[Closure Externs] Handle optional params sent to an API callback

[Closure Externs] Handle optional params sent to an API callback

An API might conditionally send a response parameter to a caller.
e.g., envision an API:
doStuff({includeResult: true})
which responds with a Result iff includeResult was present and true.

Currently, closure extern generation doesn't handle this case well,
and for a callback like:

callback FooCallback = void(optional FooResponse response);
static void doStuff(DoStuffParams params, FooCallback callback);

generates:

/**
 * @param {DoStuffParams} params
 * @param {function(!FooResponse):void} callback
 */

But this is incorrect, since it indicates that the response would
never be null.

Properly handle these optional responses, and update the test.

BUG=704242
Review-Url: https://codereview.chromium.org/2766363002
Cr-Commit-Position: refs/heads/master@{#458876}
Committed: https://chromium.googlesource.com/chromium/src/+/f9c093e54e11cb41c6f3402997a97be16568865f

[Devlin, 2017-03-22 18:56:54]

The CQ bit was checked by rdevlin.cronin@chromium.org to run a CQ dry run

[Devlin, 2017-03-22 18:56:59]

rdevlin.cronin@chromium.org changed reviewers:
+ lazyboy@chromium.org

[commit-bot: I haz the power, 2017-03-22 18:57:47]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-03-22 19:07:30]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-03-22 19:07:30]

Dry run: This issue passed the CQ dry run.

[lazyboy, 2017-03-22 21:04:32]

lgtm

You need to fix the CL description:
 * @param {function(!FooResponse):void} callback

to 
 * @param {function(!FooResponse):void=} callback
______________________________________^____

|callback| correctly marks being optional, right?

[Devlin, 2017-03-22 21:05:51]

On 2017/03/22 21:04:32, lazyboy wrote:
> lgtm
> 
> You need to fix the CL description:
>  * @param {function(!FooResponse):void} callback
> 
> to 
>  * @param {function(!FooResponse):void=} callback
> ______________________________________^____
> 
> |callback| correctly marks being optional, right?

Yes, but only if the callback itself was specified as optional, which wasn't
specified in the description. :)  I'll expand to make it clear.

[Devlin, 2017-03-22 21:06:41]

Description was changed from

==========
[Closure Externs] Handle optional params sent to an API callback

An API might conditionally send a response parameter to a caller.
e.g., envision an API:
doStuff({includeResult: true})
which responds with a Result iff includeResult was present and true.

Currently, closure extern generation doesn't handle this case well,
and for a callback like:

callback FooCallback = void(optional FooResponse response);

generates:

/**
 * @param {function(!FooResponse):void} callback
 */

But this is incorrect, since it indicates that the response would
never be null.

Properly handle these optional responses, and update the test.

BUG=704242
==========

to

==========
[Closure Externs] Handle optional params sent to an API callback

An API might conditionally send a response parameter to a caller.
e.g., envision an API:
doStuff({includeResult: true})
which responds with a Result iff includeResult was present and true.

Currently, closure extern generation doesn't handle this case well,
and for a callback like:

callback FooCallback = void(optional FooResponse response);
static void doStuff(DoStuffParams params, FooCallback callback);

generates:

/**
 * @param {DoStuffParams} params
 * @param {function(!FooResponse):void} callback
 */

But this is incorrect, since it indicates that the response would
never be null.

Properly handle these optional responses, and update the test.

BUG=704242
==========

[Devlin, 2017-03-22 21:06:50]

The CQ bit was checked by rdevlin.cronin@chromium.org

[commit-bot: I haz the power, 2017-03-22 21:07:53]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-03-22 21:13:27]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1490216810758690, "parent_rev":
"8951c6c53fdbf06bd999541965c86da70a7999ca", "commit_rev":
"f9c093e54e11cb41c6f3402997a97be16568865f"}

[commit-bot: I haz the power, 2017-03-22 21:14:15]

Description was changed from

==========
[Closure Externs] Handle optional params sent to an API callback

An API might conditionally send a response parameter to a caller.
e.g., envision an API:
doStuff({includeResult: true})
which responds with a Result iff includeResult was present and true.

Currently, closure extern generation doesn't handle this case well,
and for a callback like:

callback FooCallback = void(optional FooResponse response);
static void doStuff(DoStuffParams params, FooCallback callback);

generates:

/**
 * @param {DoStuffParams} params
 * @param {function(!FooResponse):void} callback
 */

But this is incorrect, since it indicates that the response would
never be null.

Properly handle these optional responses, and update the test.

BUG=704242
==========

to

==========
[Closure Externs] Handle optional params sent to an API callback

An API might conditionally send a response parameter to a caller.
e.g., envision an API:
doStuff({includeResult: true})
which responds with a Result iff includeResult was present and true.

Currently, closure extern generation doesn't handle this case well,
and for a callback like:

callback FooCallback = void(optional FooResponse response);
static void doStuff(DoStuffParams params, FooCallback callback);

generates:

/**
 * @param {DoStuffParams} params
 * @param {function(!FooResponse):void} callback
 */

But this is incorrect, since it indicates that the response would
never be null.

Properly handle these optional responses, and update the test.

BUG=704242

Review-Url: https://codereview.chromium.org/2766363002
Cr-Commit-Position: refs/heads/master@{#458876}
Committed:
https://chromium.googlesource.com/chromium/src/+/f9c093e54e11cb41c6f3402997a9...
==========

[commit-bot: I haz the power, 2017-03-22 21:14:16]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/f9c093e54e11cb41c6f3402997a9...