Xpp3DomBuilder.createXmlReader: remove thread-unsafe system property manipulation - #393
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elharo wants to merge 3 commits into
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Xpp3DomBuilder.createXmlReader: remove thread-unsafe system property manipulation#393elharo wants to merge 3 commits into
elharo wants to merge 3 commits into
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Pull request overview
Removes thread-unsafe manipulation of the global org.xml.sax.driver system property from Xpp3DomBuilder.createXmlReader(), addressing a race condition in multi-threaded environments (e.g., Maven parallel builds) as described in issue #392.
Changes:
- Removed clear/restore of
org.xml.sax.driverfromcreateXmlReader()and now directly falls back toXMLReaderFactory.createXMLReader(). - Added a regression test asserting that
Xpp3DomBuilder.build(...)does not modifyorg.xml.sax.driver.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
| File | Description |
|---|---|
| src/main/java/org/apache/maven/shared/utils/xml/Xpp3DomBuilder.java | Removes thread-unsafe global system property manipulation when creating an XMLReader. |
| src/test/java/org/apache/maven/shared/utils/xml/Xpp3DomBuilderTest.java | Adds a regression test to ensure build() does not change the SAX driver system property. |
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| @Test | ||
| public void buildDoesNotModifySaxDriverProperty() { | ||
| String key = "org.xml.sax.driver"; | ||
| String original = System.getProperty(key); | ||
| Xpp3DomBuilder.build(new StringReader("<root/>")); | ||
| assertEquals(original, System.getProperty(key)); | ||
| } |
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Xpp3DomBuilder.createXmlReader()clears and restores the globalorg.xml.sax.driversystem property without synchronization (lines 119-129). In a multi-threaded environment like Maven parallel builds, one thread's clear/restore sequence interferes with other threads' reads of the same property. The code's own comment acknowledges: "There's a 'slight' problem with this an parallel maven: It does not work ;)"The method already tries to directly instantiate
com.sun.org.apache.xerces.internal.parsers.SAXParserfirst — which succeeds on all Oracle/OpenJDK JVMs. The system property manipulation fallback is both unnecessary and harmful.Fix: Removed the system property manipulation entirely. If the direct instantiation fails, falls through to
XMLReaderFactory.createXMLReader()without modifying any global state.Fixes #392