Resolve Pitest Issues - IllegalImportCheck (1)

[rnveach]

Child issue of #7797 ,

checkstyle/.ci/pitest.sh

Line 82 in abf829f

"IllegalImportCheck.java.html:<td class='covered'><pre><span class='survived'> if (regexp) {</span></pre></td></tr>"

[akki111singh]

Hey ! Have you started worked on this isuue! if not can you please do the other one Resolve Pitest Issues - IllegalImportCheck (3) beacause by mistake i worked on this and solved it

[akki111singh]

1.Pitest Report

• Link : https://akki111singh.github.io/pitest-reports/202003201414/com.puppycrawl.tools.checkstyle.checks.imports/IllegalImportCheck.java.html
• Surviving Mutations:
  on line 398 : 3. removed conditional - replaced equality check with true → SURVIVED
  on line 422 : 3. removed conditional - replaced equality check with true → SURVIVED
  on line 440 : 3. removed conditional - replaced equality check with true → SURVIVED
  I am focusing on the third one

2.Mutated Branch

• Hardcoded Mutated commit: 981403f
• Since the mutation was removed conditional - replaced equality check with true → SURVIVEDso therefore the if-else statement was removed to set the execution of all the statements to always true.

3. Regression Report

• Regression Report: https://akki111singh.github.io/diff/index.html

• Modules used in the config file:

   <module name="IllegalImport">
      <property name="regexp" value="true"/>
      <property name="illegalPkgs" value="java\.util"/>
    </module>
    
    <module name="IllegalImport">
      <property name="illegalPkgs" value="java.io, java.sql"/>
    </module>	        
  

4. Regression and code Logic

Although there is no diff found in Regression diff report, I find that the reason why the surviving mutation exists is maybe due to the reason as follows:
When we specify packages or classes to reject, if regexp property is not set, checks if import is the part of package or classes. If regexp property is set, then list of packages or classes will be interpreted as regular expressions and all properties for the match will be used.

If we keep the regexp value always set then it will anyway matches the classes or packages names. So therefore this is the cause of mutation as keeping the regex value always true works as regex will matches the whole package or class name.

Although i figured out a test case :

<property name="illegalClasses" value="java.io.*"/>

Keeping the regex true value here will match all the imports beginning
java.io else it will only match java.io.*,

Adding the above test-case Killed the mutation

Pitest-report : https://akki111singh.github.io/pit-reports2/202003202255/com.puppycrawl.tools.checkstyle.checks.imports/IllegalImportCheck.java.html

on line 440 : 3. removed conditional - replaced equality check with true → SURVIVED -> The mutation is killed

[akki111singh]

@rnveach please review

[rnveach]

Everything looks good to me.

[strkkk]

Fix is merged