Make test threads number configurable via CLI #4055

Copilot · 2025-12-19T14:47:56Z

Introduced changes

Added --max-threads <N> CLI flag to control test parallelism
Thread selection follows precedence: CLI argument → auto-detect
Added validation to ensure --max-threads doesn't exceed available CPU cores
Program fails if CPU core detection is unavailable (for both manual and automatic thread configuration)

Usage:

snforge test --max-threads 4

When --max-threads is not specified, the number of threads defaults to the number of available CPU cores detected by the system. If --max-threads exceeds the available parallelism, the command will fail with a clear error message indicating the limit.

The command will fail if CPU core detection is not possible, ensuring consistent behavior regardless of whether --max-threads is provided.

Checklist

Original prompt

This section details on the original issue you should resolve

<issue_title>Make test threads number configurable</issue_title>
<issue_description>### Current State

Currently it's detected automatically and not configurable in anyway.

Objective

We should allow it to run with any number of thread limit

Additional Context

No response</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes Make test threads number configurable #4037

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

- Added --max-threads CLI argument to TestArgs - Added max_threads field to ForgeConfigFromScarb for Scarb.toml config - Updated main execution to use configurable threads with precedence: CLI > Scarb config > auto-detect - Updated Scarb template to document the new max_threads option Co-authored-by: cptartur <[email protected]>

- Added unit tests for max_threads deserialization in ForgeConfigFromScarb - Updated existing tests in combine_configs to include max_threads field Co-authored-by: cptartur <[email protected]>

- Added e2e test to verify --max-threads CLI option works correctly - Updated integration tests to include max_threads field in ForgeConfigFromScarb Co-authored-by: cptartur <[email protected]>

- Added clarifying comment that max_threads is read directly in main execution - This helps understand why the field isn't consumed by combine_configs Co-authored-by: cptartur <[email protected]>

cptartur

@copilot change the PR so that number of threads can only be set from the CLI and not in scarb.toml files

Keep only CLI flag --max-threads. Removed: - max_threads field from ForgeConfigFromScarb - Scarb config loading logic from main execution - Documentation from Scarb template - Unit tests for max_threads deserialization The number of threads can now only be set via CLI argument. Co-authored-by: cptartur <[email protected]>

Copilot · 2025-12-22T15:33:07Z

@copilot change the PR so that number of threads can only be set from the CLI and not in scarb.toml files

Done. Removed the Scarb.toml configuration option. The max_threads can now only be set via the --max-threads CLI flag. (4457e0d)

cptartur · 2025-12-23T16:42:40Z

crates/forge/src/lib.rs

+            let cores = if let Some(max_threads) = args.max_threads {
+                max_threads


@copilot Add a check that ensures that max_threads is less than or equal to available parallelism and fail in runtime if not.

Added validation check. The program now fails at runtime with an error message if --max-threads exceeds available parallelism. Also added a test to verify this behavior. (a3c1bc2)

cptartur · 2025-12-23T16:43:17Z

@copilot address failing clippy and rustfm checks.

…lism - Added runtime check that fails if --max-threads exceeds available CPU cores - Added e2e test to verify the validation works correctly - Error message clearly indicates the limit and what was provided Co-authored-by: cptartur <[email protected]>

- Clarified that validation is skipped when core detection fails - This allows users to override in edge cases where detection doesn't work Co-authored-by: cptartur <[email protected]>

cptartur · 2025-12-23T16:57:18Z

crates/forge/src/lib.rs

+            let cores = if let Some(max_threads) = args.max_threads {
+                // Validate that max_threads doesn't exceed available parallelism
+                // If we can't detect available cores, we skip validation and trust the user
+                if let Ok(available_cores) = available_parallelism() {


@copilot In case where user doesn't provide max-threads, we fail in case we cannot get available_paralleism. Let's fail here as well

Made the behavior consistent. Now both cases (with or without --max-threads) fail if available_parallelism() cannot detect CPU cores. Removed the fallback to 1 thread. (fc361a8)

- Fixed rustfmt: removed trailing whitespace and reformatted assert call - Fixed clippy: added #[allow(clippy::large_enum_variant)] to ForgeSubcommand enum - All linting checks now pass Co-authored-by: cptartur <[email protected]>

Copilot · 2025-12-23T17:07:12Z

@copilot address failing clippy and rustfm checks.

