Merge pull request #5 from Dwolla/scalafix

Scalafix rule for adding necessary implicits to generated code

README.md

@@ -36,6 +36,8 @@ object FooService {
 }
 ```
 
+These implicit instances can be automatically added to the code generated by Scrooge by running the `AddCatsTaglessInstances` scalafix rule! See below for more detail.
+
 Now you can safely convert your `Future`-based implementation into one in `F[_] : Async`:
 
 ```scala
@@ -64,10 +66,8 @@ trait FooScroogeService[F[_]] {
 }
 
 object FooScroogeService {
-  // these implicits won't be generated by scrooge—but we're working on that!
-  // for now you'll have to add them yourself, either here or somewhere in the 
-  // implicit scope available to the calls shown below under "Finagle Clients" 
-  // and "Finagle Servers"
+  // Let Scalafix generate these instances for you! 
+  // Follow the instructions in the `Scalafix Rule` section below.
   implicit def FooScroogeServiceReaderT[F[_]]: FooScroogeService[ReaderT[F, FooScroogeService[F], *]] =
     Derive.readerT[FooScroogeService, F]
   implicit val FooScroogeServiceFunctorK: FunctorK[FooScroogeService] = Derive.functorK[FooScroogeService]
@@ -100,6 +100,43 @@ val fooImpl: FooScroogeService[IO] = new FooScroogeService[IO] {
 val thriftServer: IO[Nothing] = ThriftServer("address", fooImpl)
 ```
 
+## Scalafix Rule
+
+Add Scalafix to your project's build by [following the instructions](https://scalacenter.github.io/scalafix/docs/users/installation.html#sbt):
+
+1. Add the Scalafix plugin to the project by adding this to `project/plugins.sbt`:
+    ```scala
+    addSbtPlugin("ch.epfl.scala" % "sbt-scalafix" % "0.9.31")
+    ```
+
+2. Enable SemanticDB by adding this to `build.sbt`:
+    ```scala
+    ThisBuild / semanticdbEnabled := true
+    ThisBuild / semanticdbVersion := scalafixSemanticdb.revision
+    ThisBuild / scalafixScalaBinaryVersion := CrossVersion.binaryScalaVersion(scalaVersion.value)
+    ThisBuild / scalafixDependencies += "com.dwolla" %% "finagle-tagless-scalafix" % "0.0.4"
+    ```
+
+3. Run the Scalafix rule automatically after generating the Thrift sources by adding this to `build.sbt`:
+    ```scala
+    Compile / scalafix / unmanagedSources := (Compile / sources).value
+    Compile / compile := Def.taskDyn {
+      val compileOutput = (Compile / compile).value
+
+      Def.task {
+        (Compile / scalafix).toTask(" AddCatsTaglessInstances").value
+        compileOutput
+      }
+    }.value
+    libraryDependencies ++= {
+      val catsTaglessV = "0.14.0"
+      Seq(
+        "org.typelevel" %% "cats-tagless-core" % catsTaglessV,
+        "org.typelevel" %% "cats-tagless-macros" % catsTaglessV,
+      )
+    }
+    ```
+
 ## Artifacts
 
 The Group ID for each artifact is `"com.dwolla"`. All artifacts are published to Maven Central.
@@ -153,6 +190,14 @@ The Group ID for each artifact is `"com.dwolla"`. All artifacts are published to
 <td align="center">Cats Effect 3</td>
 </tr>
 <tr>
+<td><code>"finagle-tagless-scalafix"</code></td>
+<td>Automatically adds implicit instances needed by `asyncMapK` to the companion objects of Finagle services generated by Scrooge</td>
+<td align="center">All</td>
+<td align="center"><g-emoji class="g-emoji" alias="white_check_mark" fallback-src="https://github.githubassets.com/images/icons/emoji/unicode/2705.png">✅</g-emoji></td>
