Jacoco agent is added to mutation minion

[eorloff]

After updating to PiTest 1.9.3 we are seeing RUN_ERROR when running PiTest. I have tested with PiTest 1.9.2 that does not fail.

When running with verbose logging I get the following error

stdout  : Hotswap loader jdk.internal.loader.ClassLoaders$AppClassLoader@5e2de80c
stdout  : java.lang.UnsupportedOperationException: class redefinition failed: attempted to delete a method
stdout  :       at java.instrument/sun.instrument.InstrumentationImpl.redefineClasses0(Native Method)
stdout  :       at java.instrument/sun.instrument.InstrumentationImpl.redefineClasses(InstrumentationImpl.java:195)
stdout  :       at org.pitest.boot.HotSwapAgent.hotSwap(HotSwapAgent.java:46)
stdout  :       at org.pitest.mutationtest.execute.HotSwap.apply(HotSwap.java:30)
stdout  :       at org.pitest.mutationtest.execute.HotSwap.apply(HotSwap.java:9)
stdout  :       at org.pitest.mutationtest.execute.MutationTestWorker.handleCoveredMutation(MutationTestWorker.java:149)
stdout  :       at org.pitest.mutationtest.execute.MutationTestWorker.handleMutation(MutationTestWorker.java:126)
stdout  :       at org.pitest.mutationtest.execute.MutationTestWorker.processMutation(MutationTestWorker.java:108)
stdout  :       at org.pitest.mutationtest.execute.MutationTestWorker.run(MutationTestWorker.java:79)
stdout  :       at org.pitest.mutationtest.execute.MutationTestMinion.run(MutationTestMinion.java:99)
stdout  :       at org.pitest.mutationtest.execute.MutationTestMinion.main(MutationTestMinion.java:148)
stderr  : 19.16.45 PIT >> WARNING : Error during mutation test
stderr  : java.lang.UnsupportedOperationException: class redefinition failed: attempted to delete a method
stderr  :       at java.instrument/sun.instrument.InstrumentationImpl.redefineClasses0(Native Method)
stderr  :       at java.instrument/sun.instrument.InstrumentationImpl.redefineClasses(InstrumentationImpl.java:195)
stderr  :       at org.pitest.boot.HotSwapAgent.hotSwap(HotSwapAgent.java:46)
stderr  :       at org.pitest.mutationtest.execute.HotSwap.apply(HotSwap.java:30)
stderr  :       at org.pitest.mutationtest.execute.HotSwap.apply(HotSwap.java:9)
stderr  :       at org.pitest.mutationtest.execute.MutationTestWorker.handleCoveredMutation(MutationTestWorker.java:149)
stderr  :       at org.pitest.mutationtest.execute.MutationTestWorker.handleMutation(MutationTestWorker.java:126)
stderr  :       at org.pitest.mutationtest.execute.MutationTestWorker.processMutation(MutationTestWorker.java:108)
stderr  :       at org.pitest.mutationtest.execute.MutationTestWorker.run(MutationTestWorker.java:79)
stderr  :       at org.pitest.mutationtest.execute.MutationTestMinion.run(MutationTestMinion.java:99)
stderr  :       at org.pitest.mutationtest.execute.MutationTestMinion.main(MutationTestMinion.java:148)
19.16.45 PIT >> FINE : Exit code was - UNKNOWN_ERROR
19.16.45 PIT >> WARNING : Minion exited abnormally due to RUN_ERROR
19.16.45 PIT >> FINE : Setting 1 unfinished runs to RUN_ERROR state

Digging into the changes between 1.9.2 and 1.9.3 I have tried modifying the argLine parameter and this seems to be the problematic change. The JaCoCo agent is accidentally enabled if the argLine has not been explicitly set. See below.

Without setting ArgLine:
"C:\Program Files\Eclipse Foundation\jdk-17.0.0.35-hotspot\bin\java" -Djava.awt.headless=true -javaagent:C:\\Users\\ebo\\.m2\\repository\\org\\jacoco\\org.jacoco.agent\\0.8.8\\org.jacoco.agent-0.8.8-runtime.jar=destfile=C:\\Users\\ebo\\src\\pbc\\core\\contract\\target\\jacoco.exec -javaagent:C:\Users\ebo\AppData\Local\Temp\16593783398090350423204432893312611738940937464797.jar "-Dclassworlds.conf=C:/Program Files (x86)/apache-maven-3.6.3/bin/m2.conf" "-Dmaven.home=C:/Program Files (x86)/apache-maven-3.6.3" "-Dlibrary.jansi.path=C:/Program Files (x86)/apache-maven-3.6.3/lib/jansi-native" -Dmaven.multiModuleProjectDirectory=C:/Users/ebo/src/pbc/core/contract org.pitest.mutationtest.execute.MutationTestMinion 54271

With ArgLine set with -DargLine='':
"C:\Program Files\Eclipse Foundation\jdk-17.0.0.35-hotspot\bin\java" -Djava.awt.headless=true -javaagent:C:\Users\ebo\AppData\Local\Temp\1659378250879088791656585998567406604286261976640.jar "-Dclassworlds.conf=C:/Program Files (x86)/apache-maven-3.6.3/bin/m2.conf" "-Dmaven.home=C:/Program Files (x86)/apache-maven-3.6.3" "-Dlibrary.jansi.path=C:/Program Files (x86)/apache-maven-3.6.3/lib/jansi-native" -Dmaven.multiModuleProjectDirectory=C:/Users/ebo/src/pbc/core/contract org.pitest.mutationtest.execute.MutationTestMinion 53977

With PiTest 1.9.2
"C:\Program Files\Eclipse Foundation\jdk-17.0.0.35-hotspot\bin\java" -Djava.awt.headless=true -javaagent:C:\Users\ebo\AppData\Local\Temp\165937861524900867023834234013112109174415442643105.jar "-Dclassworlds.conf=C:/Program Files (x86)/apache-maven-3.6.3/bin/m2.conf" "-Dmaven.home=C:/Program Files (x86)/apache-maven-3.6.3" "-Dlibrary.jansi.path=C:/Program Files (x86)/apache-maven-3.6.3/lib/jansi-native" -Dmaven.multiModuleProjectDirectory=C:/Users/ebo/src/pbc/core/contract org.pitest.mutationtest.execute.MutationTestMinion 51602

[hcoles]

Thanks for the report.

The options here are limited as prior to the change other users had the opposite problem (important argline arguments weren't picked up by default).

Possibilities include

1. Toggle argline inclusion on/off with a flag (but this just moved the problem so one group or another has to debug in order to switch off the defauilt value).
2. If jacoco is on the argline throw an error telling the user to remove it
3. Try and automatically remove jacoco from the argline (or otherwise disable it)

Option 3 seems best, but would be easy to mess up as there will be some variation in what the argline looks like.

Option 2 should be straigthforward

Not sure Option 1 really solves or improves anything.
5. Try and remove jacoco from the argline