fixed an issue where setting the alpha after creating the color causes all colors referencing that color in the cache to have their alpha value changed

AppKit/CoreGraphics/CGColor.j

@@ -150,19 +150,21 @@ function CGColorCreateGenericCMYK(cyan, magenta, yellow, black, alpha)
 */
 function CGColorCreateCopyWithAlpha(aColor, anAlpha)
 {
-    var components = aColor.components;
+    if ( !aColor ) return aColor; // Avoid error null pointer in next line
 
-    if (!aColor || anAlpha == components[components.length - 1])
+    var components = aColor.components.slice();
+
+    if (anAlpha == components[components.length - 1])
         return aColor;
 
+    // set new alpha value now so that a potentially a new cache entry is made and
+    // not that an existing cache entry is mutated.
+    components[components.length - 1] = anAlpha;
+
     if (aColor.pattern)
-        var copy = CGColorCreateWithPattern(aColor.colorspace, aColor.pattern, components);
+        return CGColorCreateWithPattern(aColor.colorspace, aColor.pattern, components);
     else
-        var copy = CGColorCreate(aColor.colorspace, components);
-
-    copy.components[components.length - 1] = anAlpha;
-
-    return copy;
+        return CGColorCreate(aColor.colorspace, components);
 }
 
 /*!

Tests/AppKit/CGColorTest.j

@@ -2,6 +2,33 @@
 
 @implementation CGColorTest : OJTestCase
 
+- (void)testColorCreateReturnNullIfNull
+{
+    [self assert:NULL equals:CGColorCreate( NULL, [1,2,3] ) message:"colorspace null failed"];
+    [self assert:NULL 
+          equals:CGColorCreate( CGColorSpaceCreateDeviceRGB(), NULL ) 
+          message:"components null failed"];
+}
+
+- (void)testColorCreateEnsureComponentsAreCopied
+{
+    var colorspace = CGColorSpaceCreateDeviceRGB(), 
+        components = [2,3,4,5],
+        clr = CGColorCreate(colorspace, components);
+
+    components[0] = components[1] = components[2] = components[3] = 0;
+    [self assert:[1,1,1,1] equals:clr.components];
+    [self assert:[0,0,0,0] equals:components];
+}
+
+- (void)testColorCreateCachesColorsAlphaChangeIsPropagated
+{
+    var clr = CGColorCreate(CGColorSpaceCreateDeviceRGB(), [0.4, 0.3, 0.2, 0.2]),
+        newclr = CGColorCreate(CGColorSpaceCreateDeviceRGB(), [0.4, 0.3, 0.2, 0.2]);
+    newclr.components[newclr.components.length - 1] = 0.6;
+    [self assert:0.6 equals:clr.components[clr.components.length-1]];
+}
+
 - (void)testColorCreate
 {
     var colorspace = CGColorSpaceCreateDeviceRGB(), 
@@ -63,5 +90,119 @@
     [self assert:NULL equals:clr.pattern message:"pattern failed"];
 }
 
