New Rule: ImplicitClassPrivateParams (fix #542) #553

LeonardMeyer · 2018-01-13T15:41:29Z

No description provided.

olafurpg

Thank you for this contribution! I apologize the slow responses, last week has been busy. I'm glad to see you got the tests running on Windows. A few comments

olafurpg · 2018-01-15T14:31:54Z

scalafix-core/shared/src/main/scala/scalafix/internal/rule/ImplicitClassPrivateParams.scala

+import scalafix.{Patch, Rule}
+
+case object ImplicitClassPrivateParams
+    extends Rule("ImplicitClassPrivateParams") {


ImplicitClassPrivateVal

olafurpg · 2018-01-15T14:46:23Z

scalafix-core/shared/src/main/scala/scalafix/internal/rule/ImplicitClassPrivateParams.scala

+
+  override def fix(ctx: RuleCtx): Patch = {
+    ctx.tree.collect {
+      case Defn.Class(mods, _, _, primCtor, _) if hasImplicitMod(mods) =>


I think we can refine the condition to only apply for AnyVals that are missing private

t.collect { case Defn.Class( cmods, _, _, Ctor.Primary(_, _, (Term.Param(pmods, _, _, _) :: Nil) :: Nil), Template(_, init"AnyVal" :: Nil, _, _) ) => for { _ <- cmods.find(_.is[Mod.Implicit]) if !pmods.exists(_.is[Mod.Private]) valmod <- pmods.find(_.is[Mod.ValParam]) } yield ctx.addLeft(valmod, "private ") }

For non-anyvals it's possible to remove the val parameter, implicit class Foo(x: Int) { .. }. Classes that extends AnyVal are however forced to add the val modifier which makes it easy to accidentally forget private

Got it. Can you explain to me how is() is working here ? I noticed it but thought it only worked with tokens. Where are the instances for Classifiable/Classifier ?

The instances are generated by the scalameta @ast macro annotations. It's a flexible mechanism to guard against categories of trees/tokens both via .is[T] or in pattern matching with case T(). You can build custom groups of classes like we do in scalafix https://github.com/scalacenter/scalafix/blob/00199145261b958fb12cf256773c2ed08f336359/scalafix-core/shared/src/main/scala/scalafix/util/TokenClasses.scala

Ok thanks. One last question : your implementation ignores cases where final or protected is present. Don't we care ?

olafurpg · 2018-01-15T14:46:57Z

scalafix-tests/input/src/main/scala/test/ImplicitClassPrivateParams.scala

+    def doubled: String = str + str
+  }
+
+  implicit class XtensionVar(var str: String) {


We can ignore var cases since those are less commonly (if ever) used for implicit classes.

Isn't it best to keep these as non reg tests ? Unless you think this is being overzealous.

Negative tests are good :) I probably don't write enough of them. We don't need too many here however since the implementation guards against val

olafurpg · 2018-01-15T14:48:15Z

scalafix-tests/input/src/main/scala/test/ImplicitClassPrivateParams.scala

+    def doubled: Int = int + int
+  }
+
+  implicit class Xtension(int: Int) {


We can ignore non-AnyVals since those fields are private by default unless they're case classes, but case classes are rarely used for implicit classes.

olafurpg

Nice catch with final val!

olafurpg · 2018-01-17T12:04:55Z

scalafix-core/shared/src/main/scala/scalafix/internal/rule/ImplicitClassPrivateParams.scala

+        val optPatch = for {
+          _ <- cMods.find(_.is[Mod.Implicit])
+          if !pMods.exists(_.is[Mod.Private])
+          valMod <- pMods.find(_.is[Mod.ValParam])


You are correct that this does not handle final val param: T. We can use .find(!_.is[Mod.Annot]) instead, but adding private can still break cases like override val param: T. We should probably exclude cases that contain override.

I think override isn't an issue since we're only looking for implicit value classes and AFAIK they can't extend both AnyVal and a base class. I pushed another commit WDYT ?

AnyVals can inherit from "universal traits"

@ trait Foo extends Any { def bar: Int def plusOne = bar + 1 } defined trait Foo @ implicit class UInt(override val bar: Int) extends AnyVal with Foo defined class UInt @ 2.plusOne res4: Int = 3

See http://docs.scala-lang.org/overviews/core/value-classes.html

@olafurpg Indeed. This case won't be taken into account though, because in your implem you explicitly target a sole Init (AnyVal here).

olafurpg

Just a few minor comments, otherwise I think this rule is good to go 🔥

olafurpg · 2018-01-19T10:59:08Z

scalafix-core/shared/src/main/scala/scalafix/internal/rule/ImplicitClassPrivateVal.scala

+    }.asPatch
+  }
+
+  private def containsPrivateOrProtected(pMods: List[Mod]) =


nitpick, for simple implementations like here I think it's clearer to inline, by adding a method you need to look at it's implementation to know what it does.

olafurpg · 2018-01-19T11:10:26Z

website/src/main/tut/docs/rules/ImplicitClassPrivateVal.md

+
+# ImplicitClassPrivateVal
+
+`val` fields of implicit classes are accessible as an extension. 


Non-private val fields of implicit classes leak as publicly accessible extension methods.

olafurpg · 2018-01-19T11:11:51Z

website/src/main/tut/docs/rules/ImplicitClassPrivateVal.md

+"message".str // does not compile
+```
+
+This rule safely ignores all other modifiers.


