Add `splitTestsCompilation` solidity setting: main PR by alcuadrado · Pull Request #8127 · NomicFoundation/hardhat

alcuadrado · 2026-04-12T22:01:06Z

Adds a splitTestsCompilation Solidity setting that controls if tests are built independently or not.

Docs PR: NomicFoundation/hardhat-website#255

changeset-bot · 2026-04-12T22:01:13Z

🦋 Changeset detected

Latest commit: ff3109b

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 6 packages

Name	Type
@nomicfoundation/hardhat-node-test-runner	Patch
@nomicfoundation/hardhat-typechain	Patch
@nomicfoundation/hardhat-ignition	Patch
@nomicfoundation/hardhat-mocha	Patch
@nomicfoundation/hardhat-errors	Patch
hardhat	Minor

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Copilot

Pull request overview

Adds a standalone specification document describing the planned introduction of a new top-level Solidity config field, splitTestsCompilation, to control whether Solidity tests are compiled separately or together with contracts (defaulting to unified compilation).

Changes:

Add SPLIT_TESTS_COMPILATION_SPEC.md documenting intended behavior changes across Hardhat build system, tasks, cache, and related plugins.
Outline a phased implementation plan (config/plumbing → build system semantics → cache → tasks/runners/plugins → docs/migration).

…be already adapted.

…r not in the CompileCacheEntry interface

…th unified compilations

…-phase-6 Add `splitTestsCompilation` solidity setting (6): Solidity test runner updates

…-phase-7 Add `splitTestsCompilation` solidity setting (7): Typechain updates

…-phase-8 Add `splitTestsCompilation` solidity setting (8): Mocha updates

…-phase-9 Add `splitTestsCompilation` solidity setting (9): `node:test` updates

Copilot

Pull request overview

Copilot reviewed 43 out of 47 changed files in this pull request and generated 2 comments.

…-phase-10 Add `splitTestsCompilation` solidity setting (10): `hardhat-ignition` updates

Co-authored-by: Luis Schaab <schaable@gmail.com>

…-phase-11 Add `splitTestsCompilation` solidity setting (11): closing PR

Copilot

Pull request overview

Copilot reviewed 48 out of 52 changed files in this pull request and generated 4 comments.

Copilot · 2026-04-16T16:45:43Z

+        (suiteResult) => {
+          stream.push({
+            type: "suite:done",
+            data: suiteResult,
+          } satisfies TestEvent);
+          remainingSuites.delete(
+            formatArtifactId(suiteResult.id, sourceNameToUserSourceName),
+          );
+          if (remainingSuites.size === 0) {
+            if (runCompleted) {
+              stream.push(null);
+            }
+          }
+        },
+      );
+      stream.push({
+        type: "run:done",
+        data: solidityTestResult,
+      } satisfies TestEvent);
+      runCompleted = true;

-        controller.error(
-          new HardhatError(
-            HardhatError.ERRORS.CORE.SOLIDITY_TESTS.UNHANDLED_EDR_ERROR_SOLIDITY_TESTS,
-            {
-              error: error.message,
-            },
-          ),
-        );
+      if (remainingSuites.size === 0) {
+        stream.push(null);
      }


stream.push(null) can be called from both the suite callback (when runCompleted is true) and after runSolidityTests resolves. If the EDR callback can fire after runSolidityTests resolves, this risks pushing EOF twice, which can trigger ERR_STREAM_PUSH_AFTER_EOF. Consider centralizing stream termination in a helper (e.g. endOnce()) or guarding with stream.readableEnded/stream.destroyed before pushing null.

Copilot · 2026-04-16T16:45:43Z

+    let scope = scopeBySource.get(sourceName);
+    if (scope === undefined) {
+      const fsPath = path.resolve(projectRoot, sourceName);
+
+      // npm files will be classified as "contracts" because their sourceName is
+      // not an existing file, and "contracts" is the default.
+      //
+      // If the package name clashed with
+      // ```ts
+      //  path.relative(
+      //    context.config.paths.root,
+      //    context.config.paths.tests.solidity
+      //  )
+      // ```
+      //
+      // They could be misclassified as test files. This is highly improbable,
+      // so we don't check it. You could read the artifact and see if the
+      // inputSourceName starts with `npm/` to rule this out.
+      scope = await context.solidity.getScope(fsPath);
+      scopeBySource.set(sourceName, scope);
+    }


In unified mode, getContractArtifactPaths resolves each artifact sourceName to path.resolve(projectRoot, sourceName) and then calls context.solidity.getScope(fsPath). For npm-dependency artifacts, sourceName is not an on-disk project file, and this can be misclassified as a test if the package name matches the configured Solidity tests directory (e.g. test/... with paths.tests.solidity = "test"), causing types to be skipped incorrectly. Consider treating non-existent paths as npm sources (defaulting to "contracts"), or detecting npm artifacts via artifact metadata (e.g. input/source name prefix) instead of relying on getScope for paths that don't exist.

