fix(core): preserve workflow input after finish

[VihaanAgarwal]

What this fixes

WorkflowStateManager.finish() reassigned the stored input to the current data:

finish() {
  assertCanMutate(this.#state);
  this.#input = this.#state.data as DATA;   // removed
  ...
}

WorkflowState.input is documented as the initial input to the workflow, and update() deliberately preserves it across the run. But finish() overwrote it with the final data, so reading state.input after a workflow completed returned the final output instead of the original input.

Repro

const sm = createWorkflowStateManager();
sm.start({ value: "original" });
sm.update({ data: { value: "final" } });
sm.finish();
sm.state.input; // { value: "final" }  — expected { value: "original" }

Fix

Remove the reassignment in finish(). The input is set once in start() and now stays put through completion; state.data still reflects the final value. Added a regression test, and the full workflow suite (164 tests) stays green.

---

Summary by cubic

In @voltagent/core, fix WorkflowStateManager.finish() overwriting state.input with the final data, so completed workflows now preserve their original input. Removed the reassignment and added a regression test; state.data still reflects the final value.

^{Written for commit 79496a1. Summary will update on new commits.}

Summary by CodeRabbit

• Bug Fixes
  • Fixed workflow completion so the original input remains preserved after a run finishes.
  • Ensured the final workflow state still reflects the completed output separately from the initial input.
• Tests
  • Added coverage verifying that completed workflows keep the starting input unchanged while updating the final data value.

[changeset-bot]

🦋 Changeset detected

Latest commit: 79496a1

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

This PR includes changesets to release 1 package

Name	Type
@voltagent/core	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

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 1c2a67c2-ca6c-4e01-8f6d-b4f32cdda8d9

📥 Commits

Reviewing files that changed from the base of the PR and between 17732a3 and 79496a1.

📒 Files selected for processing (3)

• .changeset/workflow-input-preserved-after-finish.md
• packages/core/src/workflow/internal/state.spec.ts
• packages/core/src/workflow/internal/state.ts

💤 Files with no reviewable changes (1)

• packages/core/src/workflow/internal/state.ts

---

📝 Walkthrough

Walkthrough

Removes a single line from WorkflowStateManagerInternal.finish() that overwrote #input with the current #state.data. A test is added to verify state.input retains the original value while state.data holds the final result. A changeset documents the patch.

Changes

Workflow state input preservation

Layer / File(s)	Summary
finish() fix, regression test, and changeset packages/core/src/workflow/internal/state.ts, packages/core/src/workflow/internal/state.spec.ts, .changeset/workflow-input-preserved-after-finish.md	Removes the assignment #input = #state.data`` from finish() so the original input is retained; adds a test asserting `state.input` stays as the initial value while `state.data` reflects the final update; adds a patch changeset.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

Possibly related PRs

• VoltAgent/voltagent#1048: Resume logic reads workflowState.input from storage, which was affected by the same finish() overwrite this PR corrects.

Suggested reviewers

• omeraplak

🐇 A line removed, a value saved,
state.input no longer misbehaved.
The finish line won't steal your start,
each field now plays its proper part.
Hop hop hooray for clean-cut state! 🎉

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the main fix: preserving workflow input after finish.
Description check	✅ Passed	The description covers the bug, repro, fix, and testing, though it does not fully follow the template headings and checklist items.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[cubic-dev-ai]

No issues found across 3 files

_{Re-trigger cubic}