Rutherford Scattering code-review checklist

[schmitzware]

PhET code-review checklist

Build and Run Checks

• Does the sim pass lint?
• Does the sim build without errors?
• Does the sim start up? (requirejs and built versions)
• Does the sim experience any assertion failures? (run with query parameter 'ea')
• Does the sim pass a scenery fuzzer test? (run with query parameter 'fuzzMouse')

Strings

• Are there any unused strings? (Strings that appear in the JSON file but are unused in the simulation should be removed).
• Are there any strings that are not being internationalized? (run with query parameter 'stringTest=x', you should see nothing but 'x' strings)
• Does the sim layout gracefully handle internationalized strings that are twice as long as the English strings? (run with query parameter 'stringTest=double')
• Does the sim layout gracefully handle internationalized strings that are exceptionally long? (run with query parameter 'stringTest=long')
• Does the sim stay on the sim page (doesn't redirect to an external page) when running with the query parameter 'stringTest=xss'. Only test on one desktop platform.
• Does the sim layout gracefully handle internationalized strings that are shorter than the English strings? (run with query parameter 'stringTest=X')
• Make sure the string keys are all perfect, they are difficult to change after 1.0.0 published.

Repository structure

• Are all required files and directories present?

  For a sim repository named “my-repo”, the general structure should look like this (where assets/, audio/ or images/ may be omitted if the sim doesn’t have those types of assets).

   my-repo/
      assets/
      audio/
         license.json
      doc/
         model.md
         implementation-notes.md
      images/
         license.json
      js/
         my-repo-config.js
         my-repo-main.js
      .gitignore
      my-repo_en.html
      my-repo-strings_en.json
      Gruntfile.js
      LICENSE
      package.json
      README.md

For a common-code repository, the structure is similar, but some of the files and directories may not be present if the repo doesn’t have audio, images, strings, or a demo application.

• Is the js/ directory properly structured?

  All JavaScript source should be in the js/ directory. There should be a subdirectory for each screen (this also applies for single-screen sims). For a multi-screen sim, code shared by 2 or more screens should be in a js/common/ subdirectory. Model and view code should be in model/ and view/ subdirectories for each screen and common/. For example, for a sim with screens “Introduction” and “Custom”, the general directory structure should look like this:

   my-repo/
      js/
         common/
            model/
            view/
         custom
            model/
            view/
         introduction
            model/
            view/
         my-repo-config.js
         my-repo-main.js

• Is there a file in assets/ for every file in audio/ and images/?
• Are all license.json files populated? audio/license.json and images/license.json should enumerate all files in those directories. For the format of license.json files, go here.
• Does the README.md format and content match PhET guidelines? Was it generated by grunt generate-published-README or grunt generate-unpublished-README?
• Does Gruntfile.js point to chipper/js/grunt/Gruntfile.js?
• Are dependencies in package.json the same as js/*-config.js? Do they match what is actually used by the sim? (ie, no missing dependencies, no unused dependencies)
• Is the LICENSE file correct? (Generally GPL v3 for sims, MIT for common code, but there are exceptions to this.)
• Does .gitignore match other repositories?
• Does *-main.js follow PhET conventions? Does it contain correct credits (options.credits passed to Sim constructor)?
• Are there git repository branches that are no longer used and should be pruned?

Coding conventions

• Does the code style meet PhET's code-style guidelines, as described in the “Coding Style Guidelines” section of "PhET Development Overview"?
• Is the code formatted according to PhET conventions? See phet-idea-code-style.xml for IntelliJ IDEA code style.

Documentation

• Are documentation conventions followed, as described in the “Coding Style Guidelines” section of the PhET Development Overview?
• Does model.md adequately describe the model, in terms appropriate for teachers?
• Does implementation-notes.md adequately describe the implementation, with an overview that will be useful to future maintainers?
• Are sim-specific query parameters (if any) identified and documented in one location?

Common Errors

• Is Math.round used where dot.Util.roundSymmetric should be used? Math.round does not treat positive and negative numbers symmetrically, see fix nearest-neighbor rounding in Util.toFixed dot#35 (comment)
• Is toFixed used where dot.Util.toFixed or dot.Util.toFixedNumber should be used? JavaScript's toFixed is notoriously buggy, behavior differs depending on browser, because the spec doesn't specify whether to round or floor.
• User interface components with enabled:false should also have pickable:false
• Are random numbers using DOT/Random or seedable sources?

Organization, Readability, Maintainability

• Does the organization and structure of the code make sense? Do the model and view contain types that you would expect (or guess!) by looking at the sim? Do the names of things correspond to the names that you see in the user interface?
• Are appropriate design patterns used?
• Is inheritance used where appropriate? Does the type hierarchy make sense?
• Is there any unnecessary coupling? (e.g., by passing large objects to constructors, or exposing unnecessary properties/functions)
• Is there too much unnecessary decoupling? (e.g. by passing all of the properties of an object independently instead of passing the object itself)?
• Are the source files reasonable in size? Scrutinize large files with too many responsibilities - can responsibilities be broken into smaller delegates?
• Are any significant chunks of code duplicated? This will be checked manually as well as with https://github.com/danielstjules/jsinspect
• Is there anything that should be generalized and migrated to common code?
• Are there any TODO or FIXME comments in the code? They should be addressed or promoted to GitHub issues.