Copilot · 2026-04-16T16:45:44Z

@@ -0,0 +1 @@
+// Empty file to trigger the full CI


The PR description says this PR only adds a spec file and isn't meant to be reviewed, but the diff includes substantial production and test changes across multiple packages (build system behavior, errors, plugin integration tests, fixture projects, etc.). Please update the PR description to reflect the actual scope (or split/retitle the PR) to avoid confusion during review and release notes.

Copilot · 2026-04-16T16:45:44Z

@@ -0,0 +1 @@
+// Empty file to trigger the full CI


This placeholder source file under src/internal/ looks like it’s only meant to force CI to run. Please remove it (or move the CI trigger to a non-shipping location) before merging, so it doesn’t accidentally get released/published.

Copilot

Pull request overview

Copilot reviewed 49 out of 53 changed files in this pull request and generated 3 comments.

Copilot · 2026-04-16T16:53:36Z

+  if (hre.config.solidity.splitTestsCompilation) {
+    if (noCompile !== true) {
+      await hre.tasks.getTask("build").run({
+        noTests: true,
+      });
+    }

-  // EDR needs all artifacts (contracts + tests)
-  const edrArtifactsWithMetadata: EdrArtifactWithMetadata[] = [];
-  const allBuildInfosAndOutputs: BuildInfoAndOutput[] = [];
-  for (const scope of ["contracts", "tests"] as const) {
-    const artifactsDir = await hre.solidity.getArtifactsDirectory(scope);
-    const artifactManager = new ArtifactManagerImplementation(artifactsDir);
-    edrArtifactsWithMetadata.push(
-      ...(await buildEdrArtifactsWithMetadata(artifactManager)),
-    );
-    allBuildInfosAndOutputs.push(
-      ...(await getBuildInfosAndOutputs(artifactManager)),
-    );
+    ({ testRootPaths: testRootPathsToRun } = await hre.tasks
+      .getTask("build")
+      .run({
+        files: testFiles,
+        noContracts: true,
+      }));
+    console.log();


In splitTestsCompilation mode, the --no-compile flag is only skipping the contracts build, but still always runs hre.tasks.getTask("build").run({ files: testFiles, noContracts: true }), which compiles the project despite the flag (the task option description says it should not compile the project). Consider skipping both build invocations when noCompile === true, and instead: (1) compute testRootPathsToRun from testFiles (resolved) or solidity.getRootFilePaths({ scope: "tests" }), (2) load artifacts from both scopes, and (3) validate that the selected test roots have compiled artifacts (similar to the unified-mode branch).

Copilot · 2026-04-16T16:53:36Z

+      //
+      // They could be misclassified as test files. This is highly improbable,
+      // so we don't check it. You could read the artifact and see if the
+      // inputSourceName starts with `npm/` to rule this out.


This comment refers to npm/ as the prefix for npm sources, but the Solidity build system root-path format uses the npm: prefix (e.g. npm:<package>/<file>). Updating the comment to match the actual prefix would avoid confusion for future maintainers.

Suggested change

// inputSourceName starts with `npm/` to rule this out.

// inputSourceName starts with `npm:` to rule this out.

Copilot · 2026-04-16T16:53:37Z

+"hardhat": minor
+---
+
+Make the split of contracts and solidity tests compilation optional, and controlled with a new `splitTestsCompilation` config field.


PR description says this PR “only introduces a spec file” and is “not meant to be reviewed”, but this changeset (and the diff overall) indicates the feature is being implemented and released (new config field, error descriptors, build-system behavior, multiple tests/fixtures). Please update the PR description to match the actual scope of changes, or split out the spec-only PR if that’s still the intent.

Add spec

8ada49c

alcuadrado requested a review from Copilot April 12, 2026 22:37

Copilot started reviewing on behalf of alcuadrado April 12, 2026 22:37 View session

Copilot AI reviewed Apr 12, 2026

View reviewed changes

Comment thread SPLIT_TESTS_COMPILATION_SPEC.md Outdated

Comment thread SPLIT_TESTS_COMPILATION_SPEC.md Outdated

alcuadrado added 25 commits April 13, 2026 06:27

Fix typos and cspell config

a99a5b9

Add config field to the builtin:solidity type extensions

d72d7c1

Add config validation and resolution

dbaec84

Fix some tests that construct SolidityConfig objects manually

be8bf71

Throw in the disabled apis

8f5c52b

Update getRootFilePaths()

b6c93bf

Update emitArtifacts()

7fd2e2b

Update getArtifactsDirectory()

35752f6

Remove outdated assertion

6f75b54

Fix existing build scope tests, as they were based on split mode

2e1a389

Add tests for the new behavior

1b26dd5

Update the plan so that phase 4 fixes the tests that needed build to …

770b1be

…be already adapted.

