testkit: (unclear) error when the test input contains a license header

[jrudolph]

We get the below error while running simple scalafix tests. This error happens during parsing an error (uhoh).

Looking into the real error reveals this:

com.typesafe.config.ConfigException$Parse: String: 2: expecting a close parentheses ')' here, not: '*' (Reserved character '*' is not allowed outside quotes)
  | => oat com.typesafe.config.impl.ConfigDocumentParser$ParseContext.parseError(ConfigDocumentParser.java:201)
        at com.typesafe.config.impl.ConfigDocumentParser$ParseContext.parseError(ConfigDocumentParser.java:197)
	at com.typesafe.config.impl.ConfigDocumentParser$ParseContext.parseKey(ConfigDocumentParser.java:279)
	at com.typesafe.config.impl.ConfigDocumentParser$ParseContext.parseObject(ConfigDocumentParser.java:450)
	at com.typesafe.config.impl.ConfigDocumentParser$ParseContext.parse(ConfigDocumentParser.java:648)
	at com.typesafe.config.impl.ConfigDocumentParser.parse(ConfigDocumentParser.java:14)
	at com.typesafe.config.impl.Parseable.rawParseValue(Parseable.java:262)
	at com.typesafe.config.impl.Parseable.rawParseValue(Parseable.java:250)
	at com.typesafe.config.impl.Parseable.parseValue(Parseable.java:180)
	at com.typesafe.config.impl.Parseable.parseValue(Parseable.java:174)
	at com.typesafe.config.impl.Parseable.parse(Parseable.java:301)
	at com.typesafe.config.ConfigFactory.parseString(ConfigFactory.java:1187)
	at com.typesafe.config.ConfigFactory.parseString(ConfigFactory.java:1197)
	at metaconfig.typesafeconfig.TypesafeConfig2Class$.$anonfun$gimmeConfFromStringFilename$1(scala.scala:17)

because the generated file contains this line:

scalacOptions=-deprecation|-encoding|UTF-8|-unchecked|-Ywarn-dead-code|-Wconf\:msg\=object JavaConverters in package collection is deprecated\:s|-Wconf\:msg\=is deprecated \\(since 2\\.13\\.\:s|-Wconf\:cat\=deprecation&msg\=since Akka 2\\.6\\.\:s|-Wconf\:cat\=deprecation&msg\=since Akka HTTP 10\\.2\\.\:s|-Wconf\:msg\=reached max recursion depth\:s|-release\:8|-Xlint|-Wconf\:cat\=unused-imports&origin\=org.apache.pekko.http.ccompat.*\:s|-Wconf\:cat\=other-match-analysis&msg\=match may not be exhaustive\:s

Solution: Quote strings properly in the generated hocon config. Fail if quoting is not possible.

Reported error:

[info] - org/apache/pekko/http/fix/MigrateToServerBuilderTest.scala *** FAILED *** (588 milliseconds)
[info]   java.util.NoSuchElementException: next on empty iterator
[info]   at scala.collection.Iterator$$anon$19.next(Iterator.scala:973)
[info]   at scala.collection.Iterator$$anon$19.next(Iterator.scala:971)
[info]   at scala.collection.StringOps$$anon$1.next(StringOps.scala:697)
[info]   at scala.collection.StringOps$$anon$1.next(StringOps.scala:695)
[info]   at metaconfig.Position.pretty(Position.scala:25)
[info]   at metaconfig.ConfError$$anon$8.<init>(ConfError.scala:131)
[info]   at metaconfig.ConfError$.parseError(ConfError.scala:131)
[info]   at metaconfig.typesafeconfig.TypesafeConfig2Class$.gimmeSafeConf(TypesafeConfig2Class.scala:68)
[info]   at metaconfig.typesafeconfig.TypesafeConfig2Class$.gimmeConfFromStringFilename(TypesafeConfig2Class.scala:17)
[info]   at metaconfig.Hocon$.fromInput(Hocon.scala:10)
[info]   at metaconfig.Input$InputImplicits.parse(Input.scala:104)
[info]   at metaconfig.Conf$.parseString(Conf.scala:70)
[info]   at scalafix.testkit.RuleTest$.$anonfun$fromPath$1(RuleTest.scala:36)
[info]   at scalafix.testkit.AbstractSemanticRuleSuite.evaluateTestBody(AbstractSemanticRuleSuite.scala:37)
[info]   at scalafix.testkit.AbstractSemanticRuleSuite.$anonfun$runOn$1(AbstractSemanticRuleSuite.scala:97)

[jrudolph]

The issue was something else: in the target input file for the test the /* rule = ... */ comment was below the license headers which led to the issue because the conf parser then tried to parse the license header...

[bjaglin]

Thanks for the report!

The issue was something else: in the target input file for the test the /* rule = ... */ comment was below the license headers which led to the issue because the conf parser then tried to parse the license header...

😅 I renamed the issue accordingly.

The heuristic to detect the semantic comment is indeed quite basic:

scalafix/scalafix-testkit/src/main/scala/scalafix/testkit/SemanticRuleSuite.scala

Lines 31 to 42 in 9e334d1

	def findTestkitComment(tokens: Tokens): Token = {
	tokens
	.find { x =>
	x.is[Token.Comment] && x.syntax.startsWith("/*")
	}
	.getOrElse {
	val input = tokens.headOption.fold("the file")(_.input.syntax)
	throw new IllegalArgumentException(
	s"Missing /* */ comment at the top of $input"
	)
	}
	}

I guess a reasonable fix would be to iterate on all comments until a valid HOCON syntax with a rule or rules key defined is found.

[mdedetrich]

Created a PR at #1832