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.
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.
* Fixed bug for source analysis
Do while in case statement would throw an NPE. Now it doesn't
* Added test case
The test will fail with an NPE if the fix is not applied.
* Fix warnings about unset javacProjectSettings build entries
Specifically, these are all warnings of the form "The
'javacProjectSettings' build entry should be set when there are project
specific compiler settings".
* Add @Override annotations to all methods that do override
This fixes 287 Eclipse code style warnings.
* Cannot add @Override annotations here, so suppress warnings instead
We should be able to add these @Override annotations in the future,
one Eclipse Mars and earlier are no longer supported. For now,
though, they have to go away in order to be compatible with older
Eclipse releases.
* Fix warnings about unset javacProjectSettings build entries
Specifically, these are all warnings of the form "The
'javacProjectSettings' build entry should be set when there are project
specific compiler settings".
* Turn off Eclipse warnings about undocumented empty blocks
The presence of 65 such warnings in two packages suggests that the de
facto WALA coding style does not mandate documenting empty blocks.
Better to avoid printing warnings that will be routinely ignored, so
that other important warnings are more likely to be noticed.
* Turn off Eclipse warnings about synthetic accessor methods
Synthetic accessor methods allow access to otherwise inaccessible
members of enclosing types. The presence of 246 such warnings in
three packages suggests that the de facto WALA coding style does not
consider synthetic accessor methods to be problematic. Better to
avoid printing warnings that will be routinely ignored, so that other
important warnings are more likely to be noticed.
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.
Along with these fixes, convert several for loops that used explicit
iterators into newer-style for-each loops that hide the iterators and
casts inside the syntactic sugar. Nice!
However, I have not systematically tried to modernize *all* for loops
that could instead be for-each loops. Someone could certainly do that
at some point. In this commit, I only converted loops that I had to
touch anyway because they were using raw "Iterator" types.
Removing an unused field sometimes means removing constructor code
that used to initialize that field. Removing that initialization code
sometimes leaves whole constructor arguments unused. Removing those
unused arguments can leave us with unused code to compute those
arguments in constructors' callers, and so on. This commit tries to
clean all of this up, working backward from the unused fields that an
earlier commit already removed. Hopefully I have avoided removing
upstream code that had other important side effects, but it wouldn't
hurt for a WALA expert to review this change carefully.
If the true block of an `if` statement is guaranteed to exit early,
such as by a `return` or `throw`, then any code appearing in a
corresponding `else` clause could just as well have appeared after the
`if` statement entirely. Eclipse can warn about this.
However, Manu prefers to let such code stay in the `else` clauses.
OK, sure: this is more a matter of personal taste than something truly
problematic. Per Manu's request, then, we're turning off that Eclipse
warning in the subprojects in which it currently arises.
These changes turn off Eclipse warnings for Javadoc comments with
missing tags, such as "@throw" or "@param".
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 327 of them. Apparently the WALA team's
implicit coding style says that omitting Javadoc tags is OK. If
there's no intent to systematically add these tags, then we may as
well turn off these warnings so that we can see other warnings that we
may want to fix.
These changes turn off Eclipse warnings for documentable items without
Javadoc comments. In some subprojects, we turn these off entirely.
In others, we leave these warnings on for public items but not for
items whose visibility is protected or below.
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 1,366 of them. Apparently the WALA
team's implicit coding style says that omitting Javadoc comments is
OK. If there's no intent to systematically add documentation, then we
may as well turn off these warnings so that we can see other warnings
that we may want to fix.
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.
Specifically, these warnings are always of the form "Statement
unnecessarily nested within else clause. The corresponding then clause
does not complete normally". I can see this being a matter of
personal taste, actually. If the WALA maintainers decide that they
prefer to keep this code as it was before, that's OK with me: I'll
replace this group of code changes with a group of settings changes
that tell Eclipse to quietly ignore this "problem".
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.
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.
This interface method was added in Eclipse Neon, so we need to implement
it here to have a non-abstract class. With this fix, WALA now builds
with no errors inside Eclipse Neon. (There are still a few thousand
warnings, but that's nothing new.)
The new project only depends on the minimal Eclipse plugins to make the
ECJ frontend work. Hence, it should be amenable to creating a Maven
Central jar.
Ben Liblit
Julian Dolby
Caius Brindescu
Manu Sridharan
Julian Dolby
Julian Dolby
Manu Sridharan