Partially support isolated projects by inorichi · Pull Request #2854 · diffplug/spotless

inorichi · 2026-02-20T14:41:14Z

This PR adds partial support for isolated projects.

They're supported as long as predeclareDeps() is not called in the root extension.

The PR does the following:

Removes .getRootProject.file(...) since it's not supported by isolated projects.
Removes the GradleCompat file because project.findProperty and project.hasProperty can't be used and the compat file is not meaningful anymore.
Moves the SpotlessTaskService reference from RegisterDependenciesTask to SpotlessExtension as the task is not really owning the task service. This simplifies some dependencies needing to get the task reference first.
Makes the SpotlessExtension not reference the RegisterDependenciesTask which is created in the root project and moves all of that to SpotlessExtensionPredeclare. Since this task is only needed (AFAIK) for predeclared, it makes sense that the task is only referenced there.
Some tests needed adjustments because RegisterDependenciesTask is not executed when predeclared is not used.
Adds a test that verifies isolated projects compatibility.

nedtwigg · 2026-02-20T17:38:58Z

Wonderful! Looks like it needs a ./gradlew spotlessApply before CI can check it. Will also need changelog entries and doc updates where appropriate.

…perties

inorichi · 2026-02-20T19:26:44Z

Fixed. Sorry I rebased and force pushed the changes, it's an habit of mine...

I added the changelog entry, but I'm not sure where I should update the documentation.

nedtwigg · 2026-02-20T20:54:51Z

I'm not sure where I should update the documentation.

https://github.com/diffplug/spotless/tree/main/plugin-gradle#dependency-resolution-modes

This should have a note of some kind saying "breaks isolated projects" or something like that.

Assuming CI passes and no other contributors have any objections, I'll merge and release next week.

…ependencies

inorichi · 2026-02-21T09:23:37Z

I added a note where you suggested, let me know if it's good enough.

Regarding CI, it seems like there are different isolated project error outputs, while I get the following locally:

- Build file '0/build.gradle': Cannot access project ':' from project ':0'

CI sees this:

- Build file '0/build.gradle': Project ':0' cannot access 'Project.tasks' functionality on another project ':'

And that breaks the test I created. I don't understand the difference, since I'm running the gradle wrapper too and should run the same gradle version. I'll investigate...

inorichi · 2026-02-21T09:59:59Z

Okay, it seems like CI was executing that test on Gradle 9, and the message is different on that version, I've changed the test to .containsAnyOf("Cannot access project", "cannot access 'Project.tasks'") so that Gradle 8 and 9 are supported.

Edit: I just saw that GradleIntegrationHarness runs different gradle versions based on the JDK used, that's what happened.

In anticipation of diffplug/spotless#2854.

Goooler · 2026-02-21T00:43:30Z

plugin-gradle/src/main/java/com/diffplug/gradle/spotless/BaseKotlinExtension.java

 				List<String> customRuleSets) throws IOException {
 			Objects.requireNonNull(version);
-			File defaultEditorConfig = getProject().getRootProject().file(".editorconfig");
+			File defaultEditorConfig = new File(getProject().getRootDir(), ".editorconfig");


Use project.isolated.rootProject.projectDirectory.file(".editorconfig") instead.

It doesn't work with the min Gradle requirement, need to add glue.

Added a new commit. .getLayout() seems to be IP safe so no need to use unstable APIs

Let me check something, I think the IP test is not calling that code and is giving a false hope.

I think I'll create a separate test file for testing IP. I added ktlint to the tests in MultiProjectTest and they still work, even with the old getProject().getRootProject().file(".editorconfig"), and this is really weird as this was giving me issues when I was testing on a real project.

I don't have time right now to check all of this, I'll try to take another look later.

Edit: I needed to apply ktlint on the subprojects, now the tests are failing even with .getLayout() so my previous assertion was totally wrong.

new File(getProject().getRootProject().getProjectDir(), ".editorconfig"); is compatible with IP, which should be the same as getProject().getRootProject().file(".editorconfig");. I updated my PR to use that and separated the test to another file.

I'm only testing ktlint on the test, as that's the only formatter that was not compatible with IP, but maybe all the formatters should be tested? Or maybe they should only be checked when/if they break.

Edit: I've also reverted the test to use gradle.properties because then it's enabled for all tests in this file, and the same approach is used by the configuration cache tests.

plugin-gradle/src/main/java/com/diffplug/gradle/spotless/GradleCompat.java

Goooler · 2026-03-02T09:15:13Z

plugin-gradle/src/main/java/com/diffplug/gradle/spotless/SpotlessTaskService.java

+		if (!isUsingPredeclared)
+			return;
+
+		project.getRootProject().getTasks().withType(RegisterDependenciesTask.class, (registerTask) -> {


Calling getRootProject().getTasks() looks unsafe for IP.

Yes, that's the only incompatibility remaining (hence the partial support in the title), I added a comment about it in line 132.

This affects only the predeclared dependencies, which I think should not be used alongside isolated projects.

All right. Let's leave it here. I couldn't find a replacement for it either.

plugin-gradle/src/test/java/com/diffplug/gradle/spotless/MultiProjectTest.java

…bility

inorichi mentioned this pull request Feb 20, 2026

Support Gradle Project Isolation #1979

Open

inorichi force-pushed the feature/isolated_projects branch from 3db843d to 611af68 Compare February 20, 2026 18:38

inorichi added 3 commits February 20, 2026 19:40

Make BaseKotlinExtension compatible with isolated projects

9d64197

Remove GradleCompat and always use project providers for querying pro…

2bf655b

…perties

Make non-predeclared spotless compatible with isolated projects

f7829b5

inorichi force-pushed the feature/isolated_projects branch from 611af68 to f7829b5 Compare February 20, 2026 18:40

Add changelog for isolated projects

bebb746

inorichi force-pushed the feature/isolated_projects branch from 41e3f19 to bebb746 Compare February 20, 2026 19:25

nedtwigg requested a review from Goooler February 20, 2026 20:54

Add a note about isolated projects incompatibility with predeclared d…

5299998

…ependencies

Fix isolated project tests

9ac74d3

VegetalDev added a commit to Echoes-from-Beyond/echoes-from-beyond that referenced this pull request Feb 24, 2026

chore: isolated project support

b848595

In anticipation of diffplug/spotless#2854.

Goooler reviewed Mar 1, 2026

View reviewed changes

inorichi and others added 3 commits March 2, 2026 09:24

Use isolated project for accessing root project files

fd20a1f

Restore GradleCompat with IP safe approach

13d4045

Clean up GradleCompat

4e9839f

Goooler reviewed Mar 2, 2026

View reviewed changes

inorichi added 2 commits March 2, 2026 10:25

Use gradle arguments for isolated projects tests

bc57868

Use root project layout for retrieving editorconfig

c336483

inorichi force-pushed the feature/isolated_projects branch from 27c3007 to c336483 Compare March 2, 2026 10:19

Goooler approved these changes Mar 2, 2026

View reviewed changes

Move isolated project tests to separate file and fix ktlint incompati…

2519190

…bility

inorichi force-pushed the feature/isolated_projects branch from e2a5b92 to 2519190 Compare March 2, 2026 15:37

Merge branch 'main' into feature/isolated_projects

20a7126

nedtwigg enabled auto-merge March 2, 2026 22:45

nedtwigg merged commit a91afd1 into diffplug:main Mar 2, 2026
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inorichi commented Feb 21, 2026 •

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