Explicitly discard non-unit values in @react macro #630

steinybot · 2023-03-30T02:08:17Z

Fixes #629

It took me a little while to get things setup to reproduce the problem. The key things are Scala 2.13.10 and the -Wnonunit-statement and -Xfatal-warnings scalac options.

I think keeping the sbt-tpolecat plugin is a good idea as that is how I encountered this issue in the first place, however that's your call. I can pull it out into a separate PR if that is preferable.

steinybot · 2023-03-30T02:08:55Z

.sbtopts

I kept getting OOME's in sbt trying to run the tests.

steinybot · 2023-03-30T02:09:30Z

build.sbt

@@ -7,11 +9,14 @@ addCommandAlias(
 )

 val scala212 = "2.12.16"
-val scala213 = "2.13.6"
+val scala213 = "2.13.10"


Scala 2.13.10 identifies more things as unused.

steinybot · 2023-03-30T02:10:13Z

build.sbt

 val scala3   = "3.0.1"

 ThisBuild / scalaVersion := scala213
 ThisBuild / semanticdbEnabled := true
+ThisBuild / semanticdbVersion := "4.7.6"


The default version that sbt 1.7.3 provides is not compiled for Scala 2.13.10 so this needs an update. This can be removed when sbt is updated.

steinybot · 2023-03-30T02:10:45Z

build.sbt

 val scala3   = "3.0.1"

 ThisBuild / scalaVersion := scala213
 ThisBuild / semanticdbEnabled := true
+ThisBuild / semanticdbVersion := "4.7.6"
+
+ThisBuild / tpolecatDefaultOptionsMode := DevMode


This turns off fatal warnings.

steinybot · 2023-03-30T02:11:31Z

build.sbt

-  scalacOptions ++= Seq(
-    "-encoding",
-    "UTF-8",
-    "-feature",
-    "-language:implicitConversions"
-  ) ++ (CrossVersion.partialVersion(scalaVersion.value) match {
+  scalacOptions ++= (CrossVersion.partialVersion(scalaVersion.value) match {
    case Some((3, _)) =>
      Seq(
-        "-unchecked",
        "-source:3.0-migration"
      )
    case _ =>
-      Seq(
-        "-deprecation",
-        "-language:higherKinds",
-        "-Ywarn-unused:imports,privates,locals"
-      )


These are all provided by sbt-tpolecat.

steinybot · 2023-03-30T02:11:44Z

core/src/main/scala-2/slinky/core/annotations/react.scala

This is the fix.

I don't actually know what these statements are for. Could we remove them?

To be completely honest, I don't remember anymore why these are around. I think let's just get the fix in for now and file a separate issue for figuring out if these are actually necessary.

I get the feeling that these may have been to address an "unused type" warning.

steinybot · 2023-03-30T02:12:41Z

tests/build.sbt

@@ -21,3 +23,18 @@ jsDependencies ++= Seq(
  (ProvidedJS / "react-dom/umd/react-dom-server.browser.development.js"
    minified "react-dom/umd/react-dom-server.browser.production.min.js" dependsOn "react-dom/umd/react-dom.development.js" commonJSName "ReactDOMServer") % Test
 )
+
+tpolecatOptionsMode := CiMode


This enables fatal warnings.

steinybot · 2023-03-30T02:14:43Z

tests/build.sbt

+// Unit statements are prevalent in the tests. There is no way to suppress them:
+// See https://github.com/typelevel/sbt-tpolecat/issues/134.
+Test / tpolecatExcludeOptions += ScalacOptions.warnNonUnitStatement


This is the main option that we need to reproduce the but, however imperative ScalaTest assertions will raise a lot of warnings if it is on. What I did was to enable it for Compile but disable it for Test and move the annotated components from test into main.

steinybot · 2023-03-30T02:15:39Z

tests/src/test/scala-2/slinky/core/annotations/ReactAnnotatedComponentTest.scala

@@ -312,7 +49,7 @@ class ReactAnnotatedComponentTest extends AsyncFunSuite {
  }

  test("Can construct a component taking Unit props with refs and key") {
-    val element: ReactElement = NoPropsComponent.withKey("hi").withRef((r: js.Object) => {})
+    val element: ReactElement = NoPropsComponent.withKey("hi").withRef((_: js.Object) => {})


I had to fix a bunch of unused warnings.

steinybot · 2023-03-30T02:16:35Z

web/build.sbt

-scalacOptions -= "-Xfatal-warnings"
+tpolecatDevModeOptions ~= { opts =>
+  opts.filterNot(Set(
+    ScalacOptions.privateKindProjector


This does not play nice with *.

shadaj

This looks great! I think for adding sbt-tpolecat, maybe we can just add that to the tests? I'm not super familiar using it personally, but I think it makes sense to test the macro-generated code with it enabled.

steinybot · 2023-04-04T02:22:17Z

I think for adding sbt-tpolecat, maybe we can just add that to the tests? I'm not super familiar using it personally, but I think it makes sense to test the macro-generated code with it enabled.

