Issue #17841: Add GoogleMethodNameCheck to fix method name false nega… #18312

vivek-0509 · 2025-12-15T22:50:01Z

Description

Introduces a new GoogleMethodName check that properly validates method names according to the Google Java Style Guide, fixing false-negatives where underscores between letters and digits were not being flagged.

Problem

The previous MethodName check failed to detect invalid names like:

gradle_9_5_1() - underscore between letter 'e' and digit '9'
jdk_9_0_392() - underscore between letter 'k' and digit '9'

Solution

Created a dedicated GoogleMethodName check that:

Has no configurable properties
Uses multi-pattern validation instead of one complex regex
Handles @Test methods separately (underscores allowed)
Properly validates numbering suffixes (guava33_4_5 is valid)

Validation Rules

Regular Methods:

Must be in lowerCamelCase
Underscores only between adjacent digits (_4_5)
Not between letter and digit (gradle_9 invalid)

Test Methods (@Test, @ParameterizedTest, @RepeatedTest):

Underscores allowed to separate components
Each segment must be lowerCamelCase
Each segment must be at least 2 characters
Segments cannot start with single lowercase followed by uppercase (e.g., fO)

Override Methods:

Methods with @Override annotation are skipped (no validation)

Breaking Changes

None. This check is backward compatible with the previous MethodName regex behavior.

New module config: https://gist.githubusercontent.com/vivek-0509/6733c4a828cc940c59db1c7af371a806/raw/4758b044822977e75ba30138eefa3a9b3c2026f7/google-method-name.xml

Contirbution repo PR: checkstyle/contribution#1000

…false negatives

vivek-0509 · 2025-12-16T12:00:02Z

The CI Failures are unrelated

vivek-0509 · 2025-12-16T12:10:04Z

Github, generate report for GoogleMethodName/all-examples-in-one

github-actions · 2025-12-16T12:11:18Z

Failed to download or process the specified configuration(s).
Error details:

Please ensure you've used one of the following commands correctly:

'GitHub, generate report for <config_bundle_path>'
'GitHub, generate report by config from <file_path>'
'GitHub, generate report for configs in PR description'

And check that all specified configs or files exist and are valid.

Link: https://github.com/checkstyle/checkstyle/actions/runs/20267426773

vivek-0509 · 2025-12-17T04:31:54Z

GitHub, generate report

vivek-0509 · 2025-12-17T04:46:21Z

GitHub, generate report

vivek-0509 · 2025-12-17T05:03:30Z

GitHub, generate report

github-actions · 2025-12-17T05:14:20Z

Report generation failed on phase "make_report",
step "Generate report".
Link: https://github.com/checkstyle/checkstyle/actions/runs/20292237473

vivek-0509 · 2025-12-17T05:21:23Z

GitHub, generate report

github-actions · 2025-12-17T05:59:25Z

https://checkstyle-diff-reports.s3.us-east-2.amazonaws.com/2f3db4a_2025055802/reports/diff/index.html

vivek-0509 · 2025-12-17T08:44:04Z

Hey @romani,
Here is the analysis of the report

Bug Found (Will Fix)

Issue: Test methods with numbering suffix like test3_1 are incorrectly rejected.

Cause: The implementation doesn't strip numbering suffix before validating test methods (unlike regular methods).

Examples:

test3_1 → Rejected (Should be valid - 3_1 = adjacent numbers)
testFoo_1_2 → Rejected (correctly invalid)

Fix: Will add numbering suffix stripping + INVALID_UNDERSCORE_PATTERN check for test methods.

Design Questions - Need Your Input

1. Minimum 2-character segment requirement for test methods

Currently rejects single lowercase character segments:

Examples:

t_name → Rejected (segment t = 1 char)
test_a → Rejected (segment a = 1 char)
test_foo → Valid (both segments ≥ 2 chars)

Real example:

@Test
void can_be_used_in_a_collector() {} //  Rejected (segment a fails)

Question: Should we keep the current 2-character minimum requirement, or should we make it stricter by requiring proper lowerCamelCase (at least 2 words joined with capitalization) for each segment in test method names?

2. Test methods without @test annotation

Examples:

void test_ctor_shouldThrow_whenPidIsMissing() → REJECTED (no annotation)
@Test void test_ctor_shouldThrow_whenPidIsMissing() → VALID

Supported annotations: @Test, @ParameterizedTest, @RepeatedTest

Question: Should test-style method names without annotations be rejected, as Google Style only mentions JUnit tests?

vivek-0509 · 2025-12-20T15:00:38Z

@romani ping

romani · 2025-12-23T16:12:30Z

@Zopsss , can you help me to review this PR?
while I am busy with general stream of PRs.

vivek-0509 · 2025-12-23T16:35:38Z

Will fix the CI asap , failures caused due to recent pr merge method access level for getPackageLocation() changed to pubilc

vivek-0509 · 2025-12-24T06:24:00Z

Hi @Zopsss ,

Before you review the code, I'd like to clarify my understanding of the expected rules for GoogleMethodNameCheck , as Google Style Guide is somewhat ambiguous in places.

For regular methods (without @Test), my implementation requires lowerCamelCase names where underscores are only allowed between adjacent numbers (like guava33_4_5). Names like gradle_9_5_1 with letter_digit underscores are flagged as invalid. Single letter names like f and patterns like fO are also rejected.

For test methods (with @Test, @ParameterizedTest, @RepeatedTest), underscores are allowed to separate logical components, with each component being lowerCamelCase. So transferMoney_deductsFromSource is valid, but test_1 is invalid because 1 is not lowerCamelCase and also it violates the no underscore between just number and digit. The numbering suffix rule also applies, so test3_1 is valid (adjacent numbers), but testFoo_1_2 is invalid (letter_digit pattern). For test methods like solve6x6_returnsTrue and solve6x6_noSolution_returnsFalse, my implementation treats them as valid since each component (solve6x6, returnsTrue, noSolution, returnsFalse) is lowerCamelCase and the underscore separates these components rather than being between a digit and letter within a component.

