scala.lang.correctness.positive-number-index-of.positive-number-index-of

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LGPL Commons Clause
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Flags scala code that look for values that are greater than 0. This ignores the first element, which is most likely a bug. Instead, use indexOf with -1. If the intent is to check the inclusion of a value, use the contains method instead.

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Defintion

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rules:
  - id: positive-number-index-of
    metadata:
      category: correctness
      technology:
        - scala
      license: Commons Clause License Condition v1.0[LGPL-2.1-only]
      references:
        - https://blog.codacy.com/9-scala-security-issues/
      confidence: MEDIUM
    message: Flags scala code that look for values that are greater than 0. This
      ignores the first element, which is most likely a bug. Instead, use
      indexOf with -1. If the intent is to check the inclusion of a value, use
      the contains method instead.
    severity: WARNING
    languages:
      - scala
    patterns:
      - pattern-either:
          - patterns:
              - pattern: |
                  $OBJ.indexOf(...) > $VALUE
              - metavariable-comparison:
                  metavariable: $VALUE
                  comparison: $VALUE >= 0
          - patterns:
              - pattern: |
                  $OBJ.indexOf(...) >= $SMALLERVAL
              - metavariable-comparison:
                  metavariable: $SMALLERVAL
                  comparison: $SMALLERVAL > 0

Examples

positive-number-index-of.scala

class Test {
   def bad1(){
      val color = "blue"
      val strings = List("blue", "bob")
      // ruleid: positive-number-index-of
      if(strings.indexOf(color) > 0){
         println("This is if statement");
      }
   }

   def bad2(){
      val name = "bob"
      // ruleid: positive-number-index-of
      if(name.indexOf("b") > 2){
         println("This is if statement");
      }
   }

   def ok1() {
      val color = "blue"
      val strings = List("blue", "bob")
      // ok: positive-number-index-of
      if(strings.indexOf(color) > -1){
         println("This is if statement");
      }
   }

   def ok2(){
      val name = "bob"
      // ok: positive-number-index-of
      if(name.indexOf("b") >= 0){
         println("This is if statement");
      }
   }
}