Investigate re-entrant Properties

[samreid]

In phetsims/axon#179 we identified Property instances that are re-entrant. In this context, re-entrant means a change in value of the Property causes (via listeners) another change in the value of the same Property instance.

Re-entry can occur for at least 3 different reasons, which are document here: phetsims/axon#179 (comment)

value=0.9999999999999998, oldValue=1 // epsilon problem
value=-0.4277580409572783, oldValue=-0.5 // large delta problem
value=[Object], oldValue=[Object] // object changed to object problem.  May be same object?

This issue is to search through the Properties with reentrant: true and:

(a) confirm that the Property really requires reentrant: true
(b) identify the reason for the reentry (may be one of the 3 classes above)
(c-i) see if the code can be rewritten so it no longer requires a reentrant Property, or document why the code uses a re-entrant Property
or
(c-ii) document why the code uses a re-entrant Property

Initially assigning to the responsible-dev for this repo, though it is unclear what the priority should be for this issue.

[samreid]

You can reproduce this problem by temporarily changing reentrant to false, then dragging the leg and pressing reset. The stack trace goes through a DynamicProperty, which I traced to AppendageNode. If you make that DynamicProperty bidirectional: false then the re-entry problem goes away.

[samreid]

I also noticed there is a comment about this in the DynamicProperty:

// only update angle if we are not mouse dragging to avoid reentrance

@jessegreenberg can you please look into this issue?

[jessegreenberg]

A related issue recently came up in #330. I am unable to reproduce the reentrance on master when I remove reentrant from angleProperty and the relevant lines in inverseMap of DynamicProperty. I can however reproduce the issue when I checkout SHAS from around the date of this issue. So this may have been fixed by other commits in this repo, Ill investigate.

[jessegreenberg]

I think I found it, there was an issue with AccessibleSlider identified in phetsims/gravity-force-lab-basics#72 and the general fix made it so that this is no longer reentrant. I will remove reentrant: true and other references here and test to make sure reentrance is no more while everything still works.

[jessegreenberg]

reentrant: true removed and sim is passing fuzz tests and a11y features are working. I can't reproduce the problem when going through steps in #298 (comment). Lines and documentation in #298 (comment) were removed. Closing.