Backout Bug 704259, a=bustage

js/src/jsapi.cpp

@@ -6467,10 +6467,23 @@ JS_ClearPendingException(JSContext *cx)
 JS_PUBLIC_API(JSBool)
 JS_ReportPendingException(JSContext *cx)
 {
+    JSBool ok;
+    bool save;
+
     AssertNoGC(cx);
     CHECK_REQUEST(cx);
 
-    return js_ReportUncaughtException(cx);
+    /*
+     * Set cx->generatingError to suppress the standard error-to-exception
+     * conversion done by all {js,JS}_Report* functions except for OOM.  The
+     * cx->generatingError flag was added to suppress recursive divergence
+     * under js_ErrorToException, but it serves for our purposes here too.
+     */
+    save = cx->generatingError;
+    cx->generatingError = JS_TRUE;
+    ok = js_ReportUncaughtException(cx);
+    cx->generatingError = save;
+    return ok;
 }
 
 struct JSExceptionState {

js/src/jscntxt.h

@@ -830,11 +830,11 @@ struct JSContext : js::ContextFriendFields
     bool                hasVersionOverride;
 
     /* Exception state -- the exception member is a GC root by definition. */
-    JSBool              throwing;            /* is there a pending exception? */
-    js::Value           exception;           /* most-recently-thrown exception */
+    JSBool              throwing;           /* is there a pending exception? */
+    js::Value           exception;          /* most-recently-thrown exception */
 
     /* Per-context run options. */
-    unsigned            runOptions;          /* see jsapi.h for JSOPTION_* */
+    unsigned               runOptions;            /* see jsapi.h for JSOPTION_* */
 
   public:
     int32_t             reportGranularity;  /* see jsprobes.h */
@@ -844,8 +844,11 @@ struct JSContext : js::ContextFriendFields
 
     js::AutoResolving   *resolvingList;
 
-    /* True if generating an error, to prevent runaway recursion. */
-    bool                generatingError;
+    /*
+     * True if generating an error, to prevent runaway recursion.
+     * NB: generatingError packs with throwing below.
+     */
+    bool        generatingError;
 
     /* GC heap compartment. */
     JSCompartment       *compartment;

js/src/jsexn.cpp

@@ -1084,7 +1084,7 @@ js_ErrorToException(JSContext *cx, const char *message, JSErrorReport *reportp,
      */
     JS_ASSERT(reportp);
     if (JSREPORT_IS_WARNING(reportp->flags))
-        return false;
+        return JS_FALSE;
 
     /* Find the exception index associated with this error. */
     errorNumber = (JSErrNum) reportp->errorNumber;
@@ -1107,12 +1107,19 @@ js_ErrorToException(JSContext *cx, const char *message, JSErrorReport *reportp,
      * with the given error number.
      */
     if (exn == JSEXN_NONE)
-        return false;
+        return JS_FALSE;
 
-    /* Prevent infinite recursion. */
+    /*
+     * Prevent runaway recursion, via cx->generatingError.  If an out-of-memory
+     * error occurs, no exception object will be created, but we don't assume
+     * that OOM is the only kind of error that subroutines of this function
+     * called below might raise.
+     */
     if (cx->generatingError)
-        return false;
-    AutoScopedAssign<bool> asa(&cx->generatingError, false);
+        return JS_FALSE;
+
+    MUST_FLOW_THROUGH("out");
+    cx->generatingError = JS_TRUE;
 
     /* Protect the newly-created strings below from nesting GCs. */
     PodArrayZero(tv);
@@ -1125,34 +1132,43 @@ js_ErrorToException(JSContext *cx, const char *message, JSErrorReport *reportp,
      */
     ok = js_GetClassPrototype(cx, NULL, GetExceptionProtoKey(exn), &errProto);
     if (!ok)
-        return false;
+        goto out;
     tv[0] = OBJECT_TO_JSVAL(errProto);
 
     errObject = NewObjectWithGivenProto(cx, &ErrorClass, errProto, NULL);
-    if (!errObject)
-        return false;
+    if (!errObject) {
+        ok = JS_FALSE;
+        goto out;
+    }
     tv[1] = OBJECT_TO_JSVAL(errObject);
 
     messageStr = JS_NewStringCopyZ(cx, message);
-    if (!messageStr)
-        return false;
+    if (!messageStr) {
+        ok = JS_FALSE;
+        goto out;
+    }
     tv[2] = STRING_TO_JSVAL(messageStr);
 
     filenameStr = JS_NewStringCopyZ(cx, reportp->filename);
-    if (!filenameStr)
-        return false;
+    if (!filenameStr) {
+        ok = JS_FALSE;
+        goto out;
+    }
     tv[3] = STRING_TO_JSVAL(filenameStr);
 
     ok = InitExnPrivate(cx, errObject, messageStr, filenameStr,
                         reportp->lineno, reportp, exn);
     if (!ok)
-        return false;
+        goto out;
 
     JS_SetPendingException(cx, OBJECT_TO_JSVAL(errObject));
 
     /* Flag the error report passed in to indicate an exception was raised. */
     reportp->flags |= JSREPORT_EXCEPTION;
-    return true;
+
+out:
+    cx->generatingError = JS_FALSE;
+    return ok;
 }
 
 JSBool