Support option to specify array length of zero to force pointer comparison.

docs/UnityConfigurationGuide.md

@@ -121,6 +121,12 @@ _Example:_
 #define UNITY_POINTER_WIDTH 64 // Set UNITY_POINTER_WIDTH to 64-bit
 ```
 
+#### `UNITY_COMPARE_PTRS_ON_ZERO_ARRAY`
+
+Define this to make all array assertions compare pointers instead of contents when a length of zero is specified. When not enabled,
+defining a length of zero will always result in a failure and a message warning the user that they have tried to compare empty
+arrays.
+
 #### `UNITY_SUPPORT_64`
 
 Unity will automatically include 64-bit support if it auto-detects it, or if your `int`, `long`, or pointer widths are greater than 32-bits.

src/unity.c

@@ -796,7 +796,11 @@ void UnityAssertEqualIntArray(UNITY_INTERNAL_PTR expected,
 
     if (num_elements == 0)
     {
+#ifdef UNITY_COMPARE_PTRS_ON_ZERO_ARRAY
+        UNITY_TEST_ASSERT_EQUAL_PTR(expected, actual, lineNumber, msg);
+#else
         UnityPrintPointlessAndBail();
+#endif
     }
 
     if (expected == actual)
@@ -943,7 +947,11 @@ void UnityAssertEqualFloatArray(UNITY_PTR_ATTRIBUTE const UNITY_FLOAT* expected,
 
     if (elements == 0)
     {
+#ifdef UNITY_COMPARE_PTRS_ON_ZERO_ARRAY
+        UNITY_TEST_ASSERT_EQUAL_PTR(expected, actual, lineNumber, msg);
+#else
         UnityPrintPointlessAndBail();
+#endif
     }
 
     if (expected == actual)
@@ -1084,7 +1092,11 @@ void UnityAssertEqualDoubleArray(UNITY_PTR_ATTRIBUTE const UNITY_DOUBLE* expecte
 
     if (elements == 0)
     {
+#ifdef UNITY_COMPARE_PTRS_ON_ZERO_ARRAY
+        UNITY_TEST_ASSERT_EQUAL_PTR(expected, actual, lineNumber, msg);
+#else
         UnityPrintPointlessAndBail();
+#endif
     }
 
     if (expected == actual)
@@ -1265,7 +1277,11 @@ void UnityAssertNumbersArrayWithin(const UNITY_UINT delta,
 
     if (num_elements == 0)
     {
+#ifdef UNITY_COMPARE_PTRS_ON_ZERO_ARRAY
+        UNITY_TEST_ASSERT_EQUAL_PTR(expected, actual, lineNumber, msg);
+#else
         UnityPrintPointlessAndBail();
+#endif
     }
 
     if (expected == actual)
@@ -1504,7 +1520,11 @@ void UnityAssertEqualStringArray(UNITY_INTERNAL_PTR expected,
     /* if no elements, it's an error */
     if (num_elements == 0)
     {
+#ifdef UNITY_COMPARE_PTRS_ON_ZERO_ARRAY
+        UNITY_TEST_ASSERT_EQUAL_PTR(expected, actual, lineNumber, msg);
+#else
         UnityPrintPointlessAndBail();
+#endif
     }
 
     if ((const void*)expected == (const void*)actual)
@@ -1581,7 +1601,15 @@ void UnityAssertEqualMemory(UNITY_INTERNAL_PTR expected,
 
     RETURN_IF_FAIL_OR_IGNORE;
 
-    if ((elements == 0) || (length == 0))
+    if (elements == 0)
+    {
+#ifdef UNITY_COMPARE_PTRS_ON_ZERO_ARRAY
+        UNITY_TEST_ASSERT_EQUAL_PTR(expected, actual, lineNumber, msg);
+#else
+        UnityPrintPointlessAndBail();
+#endif
+    }
+    if (length == 0)
     {
         UnityPrintPointlessAndBail();
     }

src/unity_internals.h

@@ -214,6 +214,8 @@
   #define UNITY_INTERNAL_PTR UNITY_PTR_ATTRIBUTE const void*
 #endif
 
+/* optionally define UNITY_COMPARE_PTRS_ON_ZERO_ARRAY */
+
 /*-------------------------------------------------------
  * Float Support
  *-------------------------------------------------------*/

test/targets/clang_strict.yml

@@ -69,3 +69,4 @@ colour: true
   - UNITY_INCLUDE_DOUBLE
   - UNITY_SUPPORT_TEST_CASES
   - UNITY_SUPPORT_64
+  - UNITY_COMPARE_PTRS_ON_ZERO_ARRAY

test/tests/test_unity_arrays.c

@@ -2908,3 +2908,33 @@ void testNotEqualInt64Arrays(void)
     VERIFY_FAILS_END
 #endif
 }
+
+void testVerifyIntPassingPointerComparisonOnZeroLengthArray(void)
+{
+    int a[] = { 1 };
+
+#ifndef UNITY_COMPARE_PTRS_ON_ZERO_ARRAY
+    EXPECT_ABORT_BEGIN
+    TEST_ASSERT_EQUAL_INT_ARRAY(a, a, 0);
+    VERIFY_FAILS_END
+#else
+
+    TEST_ASSERT_EQUAL_INT_ARRAY(a, a, 0);
+#endif
+}
+
+void testVerifyIntFailingPointerComparisonOnZeroLengthArray(void)
+{
+    int a[] = { 1 };
+    int b[] = { 1 };
+
+#ifndef UNITY_COMPARE_PTRS_ON_ZERO_ARRAY
+    EXPECT_ABORT_BEGIN
+    TEST_ASSERT_EQUAL_INT_ARRAY(a, b, 0);
+    VERIFY_FAILS_END
+#else
+    EXPECT_ABORT_BEGIN
+    TEST_ASSERT_EQUAL_INT_ARRAY(a, b, 0);
+    VERIFY_FAILS_END
+#endif
+}