[commons-compress] branch master updated: Avoid NPE in FileNameUtils.getExtension(Path) for paths with zero elements like root paths

[ggregory]

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ggregory pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/commons-compress.git


The following commit(s) were added to refs/heads/master by this push:
     new 2acca516 Avoid NPE in FileNameUtils.getExtension(Path) for paths with 
zero elements like root paths
2acca516 is described below

commit 2acca51656334254dcfac8f33d6d476464e93ea7
Author: Gary Gregory <garydgreg...@gmail.com>
AuthorDate: Wed Nov 30 06:39:42 2022 -0500

    Avoid NPE in FileNameUtils.getExtension(Path) for paths with zero
    elements like root paths
---
 src/changes/changes.xml                                           | 1 +
 .../java/org/apache/commons/compress/utils/FileNameUtils.java     | 3 ++-
 .../java/org/apache/commons/compress/utils/FileNameUtilsTest.java | 8 ++++++++
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/changes/changes.xml b/src/changes/changes.xml
index 107d5305..c43b4cb1 100644
--- a/src/changes/changes.xml
+++ b/src/changes/changes.xml
@@ -46,6 +46,7 @@ The <action> type attribute can be add,update,fix,remove.
       <!-- FIX -->
       <action type="update" dev="ggregory" due-to="CodeQL, Gary 
Gregory">Implicit narrowing conversion in compound assignment.</action>
       <action type="update" dev="ggregory" due-to="CodeQL, Gary Gregory">Avoid 
NPE in FileNameUtils.getBaseName(Path) for paths with zero elements like root 
paths.</action>
+      <action type="update" dev="ggregory" due-to="CodeQL, Gary Gregory">Avoid 
NPE in FileNameUtils.getExtension(Path) for paths with zero elements like root 
paths.</action>
       <!-- ADD -->
       <!-- UPDATE -->
       <action type="update" dev="ggregory" due-to="Dependabot">Bump 
mockito.version from 4.8.0 to 4.9.0 #328, #331.</action>
diff --git a/src/main/java/org/apache/commons/compress/utils/FileNameUtils.java 
b/src/main/java/org/apache/commons/compress/utils/FileNameUtils.java
index c6738137..323607fc 100644
--- a/src/main/java/org/apache/commons/compress/utils/FileNameUtils.java
+++ b/src/main/java/org/apache/commons/compress/utils/FileNameUtils.java
@@ -87,7 +87,8 @@ public class FileNameUtils {
         if (path == null) {
             return null;
         }
-        return fileNameToExtension(path.getFileName().toString());
+        final Path fileName = path.getFileName();
+        return fileName != null ? fileNameToExtension(fileName.toString()) : 
null;
     }
 
     /**
diff --git 
a/src/test/java/org/apache/commons/compress/utils/FileNameUtilsTest.java 
b/src/test/java/org/apache/commons/compress/utils/FileNameUtilsTest.java
index b0edcc3a..328918cc 100644
--- a/src/test/java/org/apache/commons/compress/utils/FileNameUtilsTest.java
+++ b/src/test/java/org/apache/commons/compress/utils/FileNameUtilsTest.java
@@ -74,6 +74,14 @@ public class FileNameUtilsTest {
     public void getExtensionPathBaseCases() {
         assertEquals("foo", 
FileNameUtils.getExtension(Paths.get("a/b/c/bar.foo")));
         assertEquals("", FileNameUtils.getExtension(Paths.get("foo")));
+        assertEquals("", FileNameUtils.getExtension(Paths.get("")));
+        assertEquals("", FileNameUtils.getExtension(Paths.get(".")));
+        for (File f : File.listRoots()) {
+            assertEquals(null, FileNameUtils.getExtension(f.toPath()));
+        }
+        if (SystemUtils.IS_OS_WINDOWS) {
+            assertEquals(null, FileNameUtils.getExtension(Paths.get("C:\\")));
+        }
     }
 
     @Test