+<td align="center"><g-emoji class="g-emoji" alias="white_check_mark" fallback-src="https://github.githubassets.com/images/icons/emoji/unicode/2705.png">✅</g-emoji></td>
+<td align="center">N/A</td>
+</tr>
+<tr>
 <td><code>"async-utils-twitter-19-4-ce2"</code></td>
 <td rowspan="2">Implementation for Twitter <code>Future</code><br>(with <code>"com.twitter" %% "util-core" % "19.4.0"</code>)</td>
 <td align="center">Cats Effect 2</td>

build.sbt

@@ -16,21 +16,20 @@ inThisBuild(List(
   startYear := Option(2021),
 ))
 
-lazy val CatsEffect2V = "2.5.1"
-lazy val CatsEffect3V = "3.1.1"
-lazy val TwitterUtilsLatestV = "21.5.0"
+lazy val CatsEffect2V = "2.5.4"
+lazy val CatsEffect3V = "3.2.9"
+lazy val TwitterUtilsLatestV = "21.8.0"
 lazy val TwitterUtils19_4V = "19.4.0"
 lazy val CatsTaglessV = "0.14.0"
+lazy val libthriftV = "0.10.0"
 
 lazy val SCALA_2_13 = "2.13.6"
-lazy val SCALA_2_12 = "2.12.14"
-lazy val SCALA_3 = "3.0.0"
+lazy val SCALA_2_12 = "2.12.15"
 
 lazy val Scala2Versions = Seq(SCALA_2_13, SCALA_2_12)
-lazy val Scala2And3 = Seq(SCALA_2_13, SCALA_2_12, SCALA_3)
 
 lazy val scala2CompilerPlugins: Seq[ModuleID] = Seq(
-  compilerPlugin("org.typelevel" % "kind-projector" % "0.13.0" cross CrossVersion.full)
+  compilerPlugin("org.typelevel" % "kind-projector" % "0.13.2" cross CrossVersion.full)
 )
 
 def dedupKindProjectorOptions(opts: Seq[String]): Seq[String] =
@@ -246,21 +245,80 @@ lazy val examples = (projectMatrix in file("examples"))
   .settings(
     libraryDependencies ++= {
       Seq(
-        "org.typelevel" %% "cats-tagless-macros" % "0.14.0",
+        "org.typelevel" %% "cats-tagless-macros" % CatsTaglessV,
       ) ++ (if (scalaVersion.value.startsWith("2")) scala2CompilerPlugins else Nil)
     },
     publish / skip := true,
   )
   .jvmPlatform(scalaVersions = Scala2Versions)
   .dependsOn(`async-utils`)
 
+lazy val `scalafix-rules` = (projectMatrix in file("scalafix/rules"))
+  .jvmPlatform(scalaVersions = Scala2Versions)
+  .settings(
+    moduleName := "finagle-tagless-scalafix",
+    libraryDependencies ++= Seq(
+      "ch.epfl.scala" %% "scalafix-core" % _root_.scalafix.sbt.BuildInfo.scalafixVersion,
+
+    ),
+    scalacOptions ~= { _.filterNot(_ == "-Xfatal-warnings") },
+  )
+
+lazy val `scalafix-input` = (project in file("scalafix/input"))
+  .settings(
+    publish / skip := true,
+    scalaVersion := Scala2Versions.head,
+    libraryDependencies ++= Seq(
+      "com.twitter" %% "scrooge-core" % TwitterUtilsLatestV,
+      "com.twitter" %% "finagle-thrift" % TwitterUtilsLatestV,
+      "org.apache.thrift" % "libthrift" % libthriftV,
+    ),
+    scalacOptions += "-nowarn",
+    scalacOptions ~= { _.filterNot(_ == "-Xfatal-warnings") },
+    semanticdbEnabled := true,
+    semanticdbVersion := scalafixSemanticdb.revision,
+  )
+  .disablePlugins(ScalafixPlugin)
+
+lazy val `scalafix-output` = (project in file("scalafix/output"))
+  .settings(
+    publish / skip := true,
+    scalaVersion := Scala2Versions.head,
+    libraryDependencies ++= Seq(
+      "com.twitter" %% "scrooge-core" % TwitterUtilsLatestV,
+      "com.twitter" %% "finagle-thrift" % TwitterUtilsLatestV,
+      "org.apache.thrift" % "libthrift" % libthriftV,
+      "org.typelevel" %% "cats-tagless-core" % CatsTaglessV,
+      "org.typelevel" %% "cats-tagless-macros" % CatsTaglessV,
