com.sksamuel.scapegoat.inspections.controlflow.WhileTrue.scala Maven / Gradle / Ivy

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package com.sksamuel.scapegoat.inspections.controlflow

import com.sksamuel.scapegoat._

/**
 * @author Stephen Samuel
 */
class WhileTrue
    extends Inspection(
      text = "While true loop",
      defaultLevel = Levels.Warning,
      description = "Checks for code that uses a while(true) or do {...} while(true) block.",
      explanation = "A (do) while true loop is unlikely to be meant for production."
    ) {

  def inspector(context: InspectionContext): Inspector =
    new Inspector(context) {
      override def postTyperTraverser =
        new context.Traverser {

          import context.global._

          override def inspect(tree: Tree): Unit = {
            tree match {
              case LabelDef(name, _, If(cond, _, _)) if isWhile(name) && isConstantCondition(cond) =>
                context.warn(tree.pos, self, tree.toString.take(500))
              case LabelDef(name, _, Block(_, If(cond, _, _)))
                  if isWhile(name) && isConstantCondition(cond) =>
                context.warn(tree.pos, self, tree.toString.take(500))
              case _ => continue(tree)
            }
          }

          private def isConstantCondition(tree: Tree): Boolean =
            tree match {
              case Literal(Constant(true)) => true
              case _                       => false
            }

          private def isWhile(name: TermName): Boolean =
            name.toString.startsWith("while$") || name.toString.startsWith("doWhile$")
        }
    }
}