Bug 528414 - JS_IsRunning can be wrong. r=brendan.

--HG--
extra : rebase_source : 4fca5efd5f558c1b64b0e86580d2c42af7e61e34

js/src/jsapi-tests/Makefile.in

@@ -48,6 +48,7 @@ PROGRAM         = jsapi-tests$(BIN_SUFFIX)
 CPPSRCS = \
   tests.cpp \
   selfTest.cpp \
+  testContexts.cpp \
   testDefineGetterSetterNonEnumerable.cpp \
   testIntString.cpp \
   testLookup.cpp \

js/src/jsapi-tests/testContexts.cpp

@@ -0,0 +1,26 @@
+#include "tests.h"
+
+BEGIN_TEST(testContexts_IsRunning)
+    {
+        CHECK(JS_DefineFunction(cx, global, "chk", chk, 0, 0));
+        EXEC("for (var i = 0; i < 9; i++) chk();");
+        return true;
+    }
+
+    static JSBool chk(JSContext *cx, JSObject *obj, uintN argc, jsval *argv, jsval *rval)
+    {
+        JSRuntime *rt = JS_GetRuntime(cx);
+        JSContext *acx = JS_NewContext(rt, 8192);
+        if (!acx) {
+            JS_ReportOutOfMemory(cx);
+            return JS_FALSE;
+        }
+
+        // acx should not be running
+        bool ok = !JS_IsRunning(acx);
+        if (!ok)
+            JS_ReportError(cx, "Assertion failed: brand new context claims to be running");
+        JS_DestroyContext(acx);
+        return ok;
+    }
+END_TEST(testContexts_IsRunning)

js/src/jsapi.cpp

@@ -5140,10 +5140,17 @@ JS_TriggerAllOperationCallbacks(JSRuntime *rt)
 JS_PUBLIC_API(JSBool)
 JS_IsRunning(JSContext *cx)
 {
-    /* The use of cx->fp below is safe: if we're on trace, it is skipped. */
+    /*
+     * The use of cx->fp below is safe. Rationale: Here we don't care if the
+     * interpreter state is stale. We just want to know if there *is* any
+     * interpreter state.
+     */
     VOUCH_DOES_NOT_REQUIRE_STACK();
 
-    return JS_ON_TRACE(cx) || cx->fp != NULL;
+#ifdef JS_TRACER
+    JS_ASSERT_IF(JS_TRACE_MONITOR(cx).tracecx == cx, cx->fp);
+#endif
+    return cx->fp != NULL;
 }
 
 JS_PUBLIC_API(JSBool)