I just fixed a bug in the compiler, and now we are getting more of these
implicit coercion errors because the recent Google Closure Typedefs now specify
interfaces as parameters to certain contructors (or maybe they always did and
the compiler is now getting better at catching these errors).
Code that looked like:
var blob:Blob = new Blob([text], { type: 'text/plain' });
or
customEvent = new window.Event(type, {bubbles: bubbles, cancelable:
cancelable});
now results in a compiler error because the plain objects don't implement
whatever interface of properties the constructor expects. I think Google
Closure did this so that the properties in the plain object don't get renamed
by the minifier.
One solution, that Yishay tried in this commit was simply to lie to the
compiler and tell it that the plain object was a BlobPropertyBag. And while
that is the "least amount of code" solution, I didn’t like that solution
because it looks funny to have lots of places in our code where a plain object
is coerced to a type.
So, I went and created classes that implement BlobPropertyBag and other
interfaces. I didn't like adding the weight of additional class definitions
but the classes I did were small, just a couple of properties. However, for
Event,there is a pretty big list of properties just to specify bubbles and
cancelable. The compiler was not catching that plain object before, but now
with the fix I just made it will. And I’m not sure it is worth adding a large
class with lots of properties.
So, I thought of a third idea which is a hack between what Yishay tried and the
interface implementations I did, which is to have a factory that returns an
instance of the interface, but actually returns a plain object. As long as no
code actually tests that the instance implements the interface, it should work.
And that would localize the coercion of a plain object to an interface in
relatively few known places in our code.
The pattern would be to create a top-level factory function() unless it makes
sense to add it to a class so for Blob it might look like:
/**
* @royaleignorecoercion BlobPropertyBag
*/
public function createBlobPropertyBag():BlobPropertyBag
{
// return a plain object but fool the compiler into thinking it is an
implementation of the interface
return {} as BlobPropertyBag;
}
IMO, this also future-proofs the code in case we ever run where there is
runtime type-checking and need to someday return a real concrete instance that
implements the interface.
Thoughts?
-Alex
On 12/26/18, 11:02 PM, "Yishay Weiss" <[email protected]> wrote:
Sounds good, feel free to revert.
________________________________
From: Alex Harui <[email protected]>
Sent: Thursday, December 27, 2018 3:43:45 AM
To: [email protected]; [email protected]
Subject: Re: [royale-asjs] branch develop updated: Fix implicit coercion
error
I don't think we should hack it like this. Casting a plain object to a
type makes the code look strange, and it might not minify correctly. I have a
different fix I hope to put in shortly where we actually pass in an instance of
the BlogPropertyBag.
-Alex
On 12/26/18, 6:57 AM, "[email protected]" <[email protected]> wrote:
This is an automated email from the ASF dual-hosted git repository.
yishayw pushed a commit to branch develop
in repository
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgitbox.apache.org%2Frepos%2Fasf%2Froyale-asjs.git&data=02%7C01%7Caharui%40adobe.com%7C00f548a683d34a9c88b508d66bc93265%7Cfa7b1b5a7b34438794aed2c178decee1%7C0%7C0%7C636814909228765885&sdata=5DaM3aljpj1rk4FD0KBSzLWrfi9jzCOmbnAvfy2me8o%3D&reserved=0
The following commit(s) were added to refs/heads/develop by this push:
new 2f127d4 Fix implicit coercion error
2f127d4 is described below
commit 2f127d459ee807f197950e11af947c623c270369
Author: DESKTOP-RH4S838\Yishay <[email protected]>
AuthorDate: Wed Dec 26 16:57:33 2018 +0200
Fix implicit coercion error
---
.../src/main/royale/org/apache/royale/storage/file/DataOutputStream.as
| 2 +-
.../apache/royale/storage/providers/AndroidExternalStorageProvider.as
| 2 +-
.../royale/org/apache/royale/storage/providers/WebStorageProvider.as
| 2 +-
3 files changed, 3 insertions(+), 3 deletions(-)
diff --git
a/frameworks/projects/Storage/src/main/royale/org/apache/royale/storage/file/DataOutputStream.as
b/frameworks/projects/Storage/src/main/royale/org/apache/royale/storage/file/DataOutputStream.as
index cff76eb..55eab71 100644
---
a/frameworks/projects/Storage/src/main/royale/org/apache/royale/storage/file/DataOutputStream.as
+++
b/frameworks/projects/Storage/src/main/royale/org/apache/royale/storage/file/DataOutputStream.as
@@ -117,7 +117,7 @@ public class DataOutputStream extends
EventDispatcher implements IDataOutput
public function writeText(text:String):void
{
COMPILE::JS {
- var blob:Blob = new Blob([text], { type:
'text/plain' });
+ var blob:Blob = new Blob([text], { type:
'text/plain' } as BlobPropertyBag);
_fileWriter.write(blob);
}
COMPILE::SWF {
diff --git
a/frameworks/projects/Storage/src/main/royale/org/apache/royale/storage/providers/AndroidExternalStorageProvider.as
b/frameworks/projects/Storage/src/main/royale/org/apache/royale/storage/providers/AndroidExternalStorageProvider.as
index ea79a5b..cf05a73 100644
---
a/frameworks/projects/Storage/src/main/royale/org/apache/royale/storage/providers/AndroidExternalStorageProvider.as
+++
b/frameworks/projects/Storage/src/main/royale/org/apache/royale/storage/providers/AndroidExternalStorageProvider.as
@@ -199,7 +199,7 @@ package org.apache.royale.storage.providers
_target.dispatchEvent(newEvent);
};
- var blob:Blob = new
Blob([text], { type: 'text/plain' });
+ var blob:Blob = new
Blob([text], { type: 'text/plain' } as BlobPropertyBag);
fileWriter.write(blob);
}, function(e):void {
var
errEvent:FileErrorEvent = new FileErrorEvent("ERROR");
diff --git
a/frameworks/projects/Storage/src/main/royale/org/apache/royale/storage/providers/WebStorageProvider.as
b/frameworks/projects/Storage/src/main/royale/org/apache/royale/storage/providers/WebStorageProvider.as
index 1632bfa..dd9c84c 100644
---
a/frameworks/projects/Storage/src/main/royale/org/apache/royale/storage/providers/WebStorageProvider.as
+++
b/frameworks/projects/Storage/src/main/royale/org/apache/royale/storage/providers/WebStorageProvider.as
@@ -199,7 +199,7 @@ package org.apache.royale.storage.providers
_target.dispatchEvent(newEvent);
};
- var blob:Blob = new
Blob([text], { type: 'text/plain' });
+ var blob:Blob = new
Blob([text], { type: 'text/plain' } as BlobPropertyBag);
fileWriter.write(blob);
}, function(e):void {
var
errEvent:FileErrorEvent = new FileErrorEvent("ERROR");