Reintroduced accidentally deleted descriptor

b3c2444

Reintroduced accidentally deleted jsdoc

d863c0e

Tiny optimization to getScope()

9b79ed8

Make test portable

ed5c4c5

Include the artifacts directory and if a root file emitted ts types o…

832063f

…r not in the CompileCacheEntry interface

Address copilot feedback

69a4ed0

Add missing test

9518909

Document expected failures after this phase

dff3b3d

Update the spec to simplify how --no-contracts and --no-tests work wi…

47f513f

…th unified compilations

Update build-cleanup-artifacts tests to run full builds

aeeab09

Update the build task

fe0400a

Adds SolidityBuildSystem tests for splitTestCompilation:false behavior

4c56c96

Add cleanup artifacts tests for unified builds

42170c7

alcuadrado added 5 commits April 16, 2026 13:36

Add a comment

c67029d

Merge pull request #8133 from NomicFoundation/dont-split-compilations…

5697e12

…-phase-6 Add `splitTestsCompilation` solidity setting (6): Solidity test runner updates

Merge pull request #8134 from NomicFoundation/dont-split-compilations…

3b58254

…-phase-7 Add `splitTestsCompilation` solidity setting (7): Typechain updates

Merge pull request #8135 from NomicFoundation/dont-split-compilations…

021fe6e

…-phase-8 Add `splitTestsCompilation` solidity setting (8): Mocha updates

Merge pull request #8136 from NomicFoundation/dont-split-compilations…

b61878e

…-phase-9 Add `splitTestsCompilation` solidity setting (9): `node:test` updates

Copilot AI reviewed Apr 16, 2026

View reviewed changes

Comment thread ...ages/hardhat/test/internal/builtin-plugins/solidity/build-system/integration/build-scopes.ts

Comment thread ...ages/hardhat/test/internal/builtin-plugins/solidity/build-system/integration/build-scopes.ts

alcuadrado and others added 4 commits April 16, 2026 13:38

Merge pull request #8137 from NomicFoundation/dont-split-compilations…

f94b313

…-phase-10 Add `splitTestsCompilation` solidity setting (10): `hardhat-ignition` updates

Update PLUGIN_MIGRATION_GUIDE.md

32c5c1c

Co-authored-by: Luis Schaab <schaable@gmail.com>

Update PLUGIN_MIGRATION_GUIDE.md

2931710

Co-authored-by: Luis Schaab <schaable@gmail.com>

Merge pull request #8138 from NomicFoundation/dont-split-compilations…

fbe80d4

…-phase-11 Add `splitTestsCompilation` solidity setting (11): closing PR

Copilot AI review requested due to automatic review settings April 16, 2026 16:39

Copilot started reviewing on behalf of alcuadrado April 16, 2026 16:39 View session

Add hardhat changseet

353cf86

Copilot AI reviewed Apr 16, 2026

View reviewed changes

alcuadrado added 4 commits April 16, 2026 13:45

Add plugins changesets

4fe12fe

Add peer bumps

e3b5324

Delete plugin migration guide

7fb929e

Delete empty file

ff3109b

Copilot AI review requested due to automatic review settings April 16, 2026 16:47

Copilot started reviewing on behalf of alcuadrado April 16, 2026 16:47 View session

Copilot AI reviewed Apr 16, 2026

View reviewed changes

alcuadrado enabled auto-merge April 16, 2026 16:57

ChristopherDedominici approved these changes Apr 16, 2026

View reviewed changes

alcuadrado added this pull request to the merge queue Apr 16, 2026

github-merge-queue Bot removed this pull request from the merge queue due to failed status checks Apr 16, 2026

alcuadrado added this pull request to the merge queue Apr 16, 2026

Merged via the queue into main with commit 5995f0f Apr 16, 2026
263 of 264 checks passed

alcuadrado deleted the dont-split-compilations branch April 16, 2026 17:24

github-actions Bot mentioned this pull request Apr 16, 2026

Version Packages (v3) #8099

Merged

	// inputSourceName starts with `npm/` to rule this out.
	// inputSourceName starts with `npm:` to rule this out.

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