Note. This rule only triggers for val fields, it ignores other modifiers such as var.

olafurpg · 2018-01-19T11:13:49Z

scalafix-core/shared/src/main/scala/scalafix/internal/rule/ImplicitClassPrivateVal.scala

+          _,
+          _,
+          Ctor.Primary(_, _, (Term.Param(pMods, _, _, _) :: Nil) :: Nil),
+          Template(_, init"AnyVal" :: Nil, _, _))


we can lift the restriction that it cannot mix in universal classes, if you are feeling more ambitious 😄

I think it's better to wait and see if people actually need that because as you said, the error is more likely to happen with implicit value classes. Speaking of, should I rename the rule to ImplicitValueClassPrivateVal ?

I think it's better to wait and see if people actually need that because as you said, the error is more likely to happen with implicit value classes.

I agree.

Speaking of, should I rename the rule to ImplicitValueClassPrivateVal ?

Good question. How about LeakingImplicitClassVal? That gives us room to later support non-AnyVal in case there's demand. I think it's good to hint in the name what the problem is and the Leaking* prefix is consistent with other upcoming rules like LeakingSealed

LeonardMeyer · 2018-01-22T22:01:12Z

@olafurpg Fixed it

olafurpg

LGTM 👍 Thank you @LeonardMeyer for addressing all of the comments! 💃

LeonardMeyer force-pushed the priv-val-ext-method branch 2 times, most recently from 29505aa to de27239 Compare January 13, 2018 16:12

olafurpg suggested changes Jan 15, 2018

View reviewed changes

LeonardMeyer force-pushed the priv-val-ext-method branch from 3d847bb to e4fe208 Compare January 17, 2018 07:32

olafurpg suggested changes Jan 17, 2018

View reviewed changes

LeonardMeyer force-pushed the priv-val-ext-method branch 3 times, most recently from 2a5e005 to bec3eb8 Compare January 18, 2018 08:27

olafurpg suggested changes Jan 19, 2018

View reviewed changes

olafurpg mentioned this pull request Jan 19, 2018

Add DisableSyntax features (default arguments, etc) and New rule MissingFinal #548

Merged

New LeakingImplicitClassVal rule scalacenter#542

dab04bc

LeonardMeyer force-pushed the priv-val-ext-method branch from bec3eb8 to dab04bc Compare January 19, 2018 23:38

olafurpg approved these changes Jan 23, 2018

View reviewed changes

olafurpg merged commit dc99000 into scalacenter:master Jan 23, 2018

LeonardMeyer deleted the priv-val-ext-method branch January 23, 2018 10:37

MasseGuillaume added this to the v0.5.8 milestone Jan 25, 2018

MasseGuillaume changed the title ~~New ImplicitClassPrivateParams rule #542~~ New Rule: ImplicitClassPrivateParams #542 Jan 25, 2018

MasseGuillaume changed the title ~~New Rule: ImplicitClassPrivateParams #542~~ New Rule: ImplicitClassPrivateParams (fix #542) Jan 25, 2018

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

New Rule: ImplicitClassPrivateParams (fix #542) #553

New Rule: ImplicitClassPrivateParams (fix #542) #553

LeonardMeyer commented Jan 13, 2018 •

edited

Loading

olafurpg left a comment

olafurpg Jan 15, 2018

olafurpg Jan 15, 2018

LeonardMeyer Jan 15, 2018

olafurpg Jan 16, 2018

LeonardMeyer Jan 16, 2018

olafurpg Jan 15, 2018

LeonardMeyer Jan 15, 2018

olafurpg Jan 16, 2018

olafurpg Jan 15, 2018

olafurpg left a comment

olafurpg Jan 17, 2018

LeonardMeyer Jan 17, 2018 •

edited

Loading

olafurpg Jan 17, 2018

LeonardMeyer Jan 17, 2018 •

edited

Loading

olafurpg left a comment

olafurpg Jan 19, 2018

olafurpg Jan 19, 2018

olafurpg Jan 19, 2018

olafurpg Jan 19, 2018

LeonardMeyer Jan 19, 2018 •

edited

Loading

olafurpg Jan 19, 2018

LeonardMeyer commented Jan 22, 2018

olafurpg left a comment


		# ImplicitClassPrivateVal

		`val` fields of implicit classes are accessible as an extension.

New Rule: ImplicitClassPrivateParams (fix #542) #553

New Rule: ImplicitClassPrivateParams (fix #542) #553

Conversation

LeonardMeyer commented Jan 13, 2018 • edited Loading

olafurpg left a comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

olafurpg left a comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

LeonardMeyer Jan 17, 2018 • edited Loading

Choose a reason for hiding this comment

Choose a reason for hiding this comment

LeonardMeyer Jan 17, 2018 • edited Loading

Choose a reason for hiding this comment

olafurpg left a comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

LeonardMeyer Jan 19, 2018 • edited Loading

Choose a reason for hiding this comment

Choose a reason for hiding this comment

LeonardMeyer commented Jan 22, 2018

olafurpg left a comment

Choose a reason for hiding this comment

LeonardMeyer commented Jan 13, 2018 •

edited

Loading

LeonardMeyer Jan 17, 2018 •

edited

Loading

LeonardMeyer Jan 17, 2018 •

edited

Loading

LeonardMeyer Jan 19, 2018 •

edited

Loading