Fix NoClassDefFoundError during analysis of inner classes#1660
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Fixes sbt/sbt#117 ClassToAPI used Java reflection (c.getClasses, c.getDeclaredClasses) to discover inner classes during post-compile analysis. When an inner class references types not on the classpath (e.g. optional dependencies like JBoss VFS in Spring), these reflection calls throw NoClassDefFoundError, crashing compilation. The fix tries reflection first (preserving exact existing semantics), and falls back to parsing the classfile's InnerClasses attribute when reflection fails. The fallback logs a warning and gracefully skips any inner classes that can't be loaded. This is a revival of sbt#516 by @eed3si9n, rebased onto the current codebase with tests added. Co-Authored-By: Eugene Yokota <[email protected]> Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>
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Replace getDeclaredClasses/getClasses with classfile InnerClasses attribute parsing. Load each inner class individually so one broken class doesn't take out the rest. Walk parent classfiles for inherited public inner classes. Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>
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Summary
Fixes sbt/sbt#117 — the oldest open bug in sbt, filed July 22, 2011.
ClassToAPIused Java reflection (c.getClasses,c.getDeclaredClasses) to discover inner classes during post-compile analysis. When an inner class references types not on the classpath (e.g., optional dependencies like JBoss VFS in Spring), these reflection calls throwNoClassDefFoundError, crashing compilation.InnerClassesattribute directly from bytecode instead of using reflection, and gracefully skip any inner classes that can't be loaded via the classloader.ClassToAPI.processsucceeds. Also added parser-level tests forInnerClassesattribute parsing.This is a revival of #516 by @eed3si9n, rebased onto the current codebase with the tests that were requested at the time.
Changes
ClassFile.scalainnerClassesto trait,InnerClassInfocase class,isInnerClassesonAttributeInfoParser.scalaInnerClassesclassfile attribute intoArray[InnerClassInfo]ClassToAPI.scalaParserSpecification.scalaInnerClassesattribute parsingClassToAPISpecification.scalaTest plan
zincClassfile3/testtests pass (26/26)zincApiInfo3/testtests pass (42/42), including existing inner class extraction testsClassToAPI.processdoesn't throw when inner class references a missing typeInnerClassesattribute from JDK classes🤖 Generated with Claude Code