Fix PgClient makeClient missing error event handler

.changeset/pg-client-connect-error-handler.md

@@ -0,0 +1,5 @@
+---
+"@effect/sql-pg": patch
+---
+
+Prevent unhandled `pg` client error events while `PgClient.makeClient` is connecting.

packages/sql/pg/src/PgClient.ts

@@ -219,8 +219,9 @@ export const makeClient = (
      */
     readonly acquireForStream?: boolean | undefined
   }
-): Effect.Effect<PgClient, SqlError, Scope.Scope | Reactivity.Reactivity> =>
-  fromClient({
+): Effect.Effect<PgClient, SqlError, Scope.Scope | Reactivity.Reactivity> => {
+  function onError() {}
+  return fromClient({
     ...options,
     acquire: Effect.acquireRelease(
       Effect.tryPromise({
@@ -237,13 +238,17 @@ export const makeClient = (
             application_name: options.applicationName ?? "@effect/sql-pg",
             types: options.types
           })
+          client.on("error", onError)
           await client.connect()
           return client
         },
         catch: (cause) => new SqlError({ reason: classifyError(cause, "PgClient: Failed to connect", "connect") })
       }),
       (client) =>
-        Effect.promise(() => client.end()).pipe(
+        Effect.promise(() => {
+          client.off("error", onError)
+          return client.end()
+        }).pipe(
           Effect.timeoutOption(1000)
         ),
       { interruptible: true }
@@ -264,6 +269,7 @@ export const makeClient = (
     ),
     acquireForStream: options.acquireForStream ?? false
   })
+}
 
 /**
  * Builds a PostgreSQL client from a scoped `pg` pool acquisition effect, deriving transaction, streaming, and LISTEN/NOTIFY support from that pool.

packages/sql/pg/test/Client.integration.test.ts

@@ -5,7 +5,9 @@ import { TestClock } from "effect/testing"
 import * as Reactivity from "effect/unstable/reactivity/Reactivity"
 import { SqlClient } from "effect/unstable/sql"
 import * as Statement from "effect/unstable/sql/Statement"
+import * as Pg from "pg"
 import { parse as parsePgConnectionString } from "pg-connection-string"
+import { vi } from "vitest"
 import { PgContainer } from "./utils.ts"
 
 const compilerTransform = PgClient.makeCompiler(String.camelToSnake)
@@ -295,6 +297,35 @@ it.layer(PgContainer.layerMakeClient, { timeout: "30 seconds" })("PgClient.makeC
     }))
 })
 
+it.effect("PgClient.makeClient handles errors emitted while connecting", () =>
+  Effect.acquireUseRelease(
+    Effect.sync(() => ({
+      connect: vi.spyOn(Pg.Client.prototype, "connect").mockImplementation(function(this: Pg.Client) {
+        return new Promise<void>((resolve, reject) => {
+          queueMicrotask(() => {
+            try {
+              this.emit("error", new Error("connection failed"))
+              resolve()
+            } catch (cause) {
+              reject(cause)
+            }
+          })
+        })
+      }),
+      end: vi.spyOn(Pg.Client.prototype, "end").mockResolvedValue(undefined)
+    })),
+    () =>
+      PgClient.makeClient({ host: "localhost" }).pipe(
+        Effect.scoped,
+        Effect.provide(Reactivity.layer)
+      ),
+    ({ connect, end }) =>
+      Effect.sync(() => {
+        connect.mockRestore()
+        end.mockRestore()
+      })
+  ))
+
 it.layer(PgContainer.layerClientWithTransforms, { timeout: "30 seconds" })("PgClient transforms", (it) => {
   it.effect("insert helper", () =>
     Effect.gen(function*() {