+- (void)testColorCreateWithPattern
+{
+    var clrspc = CGColorSpaceCreateDeviceRGB(),
+        pattern = "a new pattern",
+        components = [0.2, 0.4, 0.6, 0.8],
+        clr = CGColorCreateWithPattern(clrspc, pattern, components);
+
+    [self assert:clrspc equals:clr.colorspace];
+    [self assert:pattern equals:clr.pattern];
+    [self assert:components equals:clr.components];
+
+    // ensure that there was a copy made of the components
+    components[0] = components[1] = components[2] = components[3] = 0.0;
+    [self assert:[0.2, 0.4, 0.6, 0.8] equals:clr.components];
+
+    // ensure that null is returned
+    [self assert:NULL equals:CGColorCreateWithPattern(NULL, "a new pattern", [])];
+    [self assert:NULL equals:CGColorCreateWithPattern(CGColorSpaceCreateDeviceRGB(), 
+                                                      NULL, [])];
+    [self assert:NULL equals:CGColorCreateWithPattern(CGColorSpaceCreateDeviceRGB(), 
+                                                      "a new pattern", NULL)];
+    [self assert:NULL equals:CGColorCreateWithPattern(NULL, NULL, NULL)];
+}
+
+- (void)testColorGetAlpha
+{
+    var clr = CGColorCreateGenericCMYK(0.2, 0.3, 0.4, 0.5, 0.6);
+    [self assert:0.6 equals:CGColorGetAlpha(clr)];
+}
+
+- (void)testColorGetColorSpace
+{
+    var clr = CGColorCreateGenericCMYK(0.2, 0.3, 0.4, 0.5, 0.6);
+    [self assert:CGColorSpaceCreateDeviceCMYK()
+          equals:CGColorGetColorSpace(clr)];
+}
+
+- (void)testColorGetComponents
+{
+    var clr = CGColorCreateGenericCMYK(0.2, 0.3, 0.4, 0.5, 0.6);
+    [self assert:[ROUND(0.2*255)/255, ROUND(0.3*255)/255, ROUND(0.4*255)/255,
+                  ROUND(0.5*255)/255, ROUND(0.6*255)/255] 
+          equals:CGColorGetComponents(clr)];
+}
+
+- (void)testColorGetNumberOfComponents
+{
+    var clr = CGColorCreateGenericCMYK(0.2, 0.3, 0.4, 0.5, 0.6);
+    [self assert:5 equals:CGColorGetNumberOfComponents(clr)];
+}
+
+- (void)testColorGetPattern
+{
+    var clr = CGColorCreateWithPattern(CGColorSpaceCreateDeviceRGB(), "a new pattern",
+                                       [1,1,1,1]);
+    [self assert:"a new pattern" equals:CGColorGetPattern(clr)];
+}
+
+- (void)testColorCreateCopyWithAlphaWithPattern
+{
+    var clr = CGColorCreateWithPattern(CGColorSpaceCreateDeviceRGB(), "a new pattern",
+                                       [1,1,1,1]);
+    [self assert:1 equals:CGColorGetAlpha(clr) message:"initial alpha"];
+    
+    var newclr = CGColorCreateCopyWithAlpha(clr, 0.6);
+    [self assert:0.6 equals:CGColorGetAlpha(newclr) message:"new color alpha value"];
+    [self assert:1 equals:CGColorGetAlpha(clr) message:"alpha after copy"];
+
+    [self assert:clr.colorspace equals:newclr.colorspace message:"newclr colorspace failed"];
+    [self assert:clr.pattern equals:newclr.pattern message:"newclr pattern failed"];
+}
+
+- (void)testColorCreateCopyWithAlphaWithComponents
+{
+    var clr = CGColorCreateGenericRGB(0.4, 0.3, 0.2, 0.3);
+    [self assert:0.3 equals:CGColorGetAlpha(clr) message:"initial alpha"];
+
+    var newclr = CGColorCreateCopyWithAlpha(clr, 0.6);
+    [self assert:0.6 equals:CGColorGetAlpha(newclr) message:"new color alpha value"];
+    [self assert:0.3 equals:CGColorGetAlpha(clr) message:"alpha after copy"];
+
+    [self assert:CGColorSpaceCreateDeviceRGB()
+          equals:newclr.colorspace message:"newclr colorspace failed"];
+    [self assert:[ROUND(0.4*255)/255,ROUND(0.3*255)/255,ROUND(0.2*255)/255,0.6]
+          equals:newclr.components message:"newclr components failed"];
+    [self assert:NULL equals:newclr.pattern message:"newclr pattern failed"];
+
+    [self assert:CGColorSpaceCreateDeviceRGB()
+          equals:clr.colorspace message:"orig clr colorspace failed"];
+    [self assert:[ROUND(0.4*255)/255,ROUND(0.3*255)/255,ROUND(0.2*255)/255,0.3]
+          equals:clr.components message:"orig clr components failed"];
+    [self assert:NULL equals:clr.pattern message:"orig clr pattern failed"];
+}
+
+- (void)testColorCreateCopyWithAlphaWithComponentsNullColor
+{
+    [self assert:NULL 
+          equals:CGColorCreateCopyWithAlpha(NULL,0.5)
+          message:"null color failed"];
+
+    var clr = CGColorCreateGenericRGB(0.4,0.3,0.2,0.1),
+        newclr = CGColorCreateCopyWithAlpha(clr, 0.1);
+    [self assert:clr equals:newclr];
+}
+
+- (void)testColorEqualToColor
+{
+    var clr1 = CGColorCreateGenericRGB(0.4, 0.3, 0.2, 0.3);
+    [self assert:true equals:CGColorEqualToColor(NULL,NULL)];
+    [self assert:false equals:CGColorEqualToColor(NULL,clr1)];
+    [self assert:true equals:CGColorEqualToColor(clr1,clr1)];
+    [self assert:false equals:CGColorEqualToColor(clr1,NULL)];
+}
+
 @end