Fix folderManager NPE issue in WALNode when starting iotdb in a disk-full state

[OneSizeFitsQuorum]

This PR addresses an NPE issue in WALNode creation that occurs when IoTDB starts with a full disk. When the disk is full at startup, the FolderManager initialization in the constructor fails, leaving it null. If disk space is later freed, subsequent WAL node creation attempts fail with NPE because the folderManager is still null.

[Copilot]

Pull request overview

This PR addresses an NPE issue in WALNode creation that occurs when IoTDB starts with a full disk. When the disk is full at startup, the FolderManager initialization in the constructor fails, leaving it null. If disk space is later freed, subsequent WAL node creation attempts fail with NPE because the folderManager is still null.

Key Changes:

• Adds lazy initialization of FolderManager in the createWALNode method to handle recovery after disk space becomes available

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 39.05%. Comparing base (f4d628a) to head (f6b1b7d).
⚠️ Report is 25 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #16869      +/-   ##
============================================
+ Coverage     38.87%   39.05%   +0.17%     
  Complexity      207      207              
============================================
  Files          5021     5021              
  Lines        333052   333150      +98     
  Branches      42389    42390       +1     
============================================
+ Hits         129487   130119     +632     
+ Misses       203565   203031     -534     

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[Copilot]

Pull request overview

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[Copilot]

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[Copilot]

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[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.

Comments suppressed due to low confidence (5)

iotdb-core/datanode/src/test/java/org/apache/iotdb/db/storageengine/dataregion/wal/allocation/FirstCreateStrategyTest.java:256

• Using reflection to access internal state for assertions makes the test brittle and tightly coupled to implementation details. If the field name changes or access control is modified, the test will break. Consider adding a package-private getter method or test hook in the production code to support this test scenario without reflection.

          new MeasurementSchema("s2", dataTypes[1]),
          new MeasurementSchema("s3", dataTypes[2]),
          new MeasurementSchema("s4", dataTypes[3]),
          new MeasurementSchema("s5", dataTypes[4]),
          new MeasurementSchema("s6", dataTypes[5]),
        };

    return new InsertRowNode(
        new PlanNodeId("0"),

iotdb-core/datanode/src/test/java/org/apache/iotdb/db/storageengine/dataregion/wal/allocation/FirstCreateStrategyTest.java:228

• The test name and comment suggest testing behavior when disk is still full, but the test uses non-existent directories instead. Non-existent directories may not accurately simulate a disk-full scenario. The FolderManager constructor might fail for different reasons (directory doesn't exist vs. disk full), leading to different error paths. Consider creating actual directories and simulating disk-full conditions more accurately, or update the test name and comments to reflect what is actually being tested.

        new TSDataType[] {

iotdb-core/datanode/src/test/java/org/apache/iotdb/db/storageengine/dataregion/wal/allocation/FirstCreateStrategyTest.java:271

• The assertion checks if fakeNode.toString() contains "DiskSpaceInsufficientException" or "Failed to create WAL node", but WALFakeNode does not override toString(). This will use the default Object.toString() which returns the class name and hashcode, never matching these strings. The assertion will always fail. Consider checking the failure listener's exception message instead, or add a getter method to WALFakeNode to expose the failure cause.
  iotdb-core/datanode/src/test/java/org/apache/iotdb/db/storageengine/dataregion/wal/allocation/FirstCreateStrategyTest.java:270
• Default toString(): WALFakeNode inherits toString() from Object, and so is not suitable for printing.
  iotdb-core/datanode/src/test/java/org/apache/iotdb/db/storageengine/dataregion/wal/allocation/FirstCreateStrategyTest.java:271
• Default toString(): WALFakeNode inherits toString() from Object, and so is not suitable for printing.

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[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

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Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/dataregion/wal/allocation/AbstractNodeAllocationStrategy.java:91

• The createWALNode overload with four parameters is not synchronized, while the other createWALNode method (line 60) is synchronized. This inconsistency could lead to thread safety issues if both methods are called concurrently and access shared state. For consistency and to prevent potential race conditions, consider making this method synchronized as well, or document why synchronization is not needed for this overload.

  protected IWALNode createWALNode(
      String identifier, String folder, long startFileVersion, long startSearchIndex) {
    try {
      return new WALNode(identifier, folder, startFileVersion, startSearchIndex);
    } catch (IOException e) {
      logger.error("Fail to create wal node", e);
      return WALFakeNode.getFailureInstance(e);
    }
  }

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[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[Copilot]

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Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

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