FSInfo#getJarClassPath does not comply with the JAR specification

[David Lloyd]

How would you account for JDK-8216401 in this case?  Would you say
that the specification should have been updated to account for the
implementation?

On Thu, Oct 17, 2019 at 9:34 AM Jonathan Gibbons
<jonathan.gibbons at oracle.com> wrote:
>
> Any changes/exceptions should be done in conjunction with updates to
> specification.
>
> -- Jon
>
> On 10/17/19 6:04 AM, David Lloyd wrote:
> > It seems reasonable to include the special exception for `file:` absolute URLs.
> >
> > I did file a bug at bugreport but I haven't yet received a
> > notification that the bug was created. If I do, I will post the JIRA #
> > here.
> >
> > On Wed, Oct 16, 2019 at 9:33 PM Jaikiran Pai <jai.forums2013 at gmail.com> wrote:
> >> One of the reasonsI hadn't done anything related to this in my proposed
> >> change to FSInfo#getJarClassPath patch[1] was because I wasn't sure what
> >> the actual expected semantics of the Class-Path attribute are.
> >>
> >> The jar Manifest documentation (which David pointed to) does state the
> >> URI is to be relative, but I remember seeing a recent change discussed
> >> in one of these mailing lists where absolute (file: scheme based) URIs
> >> were supported. I finally found time to look through the JBS and here's
> >> that issue https://bugs.openjdk.java.net/browse/JDK-8216401. So I think
> >> whatever change we do here will then have to allow for absolute URI (for
> >> file: scheme of local jars too).
> >>
> >> [1]
> >> http://mail.openjdk.java.net/pipermail/compiler-dev/2019-October/013760.html
> >>
> >> -Jaikiran
> >>
> >> On 14/10/19 10:13 PM, David Lloyd wrote:
> >>> The JAR specification specifies that the `Class-Path` attribute is a
> >>> space-separated sequence of relative URLs.  A relative URL is defined
> >>> ([2], [3]) as a hierarchical URI with no scheme component.
> >>>
> >>> Relative URLs resemble file paths.  However they differ in some
> >>> important ways: for example, a relative URL is URL-encoded, whereas a
> >>> file path is not, causing problems when dealing with paths that have
> >>> embedded spaces (among other things).  Relative URLs representing
> >>> absolute paths on Windows have a form like `/C:/Foo/Bar`, whereas the
> >>> corresponding file path would be `C:/Foo/Bar` or `C:\Foo\Bar`.
> >>>
> >>> Note (since this is a point of frequent confusion) that a relative URL
> >>> can have an absolute path.
> >>>
> >>> AFAIK neither of these cases work correctly when javac interacts with
> >>> a JAR that contains a `Class-Path` attribute.
> >>>
> >>> The current FSInfo code, as noted in the recent thread entitled
> >>> `FSInfo#getJarClassPath throws an exception not declared in its throws
> >>> clause`, reads the class path attribute value with code that uses
> >>> FileSystems.getDefault().getPath(xxx) on each class path element [4].
> >>>
> >>> The correct behavior would be to wrap each item in a `java.net.URI`.
> >>> If the syntax is invalid, report an error or skip the element.  Then
> >>> determine if the URI is absolute; if it is, report an error or skip
> >>> the element.  Finally, query the Path API to look up the file by URI
> >>> using Path.of(uri) or similar, reporting an error or skipping the
> >>> element if there's a problem.
> >>>
> >>> The less-elegant solution would be to manually URL-decode the string,
> >>> and (on windows) manually check to see if there's a drive letter,
> >>> removing the leading slash if there is one.  However I would consider
> >>> this to be more likely to be bug-prone.
> >>>
> >>> This problem is the underlying cause of at least one Quarkus bug [5],
> >>> where the issue was discussed in depth.
> >>>
> >>> [1] https://docs.oracle.com/javase/10/docs/specs/jar/jar.html#class-path-attribute
> >>> [2] RFC 3986 § 4.2 - https://tools.ietf.org/html/rfc3986#section-4.2
> >>> [3] https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/net/URI.html
> >>> [4] https://github.com/openjdk/jdk/blob/4ad3d82c76936a8927ed8a505689a3683144ad98/src/jdk.compiler/share/classes/com/sun/tools/javac/file/FSInfo.java#L112
> >>> [5] https://github.com/quarkusio/quarkus/issues/3592
> >>>
> >



-- 
- DML