Yeah, I don't think this is Quibble's fault exactly. In my local environment just running composer phpunit:unit I get:

> phpunit --colors=always --testsuite=core:unit,extensions:unit,skins:unit
PHP Fatal error:  Cannot declare class AbuseFilterVariableGeneratorTest, because the name is already in use in /Users/kostajh/src/mediawiki/w/extensions/AbuseFilter/tests/phpunit/Unit/AbuseFilterVariableGeneratorTest.php on line 24

Fatal error: Cannot declare class AbuseFilterVariableGeneratorTest, because the name is already in use in /Users/kostajh/src/mediawiki/w/extensions/AbuseFilter/tests/phpunit/Unit/AbuseFilterVariableGeneratorTest.php on line 24

I haven't tried to track this down yet. (cc @Daimona in case you've got any ideas)

The Unit subdirectory looks suspicious.

Same in Zeljko paste:

/workspace/src/skins/Vector/tests/phpunit/Unit/FeatureManagement/FeatureManagerTest.php
                                          ^^^^

Can it depends on the case sensitiveness of the underlying filesystem? I can't reproduce.

In T278707#6954567, @hashar wrote:

Can it depends on the case sensitiveness of the underlying filesystem? I can't reproduce.

I was sure I've mentioned it in the task, but I didn't. 🤦‍♂️ I was running this on a Mac.

I am pretty sure it is not related to Quibble so flagging with the generic MediaWiki-Core-Tests instead.

The only thing I can find related to the upper case Unit is:

<testsuite name="extensions:unit">
    <directory>extensions/**/tests/phpunit/unit</directory>  
    <directory>extensions/**/tests/phpunit/Unit</directory>  
</testsuite>
<testsuite name="skins:unit">
    <directory>skins/**/tests/phpunit/unit</directory>       
    <directory>skins/**/tests/phpunit/Unit</directory>       
</testsuite>

So I can imagine that when PHPUnit crawls through Vector using the lower case skins/**/tests/phpunit/unit it finds the test class and load it. Then PHPUnit crawls the path having an upper case (skins/**/tests/phpunit/Unit) and assuming the filesystem is case insensitive that yields the same PHP class which is loaded a second time. Duplicate class, failure.

That has been introduced back in 2019 apparently, I imagine to support unit tests being placed by Windows developers (the OS would use an upper case first name when creating a directory).

The only case we have would be four extensions for which we can rename Unit to unit:

$ ls -1d {extensions,skins}/*/tests/phpunit/Unit

ls: cannot access 'skins/*/tests/phpunit/Unit': No such file or directory

extensions/ChessBrowser/tests/phpunit/Unit/
extensions/DumpsOnDemand/tests/phpunit/Unit/
extensions/Lingo/tests/phpunit/Unit/
extensions/WikibaseQualityConstraints/tests/phpunit/Unit/

Once they got renamed, we can remove the wildcard in mediawiki/core phpunit.xml.dist pasted above, update whatever documentation we have as to how an extension or skin should be structured and I think that will resolve the task.

In T278707#6956541, @hashar wrote:

I am pretty sure it is not related to Quibble so flagging with the generic MediaWiki-Core-Tests instead.

It would probably make sense to rename the task too. I'm not sure what the problem is, so I'm hesitant to rename it myself.

In T278707#6956541, @hashar wrote:

I am pretty sure it is not related to Quibble so flagging with the generic MediaWiki-Core-Tests instead.

The only thing I can find related to the upper case Unit is:

phpunit.xml.dist

<testsuite name="extensions:unit">
    <directory>extensions/**/tests/phpunit/unit</directory>  
    <directory>extensions/**/tests/phpunit/Unit</directory>  
</testsuite>
<testsuite name="skins:unit">
    <directory>skins/**/tests/phpunit/unit</directory>       
    <directory>skins/**/tests/phpunit/Unit</directory>       
</testsuite>

So I can imagine that when PHPUnit crawls through Vector using the lower case skins/**/tests/phpunit/unit it finds the test class and load it. Then PHPUnit crawls the path having an upper case (skins/**/tests/phpunit/Unit) and assuming the filesystem is case insensitive that yields the same PHP class which is loaded a second time. Duplicate class, failure.

That has been introduced back in 2019 apparently, I imagine to support unit tests being placed by Windows developers (the OS would use an upper case first name when creating a directory).

The only case we have would be four extensions for which we can rename Unit to unit:

$ ls -1d {extensions,skins}/*/tests/phpunit/Unit

ls: cannot access 'skins/*/tests/phpunit/Unit': No such file or directory

extensions/ChessBrowser/tests/phpunit/Unit/
extensions/DumpsOnDemand/tests/phpunit/Unit/
extensions/Lingo/tests/phpunit/Unit/
extensions/WikibaseQualityConstraints/tests/phpunit/Unit/

Once they got renamed, we can remove the wildcard in mediawiki/core phpunit.xml.dist pasted above, update whatever documentation we have as to how an extension or skin should be structured and I think that will resolve the task.

Well spotted @hashar!

@zeljkofilipin can you prepare patches for the affected repositories and to drop Unit from phpunit.xml.dist please? I will be happy to review / guide / approve such patches :]

@hashar gladly, but I'm very busy with other things. I'll move it to my backlog and work on it when I have the time.

