diff --git a/WHATSNEW b/WHATSNEW
index 342095898..d91c47676 100644
--- a/WHATSNEW
+++ b/WHATSNEW
@@ -10,6 +10,11 @@ Changes that could break older environments:
  * The <apt> task has been removed since apt itself has been removed
    with Java8.
 
+ * <fileset>/<zipfileset>/<tarfileset> exhibited undefined
+   behavior when both the dir and file attribute have been used on the
+   same instance. This will now cause the build to fail.
+   Bugzilla Report 59402
+
 Fixed bugs:
 -----------
 
diff --git a/manual/Types/fileset.html b/manual/Types/fileset.html
index 9a7c7d716..3d901723a 100644
--- a/manual/Types/fileset.html
+++ b/manual/Types/fileset.html
@@ -50,7 +50,7 @@ equivalent to an <code>&lt;and&gt;</code> selector container.</p>
   <tr>
     <td valign="top">dir</td>
     <td valign="top">the root of the directory tree of this FileSet.</td>
-    <td valign="middle" align="center" rowspan="2">Either dir or file must be specified</td>
+    <td valign="middle" align="center" rowspan="2">Exactly one of dir or file must be specified</td>
   </tr>
   <tr>
     <td valign="top">file</td>
diff --git a/src/main/org/apache/tools/ant/taskdefs/AbstractJarSignerTask.java b/src/main/org/apache/tools/ant/taskdefs/AbstractJarSignerTask.java
index bc8c03195..c93173b34 100644
--- a/src/main/org/apache/tools/ant/taskdefs/AbstractJarSignerTask.java
+++ b/src/main/org/apache/tools/ant/taskdefs/AbstractJarSignerTask.java
@@ -382,7 +382,6 @@ public abstract class AbstractJarSignerTask extends Task {
             FileSet sourceJar = new FileSet();
             sourceJar.setProject(getProject());
             sourceJar.setFile(jar);
-            sourceJar.setDir(jar.getParentFile());
             sources.add(sourceJar);
         }
         return sources;
diff --git a/src/main/org/apache/tools/ant/types/AbstractFileSet.java b/src/main/org/apache/tools/ant/types/AbstractFileSet.java
index bc3d02ef9..92d5ace9c 100644
--- a/src/main/org/apache/tools/ant/types/AbstractFileSet.java
+++ b/src/main/org/apache/tools/ant/types/AbstractFileSet.java
@@ -70,6 +70,7 @@ public abstract class AbstractFileSet extends DataType
     private List<FileSelector> selectors = new ArrayList<FileSelector>();
 
     private File dir;
+    private boolean fileAttributeUsed;
     private boolean useDefaultExcludes = true;
     private boolean caseSensitive = true;
     private boolean followSymlinks = true;
@@ -134,6 +135,9 @@ public abstract class AbstractFileSet extends DataType
         if (isReference()) {
             throw tooManyAttributes();
         }
+        if (fileAttributeUsed && !getDir().equals(dir)) {
+            throw dirAndFileAreMutuallyExclusive();
+        }
         this.dir = dir;
         directoryScanner = null;
     }
@@ -231,7 +235,11 @@ public abstract class AbstractFileSet extends DataType
         if (isReference()) {
             throw tooManyAttributes();
         }
+        if (getDir() != null) {
+            throw dirAndFileAreMutuallyExclusive();
+        }
         setDir(file.getParentFile());
+        fileAttributeUsed = true;
         createInclude().setName(file.getName());
     }
 
@@ -943,4 +951,8 @@ public abstract class AbstractFileSet extends DataType
             setChecked(true);
         }
     }
+
+    private BuildException dirAndFileAreMutuallyExclusive() {
+        return new BuildException("you can only specify one of the dir and file attributes");
+    }
 }
diff --git a/src/tests/antunit/types/fileset-test.xml b/src/tests/antunit/types/fileset-test.xml
index 9580a1cec..ea39dec8b 100644
--- a/src/tests/antunit/types/fileset-test.xml
+++ b/src/tests/antunit/types/fileset-test.xml
@@ -64,4 +64,22 @@
     <au:assertLogContains text="fileset-test.xml"/>
   </target>
 
+  <target name="test-fileset-dir-and-file-exception">
+    <mkdir dir="${output}"/>
+    <au:expectfailure expectedmessage="you can only specify one of the dir and file attributes">
+      <copy todir="${output}">
+        <fileset dir="foo" file="bar" />
+      </copy>
+    </au:expectfailure>
+  </target>
+
+  <target name="test-fileset-file-and-dir-exception">
+    <mkdir dir="${output}"/>
+    <au:expectfailure expectedmessage="you can only specify one of the dir and file attributes">
+      <copy todir="${output}">
+        <fileset file="bar" dir="foo"/>
+      </copy>
+    </au:expectfailure>
+  </target>
+
 </project>