[schaable]

--snapshot-check no longer writes or deletes snapshot files. It exits with an error only when a tracked gas value differs; snapshots added or missing relative to the baseline are reported for information only; a missing baseline is reported with a hint to run --snapshot. Output reworded to read-only language. Tests updated, with a regression test covering the scoped-run-deletes-group-files scenario from the issue.

Closes #8358.

Docs updated NomicFoundation/hardhat-website#278.

Screenshots

Added/removed snapshots

No baseline (fn snapshots)

No baseline (both)

Combined (failed + added + no baseline)

[changeset-bot]

🦋 Changeset detected

Latest commit: a52bd4c

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

This PR includes changesets to release 1 package

Name	Type
hardhat	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[Copilot]

Pull request overview

This PR updates Hardhat’s Solidity gas snapshot checking so hardhat test solidity --snapshot-check becomes strictly read-only: it no longer bootstraps, rewrites, or deletes snapshot baseline files on disk, and instead only reports differences (failing only on changed tracked values) with improved “read-only” wording.

Changes:

• Make --snapshot-check stop writing/updating .gas-snapshot and snapshots/*.json (including avoiding deletions on scoped runs).
• Replace “written” semantics with an explicit noBaseline signal and update log output to match the new behavior.
• Update and extend tests, including a regression test for the “scoped run deletes group files” scenario from #8358.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
packages/hardhat/src/internal/builtin-plugins/gas-analytics/function-gas-snapshots.ts	Removes baseline writes during snapshot-check; introduces noBaseline and updates logging for added/removed output wording.
packages/hardhat/src/internal/builtin-plugins/gas-analytics/snapshot-cheatcodes.ts	Removes baseline writes/deletions during snapshot-check; introduces noBaseline and adjusts log messaging for read-only behavior.
packages/hardhat/src/internal/builtin-plugins/gas-analytics/tasks/solidity-test/task-action.ts	Updates snapshot-check result logging conditions to use noBaseline instead of “written”.
packages/hardhat/test/internal/builtin-plugins/gas-analytics/tasks/solidity-test/task-action.ts	Updates assertions to validate read-only behavior and adds regression coverage for scoped runs not deleting snapshot group files.
.changeset/quiet-melons-wave.md	Adds a patch changeset documenting the read-only --snapshot-check behavior change.

[kanej]

I have gone through the changes and I have no feedback at the code level.

I left a few comments, but one change I think we should make:

• if filtering or a named file has been passed, we shouldn't show the added/removed sections

[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

[schaable]

@kanej I've addressed all of the requested changes. Can you take another look?