Incorrect RegExp in export-name rule leads to superfluously permissive

[IllusionMH]

As was discovered in #623 (comment) RegExp in export-name rule has issue with improperly escaped . as well as missing check for line start/end. These problems leads to several problems.

For class name SomeClass it allows:

1. Wrong . escape: SomeClassButAnyTextHere.tsx, SomeClassWithoutExtension
2. No end of line check: SomeClass.ts.or.not
3. No start of line check: LooksLikeSomeClass.ts
4. Everything combined NotSureThatSomeClassIsSomewhereInThis.long.filename

According to description I would expect only SomeClass.ts or at least SomeClass.suffix.tsx (but better to make it as option).

Existing test with a problem ExportNameRulePassingTestInput2.tsx ends on 2.tsx but class name doesn't have 2 et the end.

What do you think about cases above and which should be disallowed by this rule?

[JoshuaKGoldberg]

Agreed, this is an existing bug that should be fixed as suggested; the author likely meant to escape the . properly.

[IllusionMH]

What about cases 2 and 3?

[JoshuaKGoldberg]

2. No end of line check: SomeClass.ts.or.not

When would this case be typically hit? SomeClass.spec.tsSomeClass.stub.ts, perhaps? My understanding of the RegExp's intent is that it was meant to allow (name of the exported thing) plus (any extension). It makes sense that we would consider .spec.ts to be the extension. Although the technical file extension is anything after the last ., this rule's logic would be anything after the first ..

3. No start of line check: LooksLikeSomeClass.ts

Yes, this looks like a bug.

Edit: yes, .stub.ts would be more realistic

[IllusionMH]

Not sure that .spec.ts files should export class, but may be useful for something like .stub.ts.
If required, strict check for "extension part" might be added as option after feedback.

Will fix 1 and 3.

[IllusionMH]

Actually with fixed check for start of the line there are 80 (why not 93?) errors because of export class Rule ... in this repo 🤣
Does in make sense to add this fix to 6.0? Might be breaking for someone.
Implementation and tests almost finished.