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  1. Rules Repository
  2. RSPEC-1871

Two branches in a conditional structure should not have exactly the same implementation

    Details

    • Type: Code Smell Detection
    • Status: Active
    • Resolution: Unresolved
    • Labels:
    • Message:
      The code of this ["case"|branch] is a duplicate; refactor so that all ["case" blocks|branches] are unique.
    • Highlighting:
      Hide
      • Primary: 2nd block
      • Additional: 1st block
        • Message: Original

      All characters in both blocks should be underlined.

      Show
      Primary: 2nd block Additional: 1st block Message: Original All characters in both blocks should be underlined.
    • Default Severity:
      Major
    • Impact:
      Low
    • Likelihood:
      High
    • Default Quality Profiles:
      Sonar way
    • Targeted languages:
      PL/I, VB6
    • Covered Languages:
      ABAP, C#, C, C++, Cobol, Flex, Go, Java, JavaScript, Kotlin, Objective-C, PHP, PL/SQL, Python, RPG, Ruby, Scala, Swift, T-SQL, TypeScript, VB.Net
    • Irrelevant for Languages:
      HTML, XML
    • Remediation Function:
      Constant/Issue
    • Constant Cost:
      10min
    • Analysis Level:
      Syntactic Analysis
    • Analysis Scope:
      Main Sources
    • Common Rule:
      Yes
    • CPPCheck:
      duplicateBranch
    • ESLint-SonarJS:
      no-duplicated-branches
    • FindBugs:
      DB_DUPLICATE_SWITCH_CLAUSES, DB_DUPLICATE_BRANCHES
    • ReSharper:
      ConditionalTernaryEqualBranch

      Description

      Having two cases in a switch statement or two branches in an if chain with the same implementation is at best duplicate code, and at worst a coding error. If the same logic is truly needed for both instances, then in an if chain they should be combined, or for a switch, one should fall through to the other.

      Noncompliant Code Example

      switch (i) {
  case 1: 
    doFirstThing();
    doSomething();
    break;
  case 2: 
    doSomethingDifferent();
    break;
  case 3:  // Noncompliant; duplicates case 1's implementation
    doFirstThing();
    doSomething(); 
    break;
  default: 
    doTheRest();
}

if (a >= 0 && a < 10) {
  doFirstThing();
  doTheThing();
}
else if (a >= 10 && a < 20) {
  doTheOtherThing();
}
else if (a >= 20 && a < 50) {
  doFirstThing();
  doTheThing();  // Noncompliant; duplicates first condition
}
else {
  doTheRest(); 
}

      Exceptions

      Blocks in an if chain that contain a single line of code are ignored, as are blocks in a switch statement that contain a single line of code with or without a following break.

      if (a == 1) {
  doSomething();  //no issue, usually this is done on purpose to increase the readability
} else if (a == 2) {
  doSomethingElse();
} else {
  doSomething();
}

      But this exception does not apply to if chains without else-s, or to switch-es without default clauses when all branches have the same single line of code. In case of if chains with else-s, or of switch-es with default clauses, rule S3923 raises a bug. 

      if (a == 1) {
  doSomething();  //Noncompliant, this might have been done on purpose but probably not
} else if (a == 2) {
  doSomething();
}

        Attachments

          Issue Links

          is implemented by

          Bug - A problem which impairs or prevents the functions of the product. SONARPY-477 S1871: Raise only one issue when more than one code block is duplicated

          • Major - Major loss of function.
          • Closed

          New Feature - A new feature of the product, which has yet to be developed. SONARPLI-181 Rule: Two branches in a conditional structure should not have exactly the same implementation

          • Major - Major loss of function.
          • Open

          New Feature - A new feature of the product, which has yet to be developed. SONARVBSIX-261 Rule: Two branches in a conditional structure should not have exactly the same implementation

          • Major - Major loss of function.
          • Open

          New Feature - A new feature of the product, which has yet to be developed. CPP-806 Rule: Two cases in the same "switch" should not have exactly the same implementation

          • Major - Major loss of function.
          • Closed

          New Feature - A new feature of the product, which has yet to be developed. SLVS-1010 Add matching branches in if-else chain rule

          • Major - Major loss of function.
          • Closed

          New Feature - A new feature of the product, which has yet to be developed. SONARCOBOL-1187 Rule: Two branches in the same conditional structure should not have exactly the same implementation

          • Major - Major loss of function.
          • Closed

          New Feature - A new feature of the product, which has yet to be developed. SONARPHP-431 Rule: Two branches in the same conditional structure should not have exactly the same implementation

          • Major - Major loss of function.
          • Closed

          New Feature - A new feature of the product, which has yet to be developed. SONARPLSQL-602 Rule: Two branches in the same conditional structure should not have exactly the same implementation

