Attempt to detect system property mangling prior to loading ByteBuddy. #3164
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If the user stubs their System properties (e.g. to test code that handles System properties to determine the platform), then they may unexpectedly hit the issue that ByteBuddy will attempt to fork a subprocess upon being installed, and that relies on the JVM Process class. Internally, the Process class makes a call to 'System.getProperty(os.name)', which results in a NullPointerException being raised if the property does not exist. When this exception occurs, it bubbles up to Mockito in the shape of a very confusing error message, which we should ideally try to avoid. This change adds a check for this edge case prior to loading ByteBuddy so that a meaningful error message can be raised that instructs the user on how to mitigate this issue.
Codecov ReportAttention:
Additional details and impacted files@@ Coverage Diff @@
## main #3164 +/- ##
============================================
- Coverage 85.53% 85.50% -0.03%
Complexity 2914 2914
============================================
Files 334 334
Lines 8861 8864 +3
Branches 1096 1097 +1
============================================
Hits 7579 7579
- Misses 993 995 +2
- Partials 289 290 +1
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If the user stubs their System properties (e.g. to test code that handles System properties to determine the platform), then they may unexpectedly hit the issue that ByteBuddy will attempt to fork a subprocess upon being installed, and that relies on the JVM Process class. Internally, the Process class makes a call to 'System.getProperty(os.name)', which results in a NullPointerException being raised if the property does not exist.
When this exception occurs, it bubbles up to Mockito in the shape of a very confusing error message, which we should ideally try to avoid.
This change adds a check for this edge case prior to loading ByteBuddy so that a meaningful error message can be raised that instructs the user on how to mitigate this issue.
Example reproduction:
Current behaviour:
Using FernFlower, the code at
java.base/java.lang.ProcessImpl.<clinit>(ProcessImpl.java:170)is the following:This is probably technically a JRE bug, as it is making the expectation that a mutable global singleton is not being mutated in a specific way, but it probably makes sense to check for it here for now to prevent confusing error messages on Mockito's side of things and to prevent spurious issues being raised against the project.