These settings files currently are generated with an initial timestamp
comment line, which is not something we'd want to track in version
control. Fortunately, the contents of these files are entirely
mundane, so there should be no problem with having Buildship generate
them anew each time a developer imports WALA into Eclipse as an
existing Gradle project.
Apparently Buildship generates these when one uses Import -> Existing
Gradle Project:
<https://discuss.gradle.org/t/buildship-eclipse-plug-in-multiproject-builds/24030/5>.
We can use the Gradle "eclipse" plugin if customizations are
necessary, but my impression is that the intent is to treat ".project"
and ".classpath" as generated files, not sources to be tracked in
source control.
I was confused about the differences among:
srcDir 'foo'
srcDirs ['foo']
srcDirs = ['foo']
As it turns out, the first two append to the set of source
directories, while the last replaces this set entirely. I generally
want replacement, since WALA's current directory layout never matches
Gradle's assumed defaults.
Eclipse's automated code clean-up tool did most of the heavy lifting
here: it specifically has a clean-up option for converting functional
interfaces to lambdas. I merely had to revert the automated changes
for a single enumeration class for which it produced invalid results,
and for a few test inputs that apparently aren't set up to be compiled
with Java 8.
E-mail exchanged with Julian Dolby suggests that this is the right
thing to do, and that it should have been done back when we converted
other parts of the build configuration to Java 8.
These two modules refer to "AST.JLS8". If you have Java 9 installed,
then "AST.JLS8" is marked as deprecated, and we can a warning unless
we suppress or disable the deprecation warning wherever "AST.JLS8" is
used. However, if you don't have Java 9 installed, then "AST.JLS8" is
not deprecated, and trying to suppress deprecation warnings where
"AST.JLS8" is used instead produces warnings about unnecessary warning
suppression. Aagh! Turning off the deprecation warnings entirely for
these two modules seems like the only sane compromise.
Near as I can tell, the requests for deprecated versions here are
intentional. The non-deprecated version (AST.JLS9) is the latest and
greatest, but as far as I can tell we really do want the older version
here.
This is similar to 6caecce3e7, though in
that case JLS8 was the non-reprecated latest version and we were still
asking for JLS3.
These are all problems that Eclipse can detect, but that it detects no
instances of right now. Treating these as warnings instead of errors
should help prevent us from slipping backward in the future.
In particular, per the corresponding Eclipse warning, "The
`javacProjectSettings` build entry should be set when there are
project specific compiler settings".
One such annotation was unnecessary because the thing it was
suppressing no longer happens. Any future unnecessary warning
suppressions of this kind will now be treated as errors.
The other annotations were unnecessary because the corresponding
warnings have been disabled entirely in the Eclipse projects'
configurations. There seems to be no way to tell Eclipse to treat
these as anything other than "info" diagnostics in the future, so
that's how they will remain.
In general, my approach was to try to eliminate each unused parameter
using Eclipse's "Change Method Signature" refactoring. That did not
always succeed: a parameter may be unused in some base class method,
but then be used in subclass's override of that method. In cases
where refactoring to eliminate a parameter failed, I instead annotated
the parameter with '@SuppressWarnings("unused")' to silence the
warning.
Note: this group of changes creates a significant risk of
incompatibility for third-party WALA code. Some removed parameters
change externally-visible APIs. Furthermore, these changes do not
necessarily lead to Java compilation errors. For example, suppose
third-party code subclasses a WALA class or interface, overrides a
method, but does not annotate that method as @Override. Removing a
parameter means that the third-party method no longer overrides. This
can quietly change code behavior without compile-time errors or
warnings. This is exactly why one should use @Override wherever
possible, but we cannot guarantee that third-party WALA users have
done that.
Unnecessary "throws" declarations tend to cascade. If foo() calls
bar() and bar() falsely declares that it might throw IOException, that
often leads a programmer to declare that foo() might throw IOException
as well. Fixing the bar() throws declaration then reveals that we can
fix the foo() throws declaration too. By the time we reach a fixed
point with cleaning these up, we have removed roughly 320 unnecessary
throws declarations.
In a few cases, this cleanup even lets us remove entire "try
... catch" statements where the only thing being caught was an
exception that we now statically know cannot be thrown. Nice!
In Eclipse project configurations, upgrade any future such shenanigans
from warnings to errors. Now that we've fixed this, we don't want it
coming back again.
There is a potential drawback to this change. Conceivably some public
WALA API entry point might have declared that it could throw some
exception merely to reserve the *option* of throwing that exception in
third-party code that subclasses and overrides the API entry point in
question. I have no idea whether this is a significant concern in
practice, though.
Previously we had 227 such warnings. That large number suggests that
the WALA developers consider this to be an acceptable coding style.
If that's so, then it's better to hide these warnings rather than keep
them around as a perpetual distraction.
Previously we had 242 such warnings. That large number suggests that
the WALA developers consider this to be an acceptable coding style.
If that's so, then it's better to hide these warnings rather than keep
them around as a perpetual distraction.
There are two such diagnostics: one for collection methods and one for
equals(). See
<https://www.eclipse.org/eclipse/news/4.7/jdt.php#unlikely-argument-types>
for more information about these two new diagnostics.
For each of these diagnostics, I've set the severity level to
"warning" in projects that have some instances of the suspicious code,
or to "error" in projects that have no instances of the suspicious
code.
Generally, overriding one means you should be overriding the other
too.
Also, configure Eclipse to treat any similar cases as errors, rather
than merely warnings.
These should mostly be things that we've already decided earlier that
we explicitly don't want to "fix" because they simply disagree with
the WALA project's coding style.
The additional diagnostics are ones that were previously being
ignored, but which we seem to have been ignoring by default rather
than as a conscious choice.
For diagnostics of which we currently have *zero* instances, treat
these as errors rather than merely warnings. The intent is to
permanently lock out future regressions of things we've completely
fixed. In the future, whenever we fix the last instance of a given
warning in a given Eclipse project, we should also promote that
diagnostic to an error to keep things clean into the future.
