fix: emit type-only imports in hono handlers and mcp http-client

[ErfanBagheri404]

Fixes #3933, fixes #3934. Part of #3931.

Summary

Two generators emitted value imports for symbols their output only uses as types, tripping consistent-type-imports in every generated hono/mcp file.

hono (packages/hono/src/index.ts, packages/hono/src/handler-merge.ts, packages/hono/src/zValidator.ts):

• Handler-file context imports are now import type { ...Context } from '...context' — context identifiers only appear in the typed handler callback (async (c: XContext) => {}). Both the fresh-file emission and the handler-merge reconciler (via a new typeOnly flag on renderImport) are covered.
• The zValidator template's import * as v3 from 'zod/v3' / import * as v4 from 'zod/v4/core' are now import type * — every usage is a type position (schema as v3.ZodType is an assertion, the rest are conditional types).

One deliberate deviation from the issue: the zod schema imports (ShowPetWithOwnerParams, etc.) stay value imports. zValidator('param', ShowPetWithOwnerParams) passes them to the validator at runtime, so making them type-only would break the generated code. The lint warnings on those lines were false positives from the rule's perspective of the file, but the emitted code compiles and runs correctly either way — the fix targets only genuinely type-only symbols.

mcp (packages/mcp/src/index.ts):

• The http-client's schema import (line ~562, importImplementation) is now import type — Pets, ListPetsParams, CreatePetsBody, etc. are referenced only in type aliases and function signatures.
• The server file's schemas import (importSchemasImplementation) is now import type — body/param type names used only as handler parameter types.

Verification

• vp lint --no-ignore tests/__snapshots__/hono tests/__snapshots__/mcp — 0 consistent-type-imports warnings (previously 60 + 9)
• Snapshot/samples regenerated: 59 snapshot files + 14 sample files updated, all diffs are exactly the import → import type transitions
• hono package tests: 59/59 pass

Scope note

#3935 (angular QueryClient) is intentionally not included. QueryClient is imported with values: true because the angular mutation invalidation path emits const queryClient = inject(QueryClient); — a genuine value use (see samples/angular-query/src/api/endpoints/pets/pets.ts). The static dependency list can't express "value only when invalidation is used", so flipping the flag would break real output. That one needs conditional emission, which is a design decision rather than a mechanical fix.

Summary by CodeRabbit

• Bug Fixes
  • Generated Hono and MCP code now emits type-only imports for context, schema, and validation types.
  • Updated generated samples and handlers to use type-only imports consistently.
• Refactor
  • Import generation now distinguishes type-only imports from runtime imports.
  • Type-only imports are excluded from compiled runtime code, with no runtime behavior changes.

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📥 Commits

Reviewing files that changed from the base of the PR and between f772b49 and ccc9191.

📒 Files selected for processing (8)

• samples/hono/hono-with-fetch-client/hono-app/src/handlers/createPets.ts
• samples/hono/hono-with-fetch-client/hono-app/src/handlers/listPets.ts
• samples/hono/hono-with-fetch-client/hono-app/src/handlers/showPetById.ts
• samples/hono/hono-with-fetch-client/hono-app/src/handlers/updatePets.ts
• samples/hono/hono-with-zod/src/handlers/createPets.ts
• samples/hono/hono-with-zod/src/handlers/listPets.ts
• samples/hono/hono-with-zod/src/handlers/showPetById.ts
• samples/hono/hono-with-zod/src/handlers/updatePets.ts

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📝 Walkthrough

Walkthrough

The generators now emit import type for context, schema, parameter, response, and Zod namespace imports used only in type positions. Hono import reconciliation preserves this mode for inserted and rewritten imports. MCP and sample outputs use the updated form.

Changes

Type-only import generation

Layer / File(s)	Summary
Import rendering and reconciliation packages/hono/src/handler-merge.ts, packages/hono/src/handler-merge.test.ts	Hono import rendering and reconciliation now support and preserve the typeOnly option. Existing regular imports are rewritten when a type-only import is required. Tests expect type-only context imports.
Hono generated imports packages/hono/src/index.ts, packages/hono/src/zValidator.ts, samples/hono/...	Generated context imports and Zod namespace imports now use import type. Hono samples use the same import form.
MCP generated imports packages/mcp/src/index.ts, samples/mcp/...	Generated schema, handler, and HTTP client imports now use import type.

Estimated code review effort: 2 (Simple) | ~10 minutes

Merge Risk: ⚪ Minimal · up to ccc91

The generators now remove runtime imports only for symbols used exclusively as TypeScript types, reducing lint warnings without changing generated runtime behavior. No current merge-blocking risk remains.

Sequence Diagram(s)

sequenceDiagram
  participant HonoGenerator
  participant ImportReconciler
  participant GeneratedFile
  HonoGenerator->>ImportReconciler: request type-only context import
  ImportReconciler->>ImportReconciler: compare import mode
  ImportReconciler->>GeneratedFile: insert or rewrite import type declaration

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🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Linked Issues check	⚠️ Warning	The MCP requirements are addressed, and Hono context and Zod namespace imports are updated. However, issue #3933 also requires type-only imports for Hono handler schema types, while the pull request e…	Update the Hono generator and regenerated outputs to emit import type for schema symbols used only in type positions. Keep schema imports as value imports only when runtime usage requires them. Re-run the relevant lint checks and tests.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Out of Scope Changes check	✅ Passed	The changes are related to type-only import generation, regenerated samples, and test expectations for the linked Hono and MCP objectives. No unrelated code changes are evident.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 2…
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the main change: emitting type-only imports in Hono handlers and MCP HTTP clients.

Full details: Linked Issues check

Explanation

The MCP requirements are addressed, and Hono context and Zod namespace imports are updated. However, issue #3933 also requires type-only imports for Hono handler schema types, while the pull request explicitly leaves those imports as value imports.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

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Actionable comments posted: 1

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Inline comments:
In `@packages/hono/src/handler-merge.ts`:
- Line 286: Update the existing-import fast path in the context reconciliation
logic to include typeOnly when comparing imports, so a type-only request does
not match an existing regular import. Preserve name and module matching while
ensuring the resulting import becomes import type when typeOnly is true.

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📥 Commits

Reviewing files that changed from the base of the PR and between 43dd303 and 457416b.

⛔ Files ignored due to path filters (65)

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📒 Files selected for processing (12)

• packages/hono/src/handler-merge.ts
• packages/hono/src/index.ts
• packages/hono/src/zValidator.ts
• packages/mcp/src/index.ts
• samples/hono/composite-routes-with-tags-split/src/endpoints/pets/pets.handlers.ts
• samples/hono/composite-routes-with-tags-split/src/endpoints/validator.ts
• samples/hono/hono-with-fetch-client/hono-app/src/petstore.validator.ts
• samples/hono/hono-with-zod/src/petstore.validator.ts
• samples/mcp/custom-server/src/handlers.ts
• samples/mcp/custom-server/src/http-client.ts
• samples/mcp/petstore/src/handlers.ts
• samples/mcp/petstore/src/http-client.ts

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