Various uses of contains(string), followed by substring(string.length)

• Type: Bug
• Status: Ready for Testing
• Resolution: Fixed
• Affects Version/s: 7.0.X, 7.1.X, 7.2.X, Master
• Fix Version/s: 7.0.0 DXP FP93, 7.0.10.14 DXP SP14, 7.0.X, 7.1.10 DXP FP18, 7.1.10.5 SP5, 7.1.X, 7.2.10 DXP FP6, 7.2.X, 7.3.3 CE GA4, 7.3.10 DXP GA1, Master
• Component/s: Util
• Labels:
  • liferay-dxp-70-sp14
  • liferay-dxp-71-sp5
  • liferay-fixpack-de-93-7010
  • liferay-fixpack-dxp-18-7110
  • liferay-fixpack-dxp-6-7210
• Branch Version/s:
  7.2.x, 7.1.x, 7.0.x
• Backported to Branch:
  Committed
• Fix Priority: 1
• Git Pull Request: https://github.com/hhuijser/liferay-portal/pull/4379

There are multiple places in Liferay which have the following pattern:

if (variableName1.contains(variableName2)) {
   variableName3 = variableName1.substring(variableName2.length);
}

However, this code pattern is incorrect, because "contains" will return true, regardless of the starting position of the substring, but we actually want to only run substring if it "startsWith" the given substring.

We can find the files affected by this pattern with the following Bash script:

for file in $(git ls-files | grep -F .java | xargs grep -l 'substring\([^, ]*\.length\)'); do
  for var_name in $(grep -o 'substring\([^, ]*\.length\)' ${file} | cut -d'(' -f 2 | sed 's/\.length$//g'); do
    has_contains=$(grep -F "contains(${var_name})" ${file})
    if [ "" != "${has_contains}" ]; then
      echo ${file}
    fi
  done
done

It doesn't have any actual issues, but because it's technically incorrect, we should address it.