Fix: Correctly locate migrations folder for multi-file Prisma schema

[onozaty]

Summary

Fixes the bug where migrations were created in the wrong location when using multi-file Prisma schema configuration (issue #20).

Problem

When using --schema pointing to a folder (multi-file schema), the generator was creating migrations in ./schema/migrations/ instead of the correct location at the same level as the schema folder.

Root cause: The code was using path.dirname(schemaPath) which pointed to the schema folder itself, not its parent directory.

Solution

• Use config.outputDir (already correctly resolved by Prisma) instead of path.dirname(schemaPath)
• Remove unused schemaPath variable from generate function
• Rename baseDirPath parameter to migrationsDir for better clarity

Changes

• generator.ts: Updated to use config.outputDir for migration base path
• generator.test.ts:
  • Added multi-file-schema test case
  • Extended executeGenerate helper to handle multi-file schema
  • Extended getMigrationsDir helper to handle multi-file schema
• Test fixtures: Added multi-file-schema fixture with 3 schema files

Test Results

✅ All 55 tests passing
✅ New test case for multi-file schema configuration
✅ Backward compatible - single-file schema behavior unchanged

Test plan

• Run all existing tests
• Add new test for multi-file schema
• Verify migrations are created in correct location
• Verify backward compatibility with single-file schema

Fixes #20

[codecov]

Codecov Report

❌ Patch coverage is 0% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.41%. Comparing base (a9e8bc7) to head (4928584).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
src/generator.ts	0.00%	4 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #21   +/-   ##
=======================================
  Coverage   81.41%   81.41%           
=======================================
  Files           7        7           
  Lines         382      382           
  Branches       90       90           
=======================================
  Hits          311      311           
  Misses         71       71           

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[Copilot]

Pull Request Overview

This PR adds support for multi-file Prisma schemas by changing the migration directory resolution from using schemaPath to using the generator's outputDir configuration. This allows the generator to correctly place migrations relative to the schema location, whether it's a single file or a directory containing multiple schema files.

• Migration output directory now uses config.outputDir instead of path.dirname(schemaPath)
• Parameter renamed from baseDirPath to migrationsDir for better clarity
• Migration path construction simplified to directly use the migrations directory

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/generator.ts	Updated migration directory resolution to use config.outputDir and simplified path construction
src/generator.test.ts	Added test case for multi-file-schema support with appropriate directory handling
src/snapshots/generator.test.ts.snap	Added expected snapshots for multi-file-schema test outputs
src/fixtures/multi-file-schema/schema/schema.prisma	Created main schema configuration file for multi-file-schema test fixture
src/fixtures/multi-file-schema/schema/user.prisma	Created User model definition for multi-file-schema test fixture
src/fixtures/multi-file-schema/schema/post.prisma	Created Post model definition for multi-file-schema test fixture

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