Unfortunately it is an AutoPlugin so it is kinda annoying to disable but it can be done. I'll have to add .disablePlugins(TpolecatPlugin) to all the projects except for test and then put the options back on librarySettings. Scala 3 doesn't like redundant options so I'd have to go an filter them out again from test, also doable but might end up being even more of a nuisance than leaving TpolecatPlugin enabled. Shall I go ahead with this?

shadaj · 2023-04-04T02:33:12Z

Ahh I see, in that case let's just leave it as is. Looks like there are some failing lints, but other than that good to go!

steinybot · 2023-05-10T22:28:17Z

@shadaj I think this should be good now. The build didn't rerun for whatever reason.

shadaj · 2023-05-17T07:41:36Z

Looks like there's a merge conflict, but looks good to go otherwise!

…value

shadaj · 2023-05-23T22:24:37Z

@steinybot hmm it seems that we still have discarded non-Unit value errors

steinybot · 2023-05-23T23:13:13Z

Woops. Ok I'm going to dig a bit deeper.

So I found some more history around why those null.asInstanceOfs are there. Looks like it was to fix unused import warnings (which we still inexplicably see now and then BTW) #112.

steinybot · 2023-05-23T23:15:25Z

I suspect the bump thing from #188 may have been related to this discarded non-unit value issue. I'll look to solve both these unused import and discarded non-unit warnings another way.

steinybot · 2023-05-24T00:22:36Z

Oh so the issue was that q"null.asInstanceOf[Props]: Unit was generating:

    ({
      null.asInstanceOf[slinky.core.annotations.TestComponent.Props];
      ()
    }: Unit);

This is putting an extra block with a unit value in there so there is still a discarded value.

I tried using the AST API rather than quasiquotes but I got the same thing.

The solution is to use:

locally {
  val _ = null.asInstanceOf[Props]
}

shadaj · 2023-07-13T17:02:20Z

Sorry, only just got to catching up on this PR! Could you merge/rebase with master? It seems CI isn't running for some reason.

shadaj · 2023-07-17T01:17:51Z

Let's try merging this, GitHub actions should pick it up on main at least.

steinybot added 9 commits March 30, 2023 09:16

Add sbt-tpolecat to tests

54a59a2

Fix warnings in tests

8adb0e5

Fix warnings in tests

7665911

Fix scalacOptions

2f68335

Increase sbt max memory

4e1f7d5

Remove kind projector

6b952b9

Update to Scala 2.13.10

b9f1b37

Disable non-unit statement warning in tests

b5d7410

Fix non-unit statements in @react macro

503afee

steinybot commented Mar 30, 2023

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I kept getting OOME's in sbt trying to run the tests.

steinybot commented Mar 30, 2023

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steinybot changed the title ~~React macro unused value~~ Explicitly discard non-unit values in @react macro Mar 30, 2023

shadaj requested changes Apr 4, 2023

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steinybot added 3 commits April 5, 2023 09:45

Add Scala 3 scalafix config

dc6f2bd

Run scalafix

81cf741

Fix style

0ae9f40

Merge remote-tracking branch 'upstream/main' into react-macro-unused-…

90a04a3

…value

steinybot added 3 commits May 25, 2023 13:01

Fix discarded non-unit statements in @react macro

588095b

Move annotated components back to the tests

294f528

Disable fatal warnings for Scala 3 build

dcc56d3

shadaj approved these changes Jul 13, 2023

View reviewed changes

shadaj merged commit 19408aa into shadaj:main Jul 17, 2023

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Explicitly discard non-unit values in @react macro #630

Explicitly discard non-unit values in @react macro #630

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Explicitly discard non-unit values in @react macro #630

Explicitly discard non-unit values in @react macro #630

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