+    ),
+    scalacOptions += "-nowarn",
+    scalacOptions ~= { _.filterNot(_ == "-Xfatal-warnings") },
+  )
+  .disablePlugins(ScalafixPlugin)
+
+lazy val `scalafix-tests` = (projectMatrix in file("scalafix/tests"))
+  .jvmPlatform(scalaVersions = Scala2Versions)
+  .settings(
+    publish / skip := true,
+    libraryDependencies += "ch.epfl.scala" % "scalafix-testkit" % _root_.scalafix.sbt.BuildInfo.scalafixVersion % Test cross CrossVersion.full,
+    scalafixTestkitOutputSourceDirectories := (`scalafix-output` / Compile / unmanagedSourceDirectories).value,
+    scalafixTestkitInputSourceDirectories := (`scalafix-input` / Compile / unmanagedSourceDirectories).value,
+    scalafixTestkitInputClasspath := (`scalafix-input` / Compile / fullClasspath).value,
+    scalafixTestkitInputScalacOptions := (`scalafix-input` / Compile / scalacOptions).value,
+    scalafixTestkitInputScalaVersion := (`scalafix-input` / Compile / scalaVersion).value,
+  )
+  .dependsOn(`scalafix-rules`)
+  .enablePlugins(ScalafixTestkitPlugin)
+
 lazy val `async-utils-root` = (project in file("."))
   .aggregate(
     Seq(
       `async-utils-core`,
       `async-utils`,
       `async-utils-twitter`,
       `async-utils-finagle`,
+      `scalafix-rules`,
+      `scalafix-tests`,
       examples,
     ).flatMap(_.projectRefs): _*
   )

project/build.properties

@@ -1 +1 @@
-sbt.version=1.5.3
+sbt.version=1.5.5

project/plugins.sbt

@@ -1,4 +1,5 @@
 addSbtPlugin("io.github.davidgregory084" % "sbt-tpolecat" % "0.1.20")
-addSbtPlugin("com.geirsson" % "sbt-ci-release" % "1.5.7")
+addSbtPlugin("com.github.sbt" % "sbt-ci-release" % "1.5.9")
 addSbtPlugin("com.eed3si9n" % "sbt-projectmatrix" % "0.8.0")
-addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.5.1")
+addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.7.0")
+addSbtPlugin("ch.epfl.scala" % "sbt-scalafix" % "0.9.31")

scalafix/README.md

@@ -0,0 +1,30 @@
+# Scalafix Notes
+
+## Scrooge Updates
+
+Scrooge updates roughly monthly, and occasionally the updates introduce 
+breaking changes in the generated code. (For example, between the `21.5.0` 
+and `21.8.0` versions, [a new abstract method was added to the `ValidatingThriftStructCodec3`](https://github.com/twitter/scrooge/commit/fdb8f8f2d9cc30d6ca06b117fe7a82003f330ba8#diff-1fb7ff7b4c7a64ec907dfa620403b5b190f9829f3d5e6e0d57d07685dd53411f)
+trait, which implementations generated by the older version will be missing.)
+
+As a result, the files in `scalafix/input/src/main/scala/example/thrift` and
+`scalafix/output/src/main/scala/example/thrift` may need to be regenerated when
+the Scrooge version is updated by running the `regenerate-inputs.sh` script with
+the new Scrooge version as the first parameter.
+
+```bash
+./regenerate-inputs.sh 21.8.0
+```
+
+Then edit `scalafix/output/src/main/scala/example/thrift/SimpleService.scala` and replace the
+blank line at the end of the `SimpleService` object with these lines:
+
+```scala
+
+  implicit def SimpleServiceInReaderT[F[_]]: SimpleService[({type Λ[β0] = _root_.cats.data.ReaderT[F, SimpleService[F], β0]})#Λ] =
+    _root_.cats.tagless.Derive.readerT[SimpleService, F]
+
+  implicit val SimpleServiceFunctorK: _root_.cats.tagless.FunctorK[SimpleService] = _root_.cats.tagless.Derive.functorK[SimpleService]
+```
+
+(Newlines and whitespace matter to the tests!)