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https://issues.apache.org/jira/browse/IO-808?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17763886#comment-17763886
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Phil D commented on IO-808:
---------------------------
I'm against that because of my reasons above as well as the following:
The existing javadoc (
https://github.com/apache/commons-io/blob/master/src/main/java/org/apache/commons/io/FileUtils.java#L2387
) states:
{code:java}
/** ...
* @throws FileNotFoundException if the source file does not exist.
* @throws IOException if source or destination is invalid.
... */
{code}
If throws documentation is added for IllegalArgumentException - what would it
be to be API compatible.. something like "throws IllegalArgumentException if a
race condition occurs where the file on the file system was removed during the
execution of this function" I guess too bad if you were expecting
IOException???
I think this is part of a larger problem with the 2.0 implementation where a
lot of race conditions exist due to checking File.exists() and File.isFile().
Only File.isFile() needs to be called. Per the javadoc:
https://docs.oracle.com/javase/8/docs/api/java/io/File.html#isFile--
{code:java}
Returns:
true if and only if the file denoted by this abstract pathname exists and is a
normal file; false otherwise
{code}
Calling File.exists() and then File.isFile() is not only inefficient, its
causing race conditions and indeterminate behavior. Looking at the source
code, this is prevalent. For example any function that calls
requileFileIfExists() has this race condition:
{code:java}
private static File requireFileIfExists(final File file, final String name)
{
Objects.requireNonNull(file, name);
return file.exists() ? requireFile(file, name) : file; // race
condition
}
{code}
> FileUtils.moveFile, copyFile and others can throw undocumened
> IllegalArgumentException
> --------------------------------------------------------------------------------------
>
> Key: IO-808
> URL: https://issues.apache.org/jira/browse/IO-808
> Project: Commons IO
> Issue Type: Bug
> Components: Utilities
> Affects Versions: 2.12.0
> Environment: Windows 10
> Reporter: Phil D
> Priority: Major
> Attachments: MakyAckyBreaky.java, TestMoveFileIAE.java
>
>
> Several of the functions in FileUtils are throwing undocumented
> IllegalArgumentException such as moveFile, copyFile and other locations.
> If the desire is to maintain backwards compatibility with the 1.4 branch for
> these functions, then the 2.12 (and 2.13) versions are throwing
> IllegalArgumentException in cases where 1.4 is not. In fact, it seems like
> 1.4 was coded to specifically avoid IllegalArgumentException and throws
> IOExceptions instead.
> There are several different cases where this is possible. In the most basic,
> I've attached TestMoveFileIAE, where this can be reproduced by simple running:
> {code:bash}
> mkdir one
> java -cp <your_classpath> TestMoveFileIAE one two
> Exception in thread "main" java.lang.IllegalArgumentException: Parameter
> 'srcFile' is not a file: one
> at org.apache.commons.io.FileUtils.requireFile(FileUtils.java:2824)
> at org.apache.commons.io.FileUtils.moveFile(FileUtils.java:2395)
> at org.apache.commons.io.FileUtils.moveFile(FileUtils.java:2374)
> at TestMoveFileIAE.main(TestMoveFileIAE.java:13)
> {code}
> In a less likely scenario (which is how I found this issue because this
> happened on a production system); If the srcFile is removed at a certain
> point during moveFile() execution then IllegalArgumentException is throws:
> https://github.com/apache/commons-io/blob/master/src/main/java/org/apache/commons/io/FileUtils.java#L2392
> {code:java}
> 2392 public static void moveFile(final File srcFile, final File destFile,
> final CopyOption... copyOptions) throws IOException {
> 2393 validateMoveParameters(srcFile, destFile); // checks srcFile.exists()
> /// ==== srcFile deleted here!!!
> 2394 requireFile(srcFile, "srcFile"); // checks srcFile.isFile()
> and throws IAE
> 2395 requireAbsent(destFile, "destFile");
> /// ==== srcFile could also be deleted here
> 2396 ... // renameTo or copyFile() which also calls requireCopyFile() and
> requireFile()
> {code}
> This pattern of calling validateMoveParameters() and requireFile() will throw
> IllegalArgumentException every when the srcFile is removed between between
> validateMoveParameters() and requireFile() or requireFileCopy() and
> requireFile()
> Preferably, it would be best if the 2.x versions of FileUtils were backwards
> compatible with 1.x and IllegalArgumentException would not be thrown, but
> IOException (or one of its derivatives) would be. IAE is an unchecked
> exception and can cause unexpected issues.
> I would also suggest that unit tests be created to ensure that these
> functions behave as expected in error conditions.
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