The "potentially" qualifier is here because these methods are visible
outside the WALA source tree. These methods may seem OK to be static
based on the code we have here, but we have no way of knowing whether
third-party code expected to be able to subclass and override. I'm
going to play it safe and assume that we want to allow that.
Note that we are still allowing Eclipse warnings about methods that
can *definitely* be declared static; a different configuration option
controls these. For private methods, final methods, and methods in
final classes, if the code seems static-safe based on what we have
here, then that's good enough: we don't need to worry about
third-party overrides.
Specifically, these are all warnings of the form "The
'javacProjectSettings' build entry should be set when there are project
specific compiler settings".
Specifically, we're turning off Eclipse warnings about missing version
constraints on required bundles ("Require-Bundle"), exported
packages ("Export-Package"), and imported packages ("Import-Package").
We're not turning these off absolutely everywhere, though: only in
packages where one or more such warnings were actually being reported.
So if a given package was already providing all version constraints
for, say, package imports, then we've kept that warning on in that
package.
Honestly I don't entirely understand the practical implications of
these warnings. However, there were 355 of them across many WALA
subprojects. I take this as evidence that the WALA developers do not
consider these version constraints to be important. Therefore, we may
as well stop warning about something we have no intention of fixing.
That being said, if we *do* want to fix some or all of these, I
welcome any advice on what those fixes should look like. I am rather
ignorant about all things OSGi.
Manu requested that we use this approach instead of adding
`@SuppressWarnings("unused")` at each affected catch block. That
seems reasonable to me, given the large number of such warnings and
the lack of likely harm from ignoring such caught exceptions.
This should make it easier for newcomers to get WALA up and running
from sources. One no longer needs to manually find "dx.jar" using
instructions given at
<http://wala.sourceforge.net/wiki/index.php/UserGuide:Getting_Started#Building_the_code>
or
<https://groups.google.com/forum/#!msg/wala-sourceforge-net/cBYsfEvYVG0/Ua52dyQQU-YJ>.
Those instructions were already out-of-date, anyway.
Given that an official release of "dx.jar" is available in Maven, it
would be nice to have Maven itself manage that dependency.
Unfortunately, it seems that WALA in general does not use Maven for
dependency management. As far as I can tell, the Maven configuration
just calls out to Ant for doing builds, including having Ant download
other needed components. If WALA ever moved to using Maven more
fully, downloading "dx.jar" could easily come along with that.
This fixes 33 out of 37 Eclipse "Potential resource leak: '...' may
not be closed" warnings. It also fixes 3 out of 37 Eclipse "Resource
'...' should be managed by try-with-resource" warnings, although that
was not the main focus of this effort.
The remaining 4 warnings about potential resource leaks all involve a
leaked JarFile instance that is passed to a JarFileModule constructor
call. JarFileModile never attempts to close its underlying JarFile;
this code is written as though JarFile cleanup were the caller's
responsibility. However, the JarFile often cannot be closed by the
code that creates the JarFileModule either, since the JarFile needs to
remain open while the JarFileModule is in use, and some of these
JarFileModules stay around beyond the lifetime of the code that
created them. Truly fixing this would essentially require making
JarFileModule implement Closeable, which in turn would probably
require that Module implement Closeable, which in turn would require
changes to lots of code that deals with Module instances to arrange
for them to be properly closed. That's more invasive than I'm
prepared to take on right now.
Instead, rely on Java's ability to infer type parameters in many
contexts. This removes 665 Eclipse warnings.
Note: a few of these changes are to files under "test" subdirectories.
Presumably those are files that serve as test inputs rather than being
part of WALA code proper. As far as I can tell, these changes do not
break any WALA tests. But if any of those tests were specifically
intended to exercise WALA on code with non-inferred generic type
parameters, then I really should be leaving those alone.
Previously, the various Eclipse projects' Java configurations used
mixtures of 1.6, 1.7, and 1.8. Many were internally inconsistent,
such as requiring 1.7 in "MANIFEST.MF" but 1.6 in the Eclipse JDT
build preferences. The Travis-CI configuration tests against both 1.7
and 1.8, but does not test against 1.6.
Across all projects, the most common version was 1.7. So I'm going to
assume that 1.7 is the intended build target. This commit makes 1.7
the selected version nearly everywhere.
"com.ibm.wala.core.testdata" is the one exception. This specific
project uses a few features only found in 1.8, such as lambda
expressions. Previously, "com.ibm.wala.core.testdata" used 1.7 in
some aspects of its configuration but 1.8 in others. Now it
consistently targets 1.8. I wish this one project didn't need to be
inconsistent with the rest of WALA, but at least now it's consistent
with itself.
(Personally, I'd be happy to target 1.8 only. But my impression
across all of these configuration files is that the WALA developers
still want to be compatible with 1.7. If that is no longer a
requirement, let me know and I will adjust these changes accordingly
to target 1.8 only.)
This change eliminates 11 "There is no 'jre.compilation.profile' build
entry and the project has Java compliance preferences set" warnings
and 13 "The JRE container on the classpath is not a perfect match to
the 'JavaSE-1.7' execution environment" warnings. However, it also
adds 450 "Redundant specification of type arguments <...>" warnings
and 17 "Resource '...' should be managed by try-with-resource"
warnings. So this seems like a net step backward in my wish to reduce
WALA warnings. However, those new warnings concern Java 1.7 language
features that we were not previously using to good effect in projects
that targeted 1.6. If we all agree that we can now target 1.7
instead, then we can use these helpful features as the newly-added
warnings suggest. So I call that a step in the right direction.
When Maven generates these "*/target/antrun/build-main.xml" Any build
scripts, it does not include any DTD or XML Schema declarations.
Eclipse's XML validator warns about the lack of grammar constraints.
The warning is sensible, but we are not in a position to do anything
about it. Better, therefore, to suppress these warnings so that we
can more-clearly see warnings we *can* address.
I think the "target/p2artifacts.xml" and "target/p2content.xml" files
are generated by Maven. They are well-formed XML but Eclipse's XML
validator legitimately warns that they lack grammar constraints.
Since we're not maintaining the tool that creates these files, we are
not in a position to do anything about that. Therefore, we may as
well exclude these from validation entirely. That way we can
more-clearly recognize warnings that we *can* do something about.
Ant "build.xml" files don't have a standard DTD or XML Schema; the
contents are simply too flexible for that. But we can at least
give each a stub DOCTYPE declaration. That's enough to satisfy
Eclipse's XML validator, which otherwise complains that these files
lack grammar constraints.
As created by Tycho Surefire, these files are XML documents without
DTD or XML Schema declarations. The XML validator warns about this
omission. However, Surefire is not a WALA component. We are not in a
suitable position to change it to include XML schema or DTD
declarations in the XML files it generates. Better, then, to ignore
this benign problem so we can focus on warnings that we can act on
directly.
Eclipse validation warns about invalid HTML content in all
Maven-generated "target/site/dependency-convergence.html" files. The
warnings are legitimate: these HTML files are indeed invalid.
However, we don't maintain the tool that generates these files, so we
are not in a position to fix them. Better, therefore, to suppress
these warnings so that we can notice and fix other problems over which
we do have control.
In general, the WALA code base is not really ready for nullness
checking. It would be nice if we got there some day, but I'm not
planning to take that on now or any time soon. Until then, it's not
useful to warn about missing @NonNullByDefault declarations on WALA
packages.
See also older commit 7b6811b.
Ben Liblit
Manu Sridharan
Julian Dolby
Michael Herzberg
Julian Dolby
Manu Sridharan