Change 740259 had a related patch set uploaded (by Kosta Harlan; author: Kosta Harlan):

[mediawiki/core@master] Revert \"Discover unit tests in \"Unit\" directory\"

https://gerrit.wikimedia.org/r/740259

Change 740326 had a related patch set uploaded (by Kosta Harlan; author: Kosta Harlan):

[mediawiki/extensions/WikibaseQualityConstraints@master] Rename Unit directory to unit

https://gerrit.wikimedia.org/r/740326

Change 740327 had a related patch set uploaded (by Kosta Harlan; author: Kosta Harlan):

[mediawiki/extensions/DumpsOnDemand@master] phpunit: Rename Unit directory to unit

https://gerrit.wikimedia.org/r/740327

Change 740328 had a related patch set uploaded (by Kosta Harlan; author: Kosta Harlan):

[mediawiki/extensions/Lingo@master] phpunit: Rename Unit directory to unit

https://gerrit.wikimedia.org/r/740328

Change 740259 merged by jenkins-bot:

[mediawiki/core@master] Revert \"Discover unit tests in \"Unit\" directory\"

https://gerrit.wikimedia.org/r/740259

Change 740326 merged by jenkins-bot:

[mediawiki/extensions/WikibaseQualityConstraints@master] Rename Unit directory to unit

https://gerrit.wikimedia.org/r/740326

My understanding is that uppercase Unit is supported for better PSR-4 compliance: for example, WikibaseQualityConstraints configures

"TestAutoloadNamespaces": {
    "WikibaseQuality\\ConstraintReport\\Tests\\": "tests/phpunit/"
},

and therefore the correct path for the class WikibaseQuality\ConstraintReport\Tests\Unit\ItemIdSnakValueTest is tests/phpunit/Unit/ItemIdSnakValueTest.php, with uppercase Unit, not lowercase unit.

I can see some value in standardizing on one capitalization, but why does it have to be the lowercase one? Uppercase is better for PSR-4 (unless we want to start having lowercased namespace names, in deviation from our usual practice); does lowercase have any advantages?

In T278707#7520022, @Lucas_Werkmeister_WMDE wrote:

My understanding is that uppercase Unit is supported for better PSR-4 compliance: for example, WikibaseQualityConstraints configures

"TestAutoloadNamespaces": {
    "WikibaseQuality\\ConstraintReport\\Tests\\": "tests/phpunit/"
},

and therefore the correct path for the class WikibaseQuality\ConstraintReport\Tests\Unit\ItemIdSnakValueTest is tests/phpunit/Unit/ItemIdSnakValueTest.php, with uppercase Unit, not lowercase unit.

I agree that "Unit" is more correct than "unit".

I can see some value in standardizing on one capitalization, but why does it have to be the lowercase one? Uppercase is better for PSR-4 (unless we want to start having lowercased namespace names, in deviation from our usual practice); does lowercase have any advantages?

Because we'd have to mass rename a lot of directories from "unit" to "Unit", I suspect, whereas replacing Unit -> unit was three patches. We could go the way you propose, though. The lowercase is also consistent with how subdirectories exist in core, but that could be changed as well.

T166010: The Great Namespaceization Effort also seems relevant.

In T278707#7520022, @Lucas_Werkmeister_WMDE wrote:

I can see some value in standardizing on one capitalization, but why does it have to be the lowercase one? Uppercase is better for PSR-4 (unless we want to start having lowercased namespace names, in deviation from our usual practice); does lowercase have any advantages?

I was going to write the exact same thing yesterday, then didn't find the time to finish my comment.

In T278707#7520246, @kostajh wrote:

Because we'd have to mass rename a lot of directories from "unit" to "Unit", I suspect, whereas replacing Unit -> unit was three patches. We could go the way you propose, though.

I was going to say that we could have LibUp mass-rename the directories all around the place.

In T278707#7520256, @Daimona wrote:

In T278707#7520022, @Lucas_Werkmeister_WMDE wrote:

I can see some value in standardizing on one capitalization, but why does it have to be the lowercase one? Uppercase is better for PSR-4 (unless we want to start having lowercased namespace names, in deviation from our usual practice); does lowercase have any advantages?

I was going to write the exact same thing yesterday, then didn't find the time to finish my comment.

In T278707#7520246, @kostajh wrote:

Because we'd have to mass rename a lot of directories from "unit" to "Unit", I suspect, whereas replacing Unit -> unit was three patches. We could go the way you propose, though.

I was going to say that we could have LibUp mass-rename the directories all around the place.

OK. I suppose we should do that for the "integration" directory that exists in core and some extensions, and rename that to "Integration".

I hadn’t thought of Integration, but that seems fair enough; FWIW, several codesearch-indexed extensions already have an Integration directory (Lingo, DumpsOnDemand, Gravatar, and ProfessionalWiki’s GND and ExternalContent).

Re-titled to reflect that we're not specific pro-unit and anti-Unit.

Change 740327 abandoned by Kosta Harlan:

[mediawiki/extensions/DumpsOnDemand@master] phpunit: Rename Unit directory to unit

Reason:

Per discussion in T278707#7520022, we want to keep this as is

https://gerrit.wikimedia.org/r/740327

Change 740328 abandoned by Kosta Harlan:

[mediawiki/extensions/Lingo@master] phpunit: Rename Unit directory to unit

Reason:

Per discussion in T278707#7520022, we want to keep this as is

https://gerrit.wikimedia.org/r/740328