Missing mergers: no-caller, no-eval

[joeyj-msft]

🐛 Bug Report

• tslint-to-eslint-config version: dunno. used npx to run
• ESLint version: 5.16.0
• Node version: 8.16.0

Actual Behavior

my eslint config is not updated

console output
✨ 101 rules replaced with their ESLint equivalents. ✨
📢 4 ESLint rules behave differently from their TSLint counterparts: 📢

• no-invalid-this:
  • Functions in methods will no longer be ignored.
• one-var:
  • Variables declared in for loops will no longer be checked.
• no-plusplus:
  • ++ and -- operators will now only be allowed in for loops.
• class-methods-use-this:
  • allow-protected methods will no longer be ignored.
    💀 2 errors thrown. 💀
    Check ./tslint-to-eslint-config.log for details.
    ️👀 132 rules do not yet have ESLint equivalents; defaulting to eslint-plugin-tslint. 👀
    ✅ All is well! ✅

log file
no-eval threw an error during conversion: Error: No merger for multiple output no-eval rule configurations.
at exports.convertRules (...\npm-cache_npx\14132\node_modules\tslint-to-eslint-config\src\rules\convertRules.js:37:67)
at exports.convertConfig (...\npm-cache_npx\14132\node_modules\tslint-to-eslint-config\src\conversion\convertConfig.js:15:48)
at
at process._tickCallback (internal/process/next_tick.js:189:7)
no-arg threw an error during conversion: Error: No merger for multiple output no-caller rule configurations.
at exports.convertRules (...\npm-cache_npx\14132\node_modules\tslint-to-eslint-config\src\rules\convertRules.js:37:67)
at exports.convertConfig (...\npm-cache_npx\14132\node_modules\tslint-to-eslint-config\src\conversion\convertConfig.js:15:48)
at
at process._tickCallback (internal/process/next_tick.js:189:7)

Expected Behavior

eslint config would be updated

Reproduction

Can you reply to this issue and let me know how much help you need to repro? I'd prefer not to just copy config/details from an internal repo.

[joeyj-msft]

This was actually changing my eslint config and the errors were non-blocking :)

[JoshuaKGoldberg]

Oh hi again @joeyj-msft! I'm going to re-open this issue because it's still a bug I'd like to fix. 😄 thanks for reporting!

Let's assume 0.2.2 as the version.

[JoshuaKGoldberg]

https://github.com/typescript-eslint/tslint-to-eslint-config/blob/master/docs/Architecture.md#rule-mergers describes the root issue here. There are multiple instances of the no-eval and no-callee rules being output, so there needs to be a Merger in code created to handle that.

[joeyj-msft]

@JoshuaKGoldberg I'm wondering if this could generically handle merging the configs: https://lodash.com/docs/4.17.15#merge

[JoshuaKGoldberg]

Ah, I'd rather avoid using merge or other forms of generic object merging. There might be rules -either in the core ruleset or some contributed ones- where merging isn't as clean and simple as that. For now, let's be careful and have unfortunately explicit logic per rule.

[joeyj-msft]

Makes sense. How about an interim approach at outputting the conflicting rules in the log? I'd be happy to take a look at that as the merge will get painful to implement for each case

[JoshuaKGoldberg]

Interesting point. I agree, and that's what it's supposed to be now! 😆 Great observation.

Problem: this is being reported as an error with a full stack. Filed #143 to improve the error UX.

Let's keep this issue, #135, for adding in the missing merger.