Fixed both clippy and rustfmt issues:

Removed trailing whitespace
Reformatted multi-line function call
Added #[allow(clippy::large_enum_variant)] to suppress pre-existing enum warning

All linting checks now pass. (c53c591)

- Now fails in both cases (with or without --max-threads) if available_parallelism() fails - Removed the fallback to 1 thread when detection fails - Added Context import for better error messages Co-authored-by: cptartur <[email protected]>

Initial plan

becd8cf

Copilot AI assigned Copilot and cptartur Dec 19, 2025

Copilot started work on behalf of cptartur December 19, 2025 14:48 View session

Copilot AI and others added 4 commits December 19, 2025 14:59

Add tests for max_threads configuration

b1f651b

- Added unit tests for max_threads deserialization in ForgeConfigFromScarb - Updated existing tests in combine_configs to include max_threads field Co-authored-by: cptartur <[email protected]>

Add e2e test for max_threads and update integration tests

2f93540

- Added e2e test to verify --max-threads CLI option works correctly - Updated integration tests to include max_threads field in ForgeConfigFromScarb Co-authored-by: cptartur <[email protected]>

Improve documentation for max_threads field

0f6623b

- Added clarifying comment that max_threads is read directly in main execution - This helps understand why the field isn't consumed by combine_configs Co-authored-by: cptartur <[email protected]>

Copilot AI changed the title ~~[WIP] Make test threads number configurable~~ Make test threads number configurable Dec 19, 2025

Copilot AI requested a review from cptartur December 19, 2025 15:14

Copilot finished work on behalf of cptartur December 19, 2025 15:14

cptartur reviewed Dec 22, 2025

View reviewed changes

Copilot started work on behalf of cptartur December 22, 2025 15:20 View session

Copilot AI changed the title ~~Make test threads number configurable~~ Make test threads number configurable via CLI Dec 22, 2025

Copilot AI requested a review from cptartur December 22, 2025 15:34

Copilot finished work on behalf of cptartur December 22, 2025 15:34

cptartur reviewed Dec 23, 2025

View reviewed changes

Copilot started work on behalf of cptartur December 23, 2025 16:43 View session

Copilot AI and others added 2 commits December 23, 2025 16:53

Add comment explaining validation skip behavior

17eddf1

- Clarified that validation is skipped when core detection fails - This allows users to override in edge cases where detection doesn't work Co-authored-by: cptartur <[email protected]>

Copilot AI requested a review from cptartur December 23, 2025 16:55

Copilot finished work on behalf of cptartur December 23, 2025 16:55

Copilot started work on behalf of cptartur December 23, 2025 16:55 View session

cptartur reviewed Dec 23, 2025

View reviewed changes

Fix clippy and rustfmt issues

c53c591

- Fixed rustfmt: removed trailing whitespace and reformatted assert call - Fixed clippy: added #[allow(clippy::large_enum_variant)] to ForgeSubcommand enum - All linting checks now pass Co-authored-by: cptartur <[email protected]>

Copilot finished work on behalf of cptartur December 23, 2025 17:08

Copilot AI requested a review from cptartur December 23, 2025 17:08

Copilot started work on behalf of cptartur December 23, 2025 17:08 View session

Copilot finished work on behalf of cptartur December 23, 2025 17:17

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

Make test threads number configurable via CLI #4055

Make test threads number configurable via CLI #4055

Uh oh!

Copilot AI commented Dec 19, 2025 •

edited

Loading

Uh oh!

cptartur left a comment

Uh oh!

Copilot AI commented Dec 22, 2025

Uh oh!

cptartur Dec 23, 2025

Uh oh!

Copilot AI Dec 23, 2025

Uh oh!

cptartur commented Dec 23, 2025

Uh oh!

cptartur Dec 23, 2025

Uh oh!

Copilot AI Dec 23, 2025

Uh oh!

Copilot AI commented Dec 23, 2025

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

		let cores = if let Some(max_threads) = args.max_threads {
		max_threads

Make test threads number configurable via CLI #4055

Are you sure you want to change the base?

Make test threads number configurable via CLI #4055

Uh oh!

Conversation

Copilot AI commented Dec 19, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Introduced changes

Checklist

Objective

Additional Context

Comments on the Issue (you are @copilot in this section)

Uh oh!

cptartur left a comment

Choose a reason for hiding this comment

Uh oh!

Copilot AI commented Dec 22, 2025

Uh oh!

cptartur Dec 23, 2025

Choose a reason for hiding this comment

Uh oh!

Copilot AI Dec 23, 2025

Choose a reason for hiding this comment

Uh oh!

cptartur commented Dec 23, 2025

Uh oh!

cptartur Dec 23, 2025

Choose a reason for hiding this comment

Uh oh!

Copilot AI Dec 23, 2025

Choose a reason for hiding this comment

Uh oh!

Copilot AI commented Dec 23, 2025

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

Copilot AI commented Dec 19, 2025 •

edited

Loading