fix: use dynamic import() to load Prisma client (fixes #22)

[tywenk]

Fixes #22.

Problem

The current implementation uses createRequire(import.meta.url) to synchronously require() the Prisma client at options.clientPath:

const require = createRequire(import.meta.url);
const { PrismaClient } = require(options.clientPath);

This is incompatible with Prisma 7's prisma-client generator, which outputs plain TypeScript (ESM) files that Node's native CJS require() cannot load. Under Vitest, those TS files are transformed by Vite — but the plugin's createRequire-based require() bypasses Vite's loader entirely, so resolution fails with either Cannot find module (when pointed at an extensionless path) or ERR_MODULE_NOT_FOUND on transitive imports (when pointed at the .ts file).

Fix

Switch to await import(options.clientPath):

• Under Vitest, clientPath pointed at the generated client.ts (or client.js) is handled by Vite's transform pipeline, which resolves TypeScript/ESM transparently.
• Under plain Node, any ESM-compatible specifier works — package names (e.g. @prisma/client), file:// URLs, or .js/.mjs paths.

Before dispatching the dynamic import, clientPath is normalized so that relative (./foo, ../foo) and absolute filesystem paths are resolved against the consuming project's process.cwd() and converted to file:// URLs. Bare module specifiers and pre-built file:// URLs pass through unchanged. This means users can pass a natural project-relative path — clientPath: "./src/generated/prisma/client.ts" — without manually constructing a file:// URL, and absolute paths work correctly on Windows (where ESM import() otherwise rejects bare drive paths).

createContext becomes async; the only caller (environment.setup in src/index.ts) is already async and just needs an await.

Tested

• Unit tests (11 tests across src/contest.test.ts and src/index.test.ts) all pass with 100% coverage preserved. Added a regression test that passes an absolute file:// URL as clientPath to cover the Prisma 7 path and the non-path-like branch of the resolver.

• Verified end-to-end against Prisma 7's prisma-client generator in a downstream project: 792 integration tests pass. With the new normalization, the config can be as simple as:

  // vitest.config.ts
  environmentOptions: {
    "prisma-postgres": {
      clientPath: "./src/generated/prisma/client.ts",
    },
  }

  A manually constructed file:// URL via pathToFileURL(path.resolve(...)) still works too.

  generator client {
    provider            = "prisma-client"
    output              = "../src/generated/prisma"
    runtime             = "nodejs"
    moduleFormat        = "esm"
    importFileExtension = "ts"
  }

Breaking change?

Technically yes — createContext now returns a Promise. No public users of createContext directly are documented in the README; consumers interact only through the Vitest environment, which is updated here. Happy to add a note to CHANGELOG if desired.

Summary by CodeRabbit

• Refactor
  • Context initialization is now asynchronous to support dynamic module loading and improve startup reliability.
• Bug Fixes
  • Improved handling of relative and absolute client module paths, including file:// URLs, for more predictable module resolution.
• Tests
  • Added coverage for absolute file:// client paths and full setup/teardown flow to prevent regressions.

[coderabbitai]

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📝 Walkthrough

Walkthrough

createContext now performs a dynamic ESM import for the Prisma client and is async; callers and tests were updated to await context creation and to accept file://-style clientPath specifiers.

Changes

Cohort / File(s)	Summary
Context loading (async ESM import) src/context.ts	Replaced CommonJS createRequire(...).require(clientPath) with await import(clientImportPath); normalize relative/absolute paths to file:// URLs; createContext is now async.
Initialization flow src/index.ts	Now awaits createContext(options) during environment setup so setup/teardown use the asynchronously created context.
Tests / helpers updated for async context & clientPath forms src/contest.test.ts, src/index.test.ts	makeContext updated to await createContext(...) and return appropriate Promise typed tuple; tests switched clientPath from ../test/prisma-client-stub.js to ./test/prisma-client-stub.js and added a case using an absolute file:// URL to verify import and full setup/teardown.

Sequence Diagram(s)

sequenceDiagram
  participant Test as Test Runner
  participant Env as Environment (index)
  participant Context as createContext
  participant Client as Prisma Client (module)
  participant Mock as PrismaPgMock

  Test->>Env: environment.setup(options with clientPath)
  Env->>Context: await createContext(options)
  Context->>Client: import(clientImportPath)
  Client-->>Context: PrismaClient class/module
  Context->>Mock: instantiate/initialize with connectionString
  Context-->>Env: context (with setup/teardown)
  Env-->>Test: setup complete

Loading

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

🐰 I hopped from require to import with glee,
No more stuck on .ts for me,
file:// paths and async cheer,
Context comes ready — setup’s near! 🥕

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	The PR successfully addresses all coding requirements from issue #22: replacing createRequire()/require() with dynamic import(), adding path normalization for file:// URLs, making createContext async, and including a test case for file:// URL paths.
Out of Scope Changes check	✅ Passed	All changes are directly related to issue #22 requirements: converting to dynamic import, normalizing paths, making createContext async, updating callers, and adding test coverage for file:// URLs.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title directly addresses the primary change: replacing synchronous CommonJS require() with dynamic ESM import() for loading the Prisma client, which is the core fix for issue #22.

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[coderabbitai]

Actionable comments posted: 1

🧹 Nitpick comments (1)

src/contest.test.ts (1)

23-24: Add a regression test case for file:// client paths to ensure Prisma 7/Vite compatibility.

The current test only covers a relative path. Adding a small test using pathToFileURL(...).href would verify that absolute file URLs work correctly as clientPath values.

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@src/contest.test.ts` around lines 23 - 24, Add a regression test that passes
an absolute file:// URL as clientPath to createContext to cover Prisma 7/Vite
compatibility; specifically, in the test file where createContext is invoked
with clientPath '../test/prisma-client-stub.js', add a new test that constructs
a file URL via pathToFileURL(somePath).href and supplies that string as
clientPath, then assert the same behaviors as the relative-path case so both
relative and file:// absolute clientPath values are validated.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@src/context.ts`:
- Line 31: The dynamic import using options.clientPath should first convert
relative ("./" or "../") and absolute filesystem paths to file:// URLs so they
resolve from the consuming project's CWD instead of src/context.ts; leave bare
module specifiers (like "@prisma/client") and existing file:// URLs unchanged.
Update the import site where you do const { PrismaClient } = await
import(options.clientPath); to: detect if options.clientPath starts with
"file://" or is a bare specifier (no path separators), otherwise resolve with
path.resolve(process.cwd(), options.clientPath) and convert to a URL via
url.pathToFileURL(...).href, then call import(resolvedPath). Ensure path and url
utilities are imported/available in the module.

---

Nitpick comments:
In `@src/contest.test.ts`:
- Around line 23-24: Add a regression test that passes an absolute file:// URL
as clientPath to createContext to cover Prisma 7/Vite compatibility;
specifically, in the test file where createContext is invoked with clientPath
'../test/prisma-client-stub.js', add a new test that constructs a file URL via
pathToFileURL(somePath).href and supplies that string as clientPath, then assert
the same behaviors as the relative-path case so both relative and file://
absolute clientPath values are validated.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

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📥 Commits

Reviewing files that changed from the base of the PR and between fc5b11e and 9ca03c4.

📒 Files selected for processing (3)

• src/contest.test.ts
• src/context.ts
• src/index.ts