[java] CyclomaticComplexityRule counts ?-operator twice

[dreniers]

Affects PMD Version: 6.5.0

Rule: category/java/design.xml/CyclomaticComplexity

Description: CyclomaticComplexityRule counts conditional ternary operator twice. I believe this is incorrect, as it just adds one code path and can be rewritten as an if-else statement which just has complexity 1.

Code Sample demonstrating the issue:

  public void get() {
    final String a = b == null ? c : d;
  }

Running PMD through: CLI

Example of output:

15:07:55 E:\dev\pmd-cyclox>more TernaryOperator.java & echo --- & more ruleset-for-cyclox.xml & echo --- & pmd-bin-6.5.0\bin\pmd.bat -f xml -R ruleset-for-cyclo
x.xml -d TernaryOperator.java
class MyClass {
  public void run(String b, String c) {
    final String a = b == null ? c : b;
  }
}
---
<?xml version="1.0"?>

<ruleset name="Custom Rules"
    xmlns="http://pmd.sourceforge.net/ruleset/3.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://pmd.sourceforge.net/ruleset/3.0.0 http://pmd.sourceforge.net/ruleset_3_0_0.xsd">
  <description>
Custom rules
  </description>

  <rule
   ref="category/java/design.xml/CyclomaticComplexity"
   >
   <properties>
        <property name="methodReportLevel" value="1"/>
    </properties>
  </rule>

</ruleset>
---
jun 28, 2018 3:07:56 PM net.sourceforge.pmd.PMD processFiles
WARNING: This analysis could be faster, please consider using Incremental Analysis: https://pmd.github.io/pmd-6.5.0/pmd_userdocs_incremental_analysis.html
<?xml version="1.0" encoding="UTF-8"?>
<pmd xmlns="http://pmd.sourceforge.net/report/2.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://pmd.sourceforge.net/report/2.0.0 http://pmd.sourceforge.net/report_2_0_0.xsd"
    version="6.5.0" timestamp="2018-06-28T15:07:56.983">
<file name="E:\dev\pmd-cyclox\TernaryOperator.java">
<violation beginline="2" endline="4" begincolumn="10" endcolumn="3" rule="CyclomaticComplexity" ruleset="Design" class="MyClass" method="run" externalInfoUrl="h
ttps://pmd.github.io/pmd/pmd_rules_java_design.html#cyclomaticcomplexity" priority="3">
The method 'run(String, String)' has a cyclomatic complexity of 3.
</violation>
</file>
</pmd>

PMD reports a complexity of 3, where I believe it should be 2: one for the method entry, and one for the ?-operator.