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.
Previously each of these `switch` statements would implicitly do
nothing if an unanticipated `enum` value came along. My impression is
that each of these `switch` statements is supposed to be exhaustive,
such that an unexpected (unhandled) value should never appear. If one
does, we should recognize it and complain loudly.
Of course, sometimes the right behavior for previously-unhandled
values is to do nothing. It may not always be clear whether an
exception or doing nothing is the right choice. For this commit,
WALA's regression tests still pass even with the possibility of
throwing an exception for unexpected values. If we assume that the
test suite is thorough, that tells me that throwing an exception is
the right policy for each `switch` statement that I'm changing here.
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 5 such warnings. That's not very many, but it
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 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.
In general, these diagnostics are now errors in projects for which all
such warnings have been fixed. There are three unfixed warnings in
two projects, so this diagnostic remains a warning (not an error) in
those projects.
There are also many places where rwa-types-usage warnings have been
locally suppressed using @SuppressWarnings annotations. I haven't
systematically revisited those to see if any can be fixed properly.
So for those projects this diagnostic must also remain a warning (not
an error), since @SuppressWarnings does not work on things Eclipse is
configured to treat as errors.
Along the way, I also converted many "for (;;)" loops into modern
"for (:)" loops. I didn't systematically look for all opportunities
to do this, though. I merely made this change where I was already
converting raw Iterator uses into modern Iterator<...> uses.
Better use of generics also allowed many casts to become statically
redundant. I have removed all such redundant casts.
Only three raw-types warnings remain after this batch of fixes. All
three involve raw uses of CallGraphBuilder. I've tried to fix these
too, but it quickly snowballs into a cascade of changes that may or
may not eventually reach a statically-type-save fixed point. I may
give these last few problem areas another go in the future. For now,
though, the hundreds of other fixes seem worth keeping even if there
are a few stragglers.
This commit may change some public APIs, but only by making weaker
type signatures stronger by replacing raw types with generic types.
For example, we may change something like "Set" into "Set<String>",
but we're not adding new arguments, changing any
underlying (post-generics-erasure) types, etc.
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.
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.
If a method is private, there's no risk that a subclass elsewhere
might be overriding it and depending on dynamic dispatch to choose the
right implementation. So all of these private methods can safely be
declared static without risk of regression in either WALA code or
unseen third-party code.
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.
These changes turn off Eclipse warnings for Javadoc tags without
descriptions. In some subprojects, we turn these off entirely. In
others, leave on missing-descrption checks for "@return" tags only.
We don't turn this warning off in all projects. Rather, we turn it
off only in projects that were producing at least one such warning.
In other words, if a project was already completely "clean" with
respect to this warning, then we leave this warning enabled for that
project.
Turning off these warnings is a partial declaration of Javadoc
bankruptcy. In an ideal world, we would enable and fix all of these
warnings. However, there are 576 of them. Apparently the WALA team's
implicit coding style says that omitting descriptions is OK. If
there's no intent to systematically add descriptions, then we may as
well turn off these warnings so that we can see other warnings that we
may want to fix.
In the cases addressed here, the caught exception was being "handled"
by throwing some new exception. Instead of discarding the old
exception, pass it to the new exception's constructor to indicate the
original cause of the newly-created exception. This practice, called
"exception chaining", can often be useful in debugging.
Near as I can tell, the request for a deprecated version here is
intentional. The non-deprecated version (AST.JLS8) is the latest and
greatest, but as far as I can tell we really do want the older version
here.
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.
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.
Ben Liblit
Julian Dolby
Manu Sridharan
Manu Sridharan