From 7bd2eb8c44e35c9df5b8e81188ce7129d1ca3ef3 Mon Sep 17 00:00:00 2001
From: RBRi <rbri@rbri.de>
Date: Tue, 3 May 2022 05:11:54 +0200
Subject: [PATCH] improve log output of Callable's (#1213)

Change console output to print output identifying Callables and other function objects using some identifying text and not just "null".

Fixes https://github.com/mozilla/rhino/pull/1213
---
 src/org/mozilla/javascript/NativeConsole.java | 29 ++++++++++++++++++-
 .../javascript/tests/NativeConsoleTest.java   | 16 ++++++++++
 2 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/src/org/mozilla/javascript/NativeConsole.java b/src/org/mozilla/javascript/NativeConsole.java
index 08223d8887..c709ff1616 100644
--- a/src/org/mozilla/javascript/NativeConsole.java
+++ b/src/org/mozilla/javascript/NativeConsole.java
@@ -325,7 +325,34 @@ private static String formatObj(Context cx, Scriptable scope, Object arg) {
         }
 
         try {
-            Object stringify = NativeJSON.stringify(cx, scope, arg, null, null);
+            // NativeJSON.stringify outputs Callable's as null, convert to string
+            // to make the output less confusing
+            final Callable replacer =
+                    new Callable() {
+                        @Override
+                        public Object call(
+                                Context callCx,
+                                Scriptable callScope,
+                                Scriptable callThisObj,
+                                Object[] callArgs) {
+                            Object value = callArgs[1];
+                            while (value instanceof Delegator) {
+                                value = ((Delegator) value).getDelegee();
+                            }
+                            if (value instanceof BaseFunction) {
+                                StringBuilder sb = new StringBuilder();
+                                sb.append("function ")
+                                        .append(((BaseFunction) value).getFunctionName())
+                                        .append("() {...}");
+                                return sb.toString();
+                            }
+                            if (value instanceof Callable) {
+                                return ScriptRuntime.toString(value);
+                            }
+                            return value;
+                        }
+                    };
+            Object stringify = NativeJSON.stringify(cx, scope, arg, replacer, null);
             return ScriptRuntime.toString(stringify);
         } catch (EcmaError e) {
             if ("TypeError".equals(e.getName())) {
diff --git a/testsrc/org/mozilla/javascript/tests/NativeConsoleTest.java b/testsrc/org/mozilla/javascript/tests/NativeConsoleTest.java
index 81284baecd..daa5943a5e 100644
--- a/testsrc/org/mozilla/javascript/tests/NativeConsoleTest.java
+++ b/testsrc/org/mozilla/javascript/tests/NativeConsoleTest.java
@@ -361,6 +361,22 @@ public void print() {
         assertPrintMsg("console.error('abc', 123)", "abc 123");
     }
 
+    @Test
+    public void printCallable() {
+        String js = "function foo() {}\n console.log(foo)";
+        assertPrintMsg(js, "\"function foo() {...}\"");
+
+        // suppress body
+        js = "function fooo() { var i = 0; }\n console.log(fooo)";
+        assertPrintMsg(js, "\"function fooo() {...}\"");
+
+        js = "console.log(/abc/i)";
+        assertPrintMsg(js, "\"/abc/i\"");
+
+        js = "function foo() {}\n" + "console.log([foo, /abc/])";
+        assertPrintMsg(js, "[\"function foo() {...}\",\"/abc/\"]");
+    }
+
     @Test
     public void trace() {
         assertPrintMsg(