[Chore][Common] Handle parentless paths in FileUtils

[hiSandog]

Was this PR generated or assisted by AI?

YES. The implementation and regression test were assisted by Codex.

Purpose of the pull request

FileUtils.writeContent2File dereferences getParentFile() unconditionally. A valid relative filename such as output.txt has no parent component, so the method throws a NullPointerException instead of writing the file.

Brief change log

• Guard parent-directory creation when the destination has no parent component.
• Add a regression test that writes and cleans up a parentless relative path.

Verify this pull request

This change added tests and was verified as follows:

• ./mvnw -q -pl dolphinscheduler-common -Dlombok.version=1.18.36 -Dspotless.skip=true -Dtest=FileUtilsTest test (9 tests passed; overrides only adapt the local JDK 21 environment)
• ./mvnw -q -pl dolphinscheduler-common -Dspotless.version=2.44.3 -DspotlessFiles='src/main/java/org/apache/dolphinscheduler/common/utils/FileUtils.java,src/test/java/org/apache/dolphinscheduler/common/utils/FileUtilsTest.java' spotless:check
• git diff --check upstream/dev...HEAD

Pull Request Notice

Pull Request Notice