null substitution in array with concatenation

[yury-skobov]

library version: 1.4.1

I get a BugOrBroken exception on the following snippet:

    val hocon =
      """
         |tail = [ 2 ]
         |front = [
         |  {
         |    foo = 1
         |    foo = ${?bar}
         |  }
         |] ${tail}
         |""".stripMargin

    ConfigFactory.parseString(hocon).resolve()

Any of the following allow the snippet to complete without error:

• Removing foo = 1.
• Removing foo = ${?bar}.
• Inlining tail (i.e. front = [ ... ] [ 2 ]).

Top of the stack trace:

[info]   com.typesafe.config.ConfigException$BugOrBroken: SimpleConfigObject.replaceChild did not find SimpleConfigList([{"foo":1,"foo":${?bar}}]) in SimpleConfigObject({"front":[{"foo":1,"foo":${?bar}}]${tail},"tail":[2]})
[info]   at com.typesafe.config.impl.SimpleConfigObject.replaceChild(SimpleConfigObject.java:216)
[info]   at com.typesafe.config.impl.SimpleConfigObject.replaceChild(SimpleConfigObject.java:26)
[info]   at com.typesafe.config.impl.ResolveSource.replace(ResolveSource.java:192)
[info]   at com.typesafe.config.impl.ResolveSource.replace(ResolveSource.java:193)
[info]   at com.typesafe.config.impl.ResolveSource.replaceCurrentParent(ResolveSource.java:209)
[info]   at com.typesafe.config.impl.ResolveSource.replaceWithinCurrentParent(ResolveSource.java:240)
[info]   at com.typesafe.config.impl.ConfigDelayedMerge.resolveSubstitutions(ConfigDelayedMerge.java:110)
[info]   at com.typesafe.config.impl.ConfigDelayedMerge.resolveSubstitutions(ConfigDelayedMerge.java:59)

[conderls]

failed to reproduce the error with typesafe 1.3.4, it just works:

scala> import com.typesafe.config.ConfigFactory
import com.typesafe.config.ConfigFactory

scala> val hocon =
     |       """
     |          |tail = [ 2 ]
     |          |front = [
     |          |  {
     |          |    foo = 1
     |          |    foo = ${?bar}
     |          |  }
     |          |] ${tail}
     |          |""".stripMargin
hocon: String =
"
tail = [ 2 ]
front = [
  {
    foo = 1
    foo = ${?bar}
  }
] ${tail}
"

scala> ConfigFactory.parseString(hocon).resolve()
res0: com.typesafe.config.Config = Config(SimpleConfigObject({"front":[{"foo":1},2],"tail":[2]}))