Textarea: hang when Viewport resize event soon after startup

[bill]

If there's a viewport resize event soon after page load, it can cause an endless loop in the Textarea resize code. Calling Textarea.resize() triggers a Textarea.onresize event, which calls Textarea.resize() again and so forth.

Apply attached patch to Viewport.js and then run dijit/tests/form/test_Textarea.html on IE8. See the CPU peg at 100% and the page get stuck while downloading images for the test.

[bill]

make Viewport start monitoring viewport size earlier than before, which triggers a "spurious" viewport resize event when a scrollbar appears

[bill]

In [29507]:

For dojo core and dijit, use require(dojo/domReady!?, cb) rather than ready(cb) so that dojo code can run against other dojo loaders.

Exceptions:

• robot.initRobot() related code that checks when page inside of iframe has finished initializing
• dijit-legacy-requires back-compat code for synchronous mode, which load modules that weren't explicitly required (ex: how dijit/_WidgetBase loads dojo/_base/manager)
• dojo/parser's parseOnLoad: true support
• dojo-config-require sync mode operation

This change depends on dojo/domReady! executing it's callbacks in the order they were registered. To ensure that client-defined callback code executes after the callbacks inside of dojo/dijit, client code should either continue using dojo/ready, or use a nested require(dojo/domReady!?, ...) inside of the original require that loads the modules:

require([...], function(...){
         require(["dojo/domReady!"], ...)
}

Further, when the client code needs to run the parser and then run another block of code, it should be done like:

require([..., "dojo/parser"], function(..., parser){
     parser.parse().then(...);
}

Viewport.js needed a setTimeout() to workaround bug #15866. It should probably be removed when that bug is fixed.

Refs #15616, #15866 !strict. Changes on trunk/.

[doughays]

fix to review

[doughays]

bill, I attached a patch that I was hoping you could test out. The textarea native onresize event should not have been connected to in addition to Viewport.on/resize

[bill]

Yup, that definitely fixes the problem, thanks!

[doughays]

In [29530]:

Fixes #15864, #15866. Remove textarea.onresize event trap since the Viewport.on/resize handles this effectively to avoid a resize loop.

[doughays]

In [29956]:

Fixes #16334. Refs #15866, #15864. Remove onscroll event handler to avoid resize event loop.