One thing I'm unclear about: Google Style says test components should be "lowerCamelCase". Strictly speaking, lowerCamelCase means multiple words joined with capitalization (like transferMoney). Should single-word components like test_foo be valid, or should we require multi-word lowerCamelCase like transferMoney_deductsFromSource?

If any of my expectations don't align with what's actually required, please let me know and I'll adjust my implementation before you do a full code review. This should save time .

src/main/java/com/puppycrawl/tools/checkstyle/checks/naming/GoogleMethodNameCheck.java

Zopsss · 2025-12-25T07:02:52Z

src/main/resources/com/puppycrawl/tools/checkstyle/checks/naming/messages.properties

@@ -1,4 +1,5 @@
 abbreviation.as.word=Abbreviation in name ''{0}'' must contain no more than ''{1}'' consecutive capital letters.
+google.method.name=Method name ''{0}'' is not valid per Google Java Style Guide.


this message does not explain why the method name is invalid. Instead we should keep different messages for the different conditions we hit to easily explain reason behind violation to the user.

please create separate messages for all the logs which should explain the reason behind the violation.

For the separate violation messages, I'm planning to add 4 messages (one per log point):

google.method.name.underscore.regular=Method name ''{0}'' has invalid underscore usage, underscores only allowed between adjacent digits. google.method.name.underscore.test=Method name ''{0}'' has invalid underscore usage, underscore only allowed between letters or between digits. google.method.name.format.regular=Method name ''{0}'' must be lowerCamelCase: start with lowercase, at least 2 characters, and avoid single lowercase followed by uppercase. google.method.name.format.test=Method name ''{0}'' is not valid: each segment must be lowerCamelCase: start lowercase, min 2 chars, avoid single lowercase followed by uppercase.

Does this approach work for you?

google.method.name.underscore.test=Method name ''{0}'' has invalid underscore usage, underscore only allowed between letters or between digits.

this one is for the test methods, so it should mention that it is for test methods.

google.method.name.format.regular=Method name ''{0}'' must be lowerCamelCase: start with lowercase, at least 2 characters, and avoid single lowercase followed by uppercase.

google.method.name.format.test=Method name ''{0}'' is not valid: each segment must be lowerCamelCase: start lowercase, min 2 chars, avoid single lowercase followed by uppercase.

it should end with: avoid single lowercase followed by uppercase or underscore.

it should end with: avoid single lowercase followed by uppercase or underscore.

but this still falls under invalid underscore usage, for example, f_ is not permitted because valid underscore usage is restricted to letter–letter or digit–digit only.
and for this case test_a message already mentions the min 2-chars required for each segment.

src/main/java/com/puppycrawl/tools/checkstyle/checks/naming/GoogleMethodNameCheck.java

vivek-0509 · 2025-12-25T17:40:04Z

Hi @Zopsss, thanks for the review
I’ve created an issue to clarify the expected scope and rules for this check: #18420

Would it be acceptable if I apply all the requested changes once we align on what exactly this check should cover and the set of rules to be enforced for this check?

romani · 2025-12-26T04:05:11Z

GitHub, generate report

github-actions · 2025-12-26T04:33:49Z

https://checkstyle-diff-reports.s3.us-east-2.amazonaws.com/2f3db4a_2025043249/reports/diff/index.html

romani · 2025-12-27T01:16:54Z

GitHub, generate report

github-actions · 2025-12-27T01:47:52Z

https://checkstyle-diff-reports.s3.us-east-2.amazonaws.com/2f3db4a_2025014602/reports/diff/index.html

Zopsss · 2025-12-29T17:50:07Z

GitHub, generate report

vivek-0509 marked this pull request as draft December 15, 2025 22:53

Issue checkstyle#17841: Add GoogleMethodNameCheck to fix method name …

2f3db4a

…false negatives

vivek-0509 mentioned this pull request Dec 16, 2025

Add GoogleMethodName to checks-nonjavadoc-error.xml checkstyle/contribution#1000

Open

vivek-0509 force-pushed the addingNewGoogleMethodNameCheck branch from 304a1ac to 2f3db4a Compare December 16, 2025 11:37

vivek-0509 marked this pull request as ready for review December 16, 2025 12:00

vivek-0509 marked this pull request as draft December 17, 2025 06:32

vivek-0509 marked this pull request as ready for review December 17, 2025 08:44

romani requested a review from Zopsss December 23, 2025 16:11

Zopsss reviewed Dec 25, 2025

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Zopsss suggested changes Dec 25, 2025

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romani mentioned this pull request Dec 26, 2025

Issue #980: Replace AntBuilder.copy() with Files.walkFileTree() checkstyle/contribution#1003

Merged

romani mentioned this pull request Dec 27, 2025

Issue #980: Replace AntBuilder.copy() with Files.walkFileTree() checkstyle/contribution#1006

Merged

		@@ -1,4 +1,5 @@
		abbreviation.as.word=Abbreviation in name ''{0}'' must contain no more than ''{1}'' consecutive capital letters.
		google.method.name=Method name ''{0}'' is not valid per Google Java Style Guide.

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Issue #17841: Add GoogleMethodNameCheck to fix method name false nega… #18312

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Issue #17841: Add GoogleMethodNameCheck to fix method name false nega… #18312

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Description

Problem

Solution

Validation Rules

Breaking Changes

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Bug Found (Will Fix)

Design Questions - Need Your Input

1. Minimum 2-character segment requirement for test methods

2. Test methods without @test annotation

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vivek-0509 commented Dec 20, 2025

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