure/test_clojure/load/cyclic3.clj
@@ -0,0 +1,12 @@
+;   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.
+;
+; Author: Stephen C. Gilardi
+
+(ns clojure.test-clojure.load.cyclic3
+  (:require clojure.test-clojure.load.cyclic4))
diff --git a/test/clojure/test_clojure/load/cyclic4.clj b/test/clojure/test_clojure/load/cyclic4.clj
new file mode 100644
index 00000000..d66a0fce
--- /dev/null
+++ b/test/clojure/test_clojure/load/cyclic4.clj
@@ -0,0 +1,12 @@
+;   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.
+;
+; Author: Stephen C. Gilardi
+
+(ns clojure.test-clojure.load.cyclic4
+  (:require clojure.test-clojure.load.cyclic5))
diff --git a/test/clojure/test_clojure/load/cyclic5.clj b/test/clojure/test_clojure/load/cyclic5.clj
new file mode 100644
index 00000000..e825b745
--- /dev/null
+++ b/test/clojure/test_clojure/load/cyclic5.clj
@@ -0,0 +1,12 @@
+;   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.
+;
+; Author: Stephen C. Gilardi
+
+(ns clojure.test-clojure.load.cyclic5
+  (:require clojure.test-clojure.load.cyclic6))
diff --git a/test/clojure/test_clojure/load/cyclic6.clj b/test/clojure/test_clojure/load/cyclic6.clj
new file mode 100644
index 00000000..d607f052
--- /dev/null
+++ b/test/clojure/test_clojure/load/cyclic6.clj
@@ -0,0 +1,12 @@
+;   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.
+;
+; Author: Stephen C. Gilardi
+
+(ns clojure.test-clojure.load.cyclic6
+  (:require clojure.test-clojure.load.cyclic4))