Performance, Usability

• Does the sim perform as desired across the range of supported platforms? (eg, not too slow on slow platforms, not too fast on fast platforms)
• If the sim uses WebGL, does it have a fallback? Does the fallback perform reasonably well? (run with query parameter 'webgl=false')
• Are UI components sufficiently responsive? (especially continuous UI components, such as sliders)
• Are pointer areas optimized, especially for touch? (run with query parameter 'showPointerAreas')
• Do pointer areas overlap? (run with query parameter 'showPointerAreas')
• Is DT capped appropriately? Try switching applications or browser tabs, then switch back. Did the model take one big/long/awkward step forward? If so, dt may need to be capped.

Memory Leaks

• Does a heap comparison using Chrome Developer Tools indicate a memory leak? (Describing this process is beyond the scope of this document.)
• For each common-code component (sun, scenery-phet, vegas, …) that opaquely registers observers or listeners, is there a call to that component’s dispose function, or documentation about why dispose is unnecessary?
• Are there leaks due to registering observers or listeners? These guidelines should be followed, or documentation added about why following them is not necessary:
  • AXON: Property.link is accompanied by Property.unlink.
  • AXON: PropertySet.link is accompanied by PropertySet.unlink.
  • AXON: Creation of DerivedProperty is accompanied by detach.
  • AXON: Creation of Multilink is accompanied by detach.
  • AXON: Events.on is accompanied by Events.off.
  • AXON: Emitter.addListener is accompanied by Emitter.removeListener.
  • SCENERY: Node.addEventListener is accompanied by Node.removeEventListener
  • SCENERY: Node.on is accompanied by Node.off
  • TANDEM: tandem.addInstance is accompanied by tandem.removeInstance.
• Do all types that require a dispose function have one?

[pixelzoom]

Put on my plate at 3/3/16 dev meeting. @schmitzware assign to me when ready for review.

[schmitzware]

I just need get IntellJ setup with the formatting bits so I can run it through there. Should be ready after that.

[schmitzware]

So, just so you know - I broke up the Rutherford/Atom screens a bit more but not overly so. I ended up consolidating the gun, target & dashed zoomed line in to it's own node and re-layed out things. I didn't see the need to abstract out further seeing that it's ~125 lines of code, mainly layout, and it looks like things will change (space, legend, etc.) with the addition of that new bits in the design document. If you feel strongly the other way, just say so, it's no problem.

[pixelzoom]

Code review complete, see above for issue (or look for 'dev:code-review' tag). Overall this sim is in great shape, nice job.

@schmitzware said that he had checked for memory leaks (heap comparison), so I've skipped that step, since it would take me some time.

The only issue that I've assigned to myself is #49. I'd like to take a closer look at duplication in ScreenView subtypes.

@schmitzware, Let me know if you have any questions, feel free to "push back" on anything you think is unnecessary. And feel free to proceed with addressing issues, I won't be making any further changes to code without consulting you first.

[pixelzoom]

Btw... The only issues where I made commits are #39, #43, #47.

[schmitzware]

Just waiting on updated images/assets files at this point.

[schmitzware]

Images/Assets have all been updated - checklist looks complete - what's the next step here?

[ariel-phet]

@schmitzware next step would be to publish a "dev" version and have our testers bang on it for a bit to see if there are any bugs.

[pixelzoom]

Next step is for me to note that all code-review issues have been addressed, and close this issue.

[pixelzoom]

To clarify what @ariel-phet said in #30 (comment)...

A "dev test" is an informal test of a "dev" (development) version. It's less rigorous than an "RC" (release candidate) test, in that it doesn't have a format test matrix, etc. The goal is to find any bugs that may be lurking with a minimal investment of tester and developer resources.

The steps are:

(1) Publish dev version 1.0.0.-dev.1. Ask me how, or see https://github.com/phetsims/phet-info/blob/master/sim_deployment.md. Requires that you have an account and permissions on spot.colorado.edu (the dev server).

(2) Create an issue in tasks with title "Dev test Rutherford Scattering 1.0.0-dev.1", assign it to @ariel-phet. See phetsims/tasks#488 for a similar issue.

(3) Evaluate and (likely) fix any issues that testers find. Possibly go to step (1) and do another cycle through the process.

When a sim has passed dev testing, the next phase is typically RC testing, followed by publication. Since this sim isn't going to be published until feature #20 is added, I don't know if RC testing is going to occur right away.

[ariel-phet]

We will actually RC test this sim for one round, even before #20 is added.