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Enhancement: unused public methods

Open RichardBradley opened this issue 10 years ago • 5 comments

For standalone projects (i.e. not libraries), unused public methods are a nuisance that can be hard to track down.

Possibly scapegoat could detect these and warn?

The difficulty with this inspection is that it is completely inapplicable to many projects (i.e. those intended as libraries).

RichardBradley avatar Aug 14 '14 17:08 RichardBradley

I am introducing opt in inspections so that's not an issue (that libraries don't want it as it can be opt in) On 14 Aug 2014 18:01, "Richard Bradley" [email protected] wrote:

For standalone projects (i.e. not libraries), unused public methods are a nuisance that can be hard to track down.

Possibly scapegoat could detect these and warn?

The difficulty with this inspection is that it is completely inapplicable to many projects (i.e. those intended as libraries).

— Reply to this email directly or view it on GitHub https://github.com/sksamuel/scalac-scapegoat-plugin/issues/41.

sksamuel avatar Aug 14 '14 17:08 sksamuel

Lol, weird sksamuel and I were talking about deeper code inspections like this one.

I guess this one is easy for public methods. You would want a clear documentation for switching it on/off in the config (possibly in the message itself).

On 14 Aug 2014, at 18:01, Richard Bradley [email protected] wrote:

For standalone projects (i.e. not libraries), unused public methods are a nuisance that can be hard to track down.

Possibly scapegoat could detect these and warn?

The difficulty with this inspection is that it is completely inapplicable to many projects (i.e. those intended as libraries).

— Reply to this email directly or view it on GitHub.

rorygraves avatar Aug 14 '14 17:08 rorygraves

I think one of the challenges with this inspection is the interesting cases rapidly devolve into graph walking the entire code. E.g. a method overrides a trait. To determine if the method is dead you need to find all instances of calls to the trait (only if somebody ever creates an instance). I think good dead code detection is going to take some interesting deep code analysis. This is something I'm really interested in and am hoping to use the core of the Ensime project to do it.

rorygraves avatar Aug 14 '14 17:08 rorygraves

I think it would be reasonably straightforward but a bit of trail of error to do this:

For every method declaration add it to a list of declared methods For every method invocation add it to a list of invoked methods

After walking the entire graph, declarations - invocations are unused. This doesn't account for traits or superclasses which might need a bit more work.

On 14 August 2014 18:30, Rory [email protected] wrote:

I think one of the challenges with this inspection is the interesting cases rapidly devolve into graph walking the entire code. E.g. a method overrides a trait. To determine if the method is dead you need to find all instances of calls to the trait (only if somebody ever creates an instance). I think good dead code detection is going to take some interesting deep code analysis. This is something I'm really interested in and am hoping to use the core of the Ensime project to do it.

— Reply to this email directly or view it on GitHub https://github.com/sksamuel/scalac-scapegoat-plugin/issues/41#issuecomment-52214948 .

sksamuel avatar Aug 14 '14 18:08 sksamuel

Its definitely worth a try. I would love to see this working and would be a cool win for scapegoat.

rorygraves avatar Aug 14 '14 19:08 rorygraves