[Bug] Stat Stages are now changed individually instead of all at once

[PrabbyDD]

What are the changes the user will see?

Defiant and Competitive will now properly interact with moves that modify multiple stats stages.

Why am I making these changes?

Fixes #4281

What are the changes from a developer perspective?

If multiple stats are being changed in StatStageChangePhase, a new SSCPhase is created for each individual stat and then the current SSCPhase is ended.

Screenshots/Videos

defiant.fix.mp4

How to test the changes?

Override file, or the test file made

Checklist

• I'm using beta as my base branch
• There is no overlap with another PR?
• The PR is self-contained and cannot be split into smaller PRs?
• Have I provided a clear explanation of the changes?
• Have I considered writing automated tests for the issue?
• [ ] If I have text, did I make it translatable and add a key in the English locale file(s)?
• Have I tested the changes (manually)?
  • Are all unit tests still passing? (npm run test)
• Are the changes visual?
  • Have I provided screenshots/videos of the changes?

[DayKev]

It seems like the reason this bug exists is because we combine stat changes into a single SSCPhase which is different from mainline where each stat change is handled individually. It speeds things up but apparently also causes bugs. It might be better to instead have the SSCPhase check if it's changing multiple stats at once, and to unshift a new SSCPhase for each stat and end the current SSCPhase after doing so.

[PrabbyDD]

It seems like the reason this bug exists is because we combine stat changes into a single SSCPhase which is different from mainline where each stat change is handled individually. It speeds things up but apparently also causes bugs. It might be better to instead have the SSCPhase check if it's changing multiple stats at once, and to unshift a new SSCPhase for each stat and end the current SSCPhase after doing so.

This is what I was thinking originally but I wasnt sure where to start when trying to implement this - I figured the solution I committed would be simpler and easier to understand. Where do I start when trying to add multiple SSCPhases? Also should I be hard coding it in for specifically defiant and competitive?

[torranx]

I'd like to see Defiant test cases as well

[DayKev]

It seems like the reason this bug exists is because we combine stat changes into a single SSCPhase which is different from mainline where each stat change is handled individually. It speeds things up but apparently also causes bugs. It might be better to instead have the SSCPhase check if it's changing multiple stats at once, and to unshift a new SSCPhase for each stat and end the current SSCPhase after doing so.

This is what I was thinking originally but I wasnt sure where to start when trying to implement this - I figured the solution I committed would be simpler and easier to understand. Where do I start when trying to add multiple SSCPhases? Also should I be hard coding it in for specifically defiant and competitive?

At the beginning of the SSCPhase's start() function, check if more than one different stat is being changed, and if so make a loop that passes each stat (plus the other constructor fields) to a new SSCPhase via unshiftPhase(new SSCPhase(...)). Then after the loop completes (if it was run) the current SSCPhase is ended via return this.end();. Something like this (more might be necessary, haven't tested this):

  start() {
    if (this.stats.length > 1) {
      for (let i = 0; i < this.stats.length; i++) {
        const stat = [this.stats[i]];
        this.scene.unshiftPhase(new StatStageChangePhase(this.scene, this.battlerIndex, this.selfTarget, stat, this.stages, this.showMessage, this.ignoreAbilities, this.canBeCopied, this.onChange));
      }
      return this.end();
    }

[DayKev]

Updated the OP with the changes.