          • Major - Major loss of function.
          • Closed

          New Feature - A new feature of the product, which has yet to be developed. SONARRPG-117 Rule: Two branches in the same conditional structure should not have exactly the same implementation

          • Major - Major loss of function.
          • Closed

          New Feature - A new feature of the product, which has yet to be developed. SONARSLANG-7 Rule S1871: Two branches in a conditional structure should not have exactly the same implementation

          • Major - Major loss of function.
          • Closed

          New Feature - A new feature of the product, which has yet to be developed. SONARSLANG-154 Enable in Ruby rule S1871 (DuplicateBranchCheck)

          • Major - Major loss of function.
          • Closed

          New Feature - A new feature of the product, which has yet to be developed. SONARSLANG-217 [Scala] Enable Rule: S1871 Two branches in a conditional structure should not have exactly the same implementation

          • Major - Major loss of function.
          • Closed

          New Feature - A new feature of the product, which has yet to be developed. SONARSLANG-323 [Apex] Enable Rule: S1871 Two branches in a conditional structure should not have exactly the same implementation

          • Major - Major loss of function.
          • Closed

          New Feature - A new feature of the product, which has yet to be developed. SONARSWIFT-61 Rule: Two branches in the same conditional structure should not have exactly the same implementation

          • Major - Major loss of function.
          • Closed

          New Feature - A new feature of the product, which has yet to be developed. SONARTSQL-18 Rule: Two branches in a conditional structure should not have exactly the same implementation

          • Major - Major loss of function.
          • Closed

          Task - A task that needs to be done. SONARSLANG-424 [Go] Enable rules about identical branches

          • Major - Major loss of function.
          • Closed

          Improvement - An improvement or enhancement to an existing feature or task. SONARFLEX-58 S1871: Extend rule on if-statements

          • Major - Major loss of function.
          • Open

          Improvement - An improvement or enhancement to an existing feature or task. SONARJS-444 Improve DuplicateBranchImplementation (S1871) : cover ternary operator

          • Major - Major loss of function.
          • Closed

          Improvement - An improvement or enhancement to an existing feature or task. SONARSWIFT-161 Update S1871 to cover ternary operator

          • Major - Major loss of function.
          • Closed
          is related to

          New Feature - A new feature of the product, which has yet to be developed. SONARPY-299 Rule S3923 (with update of S1871): All branches in a conditional structure should not have exactly the same implementation

          • Major - Major loss of function.
          • Closed

          New Feature - A new feature of the product, which has yet to be developed. SONARSWIFT-275 Rule S3923: All branches in a conditional structure should not have exactly the same implementation

          • Major - Major loss of function.
          • Closed

          Improvement - An improvement or enhancement to an existing feature or task. SONARPY-123 Update S1871 to cover ternary operator

          • Major - Major loss of function.
          • Closed

          Improvement - An improvement or enhancement to an existing feature or task. SONARPY-256 Update S1871 to cover single line of code exception

          • Major - Major loss of function.
          • Closed
          links to

          Web Link is implemented by sonar-go/issues/94

          1.
          		 COBOL RSPEC-2585 Language-Specification Active Unassigned
          2.
          		 Swift RSPEC-2633 Language-Specification Active Unassigned
          3.
          		 Python RSPEC-2705 Language-Specification Active Unassigned
          4.
          		 PHP RSPEC-2863 Language-Specification Active Unassigned
          5.
          		 RPG RSPEC-2868 Language-Specification Active Unassigned
          6.
          		 JavaScript RSPEC-3022 Language-Specification Active Unassigned
          7.
          		 ABAP RSPEC-3703 Language-Specification Active Unassigned
          8.
          		 VB.NET RSPEC-3714 Language-Specification Active Unassigned
          9.
          		 C# RSPEC-3716 Language-Specification Active Unassigned
          10.
          		 T-SQL RSPEC-4100 Language-Specification Active Unassigned
          11.
          		 PL/SQL RSPEC-4240 Language-Specification Active Unassigned
          12.
          		 Go RSPEC-4590 Language-Specification Active Unassigned
          13.
          		 Ruby RSPEC-4763 Language-Specification Active Unassigned
          14.
          		 Kotlin RSPEC-4799 Language-Specification Active Unassigned
          15.
          		 Scala RSPEC-4930 Language-Specification Active Unassigned
          16.
          		 Apex RSPEC-5002 Language-Specification Active Unassigned
          17.
          		 C-Family RSPEC-5517 Language-Specification Active Unassigned

            Activity

              People

              • Assignee:
                Unassigned
                Reporter:
                freddy.mallet Freddy Mallet (Inactive)
              • Votes:
                0 Vote for this issue
                Watchers:
                2 Start watching this issue

                Dates

                • Created:
                  Updated: