Issue #15484: New check UnusedTryResourceShouldBeUnnamed by kkoutsilis · Pull Request #17075 · checkstyle/checkstyle

kkoutsilis · 2025-05-14T19:58:04Z

Aims to close #15484

Implemented new UnusedTryResourceShouldBeUnnamedCheck, similarly to UnusedCatchParameterShouldBeUnnamedCheck and UnusedLambdaParameterShouldBeUnnamedCheck.

New module config: https://gist.githubusercontent.com/kkoutsilis/899b361c1d74b0088fa76eeb96c34396/raw/7942207355ed3afa9ac23dd382acc0305472f2a4/config.xml

kkoutsilis · 2025-05-30T08:03:31Z

@romani Need to fix the CI, probably add more tests as there are a few mutations, but feel free to have a first look if you have some time.

romani · 2025-05-31T14:09:42Z

Semaphore failure is expected due to new check.
javac21 must be fixed.

romani · 2025-05-31T14:11:42Z

@kkoutsilis , please run diff testing.

kkoutsilis · 2025-06-01T12:19:10Z

GitHub, generate report

romani · 2025-06-01T19:41:59Z

https://github.com/checkstyle/contribution/tree/master/checkstyle-tester#executing-generation-using-github-action

Attention to New module config: {{URI to new_module_config.xml}}
And attention to other merged PRs description, there are bunch of examples

kkoutsilis · 2025-06-02T20:44:23Z

GitHub, generate report

github-actions · 2025-06-02T21:19:44Z

https://checkstyle-diff-reports.s3.us-east-2.amazonaws.com/43f253c_2025211859/reports/diff/index.html

romani · 2025-06-02T21:40:52Z

Looks like false positive https://checkstyle-diff-reports.s3.us-east-2.amazonaws.com/43f253c_2025211859/reports/diff/camunda/index.html#A1

Please review your report your self first, to shorten feedback loop.
Looks like I was to quick to respond to this PR :)

kkoutsilis · 2025-06-03T08:17:39Z

Looks like false positive https://checkstyle-diff-reports.s3.us-east-2.amazonaws.com/43f253c_2025211859/reports/diff/camunda/index.html#A1

Please review your report your self first, to shorten feedback loop. Looks like I was to quick to respond to this PR :)

Hey @romani, why is this a false positive? As far as I can tell ignored is not used in the try body. Am I missing something?

Should we not account for try-resources that are named ignored?

kkoutsilis · 2025-06-03T16:58:17Z

Found a small issue, if there are multiple unused try-resources, only one is logged (ref). Looking into fixing that

romani · 2025-06-03T20:58:00Z

It might be complicated to catch all violations at ones, we usually ok to report closest place only, do not go crazy.

kkoutsilis · 2025-06-03T21:12:11Z

GitHub, generate report

romani · 2025-10-21T04:11:31Z

Best form of acceptance by users of new Check is merged PR.
https://checkstyle-diff-reports.s3.us-east-2.amazonaws.com/f71136d_2025021825/reports/diff/camunda/index.html

You can send PR to them and see how users will react on such updates.

romani

Items

romani · 2025-10-21T04:15:32Z

+
+            try (AutoCloseable b = lock()) { // warn
+
+            } catch (Exception e) {


It will be better to remove extra empty lines.
Compact code input is good

romani · 2025-10-21T04:16:46Z

+ *
+ * <p>
+ * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
+ * </p>


This paragraph and all below should be removed.
There are automatically generated, just put macros in template

romani · 2025-10-21T04:18:00Z

+ *
+ * @since 12.2.0
+ */
+@FileStatefulCheck


If possible, it will be good to make it state less.
It will help a lot during migration to multi threading or checkstyle

Hmm, I might need some help with that, let me see

romani · 2025-10-21T04:19:26Z

-unused.catch.parameter=Käyttämättömän saalisparametrin "{0}" tulee olla nimeämätön.
-unused.lambda.parameter=Käyttämättömän lambda-parametrin "{0}" tulee olla nimeämätön.
+unused.catch.parameter=Käyttämättömän saalisparametrin ''{0}'' tulee olla nimeämätön.
+unused.lambda.parameter=Käyttämättömän lambda-parametrin  ''{0}'' tulee olla nimeämätön.


Please avoid unrelated changes
Move them to separate PR, if this is a typo.

romani · 2025-10-21T13:00:17Z

GitHub, generate report

github-actions · 2025-10-21T13:30:55Z

https://checkstyle-diff-reports.s3.us-east-2.amazonaws.com/f71136d_2025133015/reports/diff/index.html

romani · 2025-10-21T15:26:27Z

GitHub, generate report

github-actions · 2025-10-21T15:55:08Z

https://checkstyle-diff-reports.s3.us-east-2.amazonaws.com/f71136d_2025155428/reports/diff/index.html

kkoutsilis · 2025-10-22T17:49:55Z

@kkoutsilis , please keep copy of all codes that caused exception to your Inputs to not rely much on diff testing. Vast majority should be in our tests.

Ones all exception eliminated, we can start review of violations for validity

Hey @romani, the code was failing when a static var was used in the try resource, and also for some test files like this one. Added this test for it. Do you think more input files are required?

romani · 2025-10-22T22:11:31Z

Yes, if code is compiled, we have to work on it without exceptions.

kkoutsilis · 2025-10-26T20:31:53Z

+    void test3() {
+      Object v2 = new Object();
+      Object v3 = new Object() {
+          public void close() {
+          }
+     };
+
+      // violation below, 'Unused try resource 'v2' should be unnamed'
+      try (v2) {
+          fail("not an AutoCloseable");
+      }
+      // violation below, 'Unused try resource 'v3' should be unnamed'
+      try (v3) {
+          fail("not an AutoCloseable although has close() method");
+      }
+      try (java.lang.Object) {
+          fail("not a variable access");
+      }
+      try (java.lang) {
+          fail("not a variable access");
+      }


@romani Added this from https://github.com/openjdk/jdk21/blob/890adb6410dab4606a4f26a942aed02fb2f55387/test/langtools/tools/javac/TryWithResources/TwrForVariable3.java#L6, which was causing an exception before, but now CI fails. Since this code is not compilable, are you fine to remove?

From where you got this code?
We need to make sure it is compilation good at that project.
For us it is hard limitation - execution only on fully compile-able sources.

If this is not compiled sources, please remove it ,and it ok to have exception on such code in diff report.

Code is from jdk21 tests, link above, got it because it was causing an exception in a previous report here https://checkstyle-diff-reports.s3.us-east-2.amazonaws.com/571223a_2025223753/reports/diff/openjdk21/index.html#A229. Will remove from tests then, thanks

lets pay more attnetion - https://github.com/openjdk/jdk21/blob/master/test/langtools/tools/javac/TryWithResources/TwrForVariable1.java

it looks like compiled, it isnot random crap, and even issue number is referenced.
lets look at it.

it is compiled at https://www.jdoodle.com/online-java-compiler, so lets double focus on why local javac is not happy.

TwrForVariable1 is compiled, but I am pointing to TwrForVariable3, this does not compile for me. My understanding is that this test is expected not to compile looking at TwrForVariable3.out file

https://github.com/openjdk/jdk21/blob/890adb6410dab4606a4f26a942aed02fb2f55387/test/langtools/tools/javac/TryWithResources/TwrForVariable3.java#L4

* @compile/fail/ref=TwrForVariable3.out

This line looks like a hint that this file is not compiled

Compilation error is confirmed

kkoutsilis · 2025-10-26T20:34:47Z

Github, generate report for configs in PR description

github-actions · 2025-10-26T21:01:05Z

https://checkstyle-diff-reports.s3.us-east-2.amazonaws.com/6ab16cb33f43b98353e4ce8cc0189e23023f7a30_2025210042/reports/diff/index.html

romani · 2025-10-30T01:21:08Z

Github, generate report for configs in PR description

romani · 2025-10-30T01:28:30Z

If you have time please send update
To
https://github.com/checkstyle/test-configs/blob/9ff74105f0f9bbceeca9f3ccb8f6d28a2e548682/extractor/src/main/resources/all-projects.yml#L38
https://github.com/checkstyle/test-configs/blob/9ff74105f0f9bbceeca9f3ccb8f6d28a2e548682/extractor/src/main/resources/list-of-projects.yml#L38

To exclude such non compiled files, so it will be bother us in diff , and we will see more clean validation.
If you can grep whole jdk21 by compile/fail to give more comprehensive update of file we should not deal at all, it will awesome.

And at https://github.com/checkstyle/test-configs/blob/9ff74105f0f9bbceeca9f3ccb8f6d28a2e548682/extractor/src/main/resources/all-projects.properties#L14

github-actions · 2025-10-30T01:56:24Z

https://checkstyle-diff-reports.s3.us-east-2.amazonaws.com/21f8aee60b4b792f41972b6a178c8314c85cee83_2025015606/reports/diff/index.html

romani · 2025-10-30T15:37:02Z

https://checkstyle-diff-reports.s3.us-east-2.amazonaws.com/21f8aee60b4b792f41972b6a178c8314c85cee83_2025015606/reports/diff/openjdk21/index.html#A2 this is interesting, can you explain?

https://github.com/openjdk/jdk21/blob/890adb6410dab4606a4f26a942aed02fb2f55387/src/java.base/share/classes/java/io/FileDescriptor.java#L333

    synchronized void closeAll(Closeable releaser) throws IOException {
        if (!closed) {
            closed = true;
            IOException ioe = null;
            try (releaser) {

This means that releaser will be closed after try. We can not put _ here.
Please add this to inputs, there should be no violation on resources that just referenced, please make input with multiple references in single try.

kkoutsilis · 2025-11-05T18:01:16Z

https://checkstyle-diff-reports.s3.us-east-2.amazonaws.com/21f8aee60b4b792f41972b6a178c8314c85cee83_2025015606/reports/diff/openjdk21/index.html#A2 this is interesting, can you explain?

https://github.com/openjdk/jdk21/blob/890adb6410dab4606a4f26a942aed02fb2f55387/src/java.base/share/classes/java/io/FileDescriptor.java#L333
    synchronized void closeAll(Closeable releaser) throws IOException {
        if (!closed) {
            closed = true;
            IOException ioe = null;
            try (releaser) {
This means that releaser will be closed after try. We can not put _ here. Please add this to inputs, there should be no violation on resources that just referenced, please make input with multiple references in single try.

This is identified as unused as releaser is not referenced anywhere inside the try block. Probably need to keep track of parameter definitions and exclude those from the check. Need to think about it, it's getting more complicated than I initially expected 😅

romani · 2025-11-06T05:21:48Z

I think this is very special way to reference in try, we should ignore such code - when it is not declared in "try".

romani · 2025-11-09T22:48:41Z

@kkoutsilis , please resolve conflict

SteLeo1602 · 2026-03-14T03:31:25Z

Can potentially be on it soon

aclfe · 2026-03-18T11:41:37Z

@romani @SteLeo1602 This check has some complications similar to JavadocUtilizingTrailingSpace that I've finished.
I am on it

SteLeo1602 · 2026-03-24T18:45:39Z

@romani @SteLeo1602 This check has some complications similar to JavadocUtilizingTrailingSpace that I've finished. I am on it

Can you confirm you are working on it right now?

aclfe · 2026-03-24T18:58:46Z

Can you confirm you are working on it right now?

#19359
The check is finished, it needs reviewing

kkoutsilis commented May 14, 2025

View reviewed changes

Comment thread ...le/checks/coding/unusedtryresourceshouldbeunnamed/InputUnusedTryResourceShouldBeUnnamed.java Outdated

mahfouz72 reviewed May 14, 2025

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Comment thread ...ava/com/puppycrawl/tools/checkstyle/checks/coding/UnusedTryResourceShouldBeUnnamedCheck.java

kkoutsilis force-pushed the 15484 branch 2 times, most recently from 8b88111 to cdd82d4 Compare May 16, 2025 08:45

kkoutsilis force-pushed the 15484 branch from cdd82d4 to f5a717a Compare May 28, 2025 07:21

kkoutsilis commented May 28, 2025

View reviewed changes

Comment thread config/pitest-suppressions/pitest-coding-1-suppressions.xml Outdated

kkoutsilis commented May 28, 2025

View reviewed changes

Comment thread ...e/checks/coding/unusedtryresourceshouldbeunnamed/InputUnusedTryResourceShouldBeUnnamed2.java Outdated

kkoutsilis force-pushed the 15484 branch 2 times, most recently from da88cb2 to d0ba295 Compare May 28, 2025 20:39

kkoutsilis mentioned this pull request May 30, 2025

Config: New check UnusedTryResourceShouldBeUnnamed checkstyle/contribution#939

Open

kkoutsilis force-pushed the 15484 branch 2 times, most recently from 58c1ec8 to bd46ce7 Compare May 30, 2025 08:02

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kkoutsilis force-pushed the 15484 branch 2 times, most recently from 2a3b3e5 to 43f253c Compare June 1, 2025 14:02

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romani requested changes Oct 21, 2025

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kkoutsilis force-pushed the 15484 branch from f71136d to 6ab16cb Compare October 26, 2025 17:06

kkoutsilis commented Oct 26, 2025

View reviewed changes

Issue checkstyle#15484: New check UnusedTryResourceShouldBeUnnamed

21f8aee

kkoutsilis force-pushed the 15484 branch from 6ab16cb to 21f8aee Compare October 29, 2025 17:26

romani mentioned this pull request Dec 9, 2025

Issue #17437: Add new skipAnnotations property to NoLineWrapCheck #18244

Open

romani added the abandoned label Feb 1, 2026


		try (AutoCloseable b = lock()) { // warn

		} catch (Exception e) {

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