No recompilation if the dependencies have changed

[anthonyvdotbe]

Affected version

3.15.0

Bug description

To reproduce:

• unzip sample.zip
• run mvn compile
• delete the dependencies section from the POM
• run mvn compile

Expected: the last step fails because the dependencies have changed and thus recompilation is triggered and thus compilation fails due to missing classes

Actual: the last step succeeds and the compiler plugin says "Nothing to compile - all classes are up to date."