Add custom error types for catchable ORM failures

Introduces an OrmError base class plus NotFoundError, TooManyRowsError,
and CreateFailedError so consumers can distinguish runtime row-count
failures from generic errors via instanceof. Each carries the modelName
and operation that caused it; TooManyRowsError also exposes rowCount.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: rsslldnphy

packages/orm/src/errors.ts

@@ -0,0 +1,59 @@
+export type SingleRowOperation = "findOne" | "updateOne" | "deleteOne";
+
+export class OrmError extends Error {
+    public override readonly name: string = "OrmError";
+
+    constructor(message: string) {
+        super(message);
+        Object.setPrototypeOf(this, OrmError.prototype);
+    }
+}
+
+export class NotFoundError extends OrmError {
+    public override readonly name = "NotFoundError";
+    public readonly modelName: string;
+    public readonly operation: SingleRowOperation;
+
+    constructor(
+        message: string,
+        details: { modelName: string; operation: SingleRowOperation },
+    ) {
+        super(message);
+        this.modelName = details.modelName;
+        this.operation = details.operation;
+        Object.setPrototypeOf(this, NotFoundError.prototype);
+    }
+}
+
+export class TooManyRowsError extends OrmError {
+    public override readonly name = "TooManyRowsError";
+    public readonly modelName: string;
+    public readonly operation: SingleRowOperation;
+    public readonly rowCount: number;
+
+    constructor(
+        message: string,
+        details: {
+            modelName: string;
+            operation: SingleRowOperation;
+            rowCount: number;
+        },
+    ) {
+        super(message);
+        this.modelName = details.modelName;
+        this.operation = details.operation;
+        this.rowCount = details.rowCount;
+        Object.setPrototypeOf(this, TooManyRowsError.prototype);
+    }
+}
+
+export class CreateFailedError extends OrmError {
+    public override readonly name = "CreateFailedError";
+    public readonly modelName: string;
+
+    constructor(message: string, details: { modelName: string }) {
+        super(message);
+        this.modelName = details.modelName;
+        Object.setPrototypeOf(this, CreateFailedError.prototype);
+    }
+}

packages/orm/src/index.ts

@@ -3,6 +3,14 @@ export * from "./operators.js";
 
 export { orm, type Orm } from "./orm.js";
 
+export {
+    CreateFailedError,
+    NotFoundError,
+    OrmError,
+    type SingleRowOperation,
+    TooManyRowsError,
+} from "./errors.js";
+
 export type {
     Config,
     FieldDefinition,

packages/orm/src/orm.createOne.ts

@@ -3,6 +3,7 @@ import { ModelDefinitions } from "@casekit/orm-schema";
 
 import { buildCreate } from "./builders/buildCreate.js";
 import { Connection } from "./connection.js";
+import { CreateFailedError } from "./errors.js";
 import { createToSql } from "./sql/createToSql.js";
 import { CreateOneParams } from "./types/CreateOneParams.js";
 import { Middleware } from "./types/Middleware.js";
@@ -31,7 +32,9 @@ export const createOne = async (
         const result = await tx.query(statement);
 
         if (!result.rowCount && query.onConflict?.do !== "nothing") {
-            throw new Error("createOne failed to create a row");
+            throw new CreateFailedError("createOne failed to create a row", {
+                modelName,
+            });
         }
 
         await tx.commit();

packages/orm/src/orm.deleteOne.ts

@@ -3,6 +3,7 @@ import { ModelDefinitions, OperatorDefinitions } from "@casekit/orm-schema";
 
 import { buildDelete } from "./builders/buildDelete.js";
 import { Connection } from "./connection.js";
+import { NotFoundError, TooManyRowsError } from "./errors.js";
 import { deleteToSql } from "./sql/deleteToSql.js";
 import { DeleteParams } from "./types/DeleteParams.js";
 import { Middleware } from "./types/Middleware.js";
@@ -28,9 +29,19 @@ export const deleteOne = async (
         const result = await tx.query(statement);
 
         if (!result.rowCount || result.rowCount === 0) {
-            throw new Error("Delete one failed to delete a row");
+            throw new NotFoundError("Delete one failed to delete a row", {
+                modelName,
+                operation: "deleteOne",
+            });
         } else if (result.rowCount > 1) {
-            throw new Error("Delete one would have deleted more than one row");
+            throw new TooManyRowsError(
+                "Delete one would have deleted more than one row",
+                {
+                    modelName,
+                    operation: "deleteOne",
+                    rowCount: result.rowCount,
+                },
+            );
         }
 
         await tx.commit();

packages/orm/src/orm.findOne.ts

@@ -2,6 +2,7 @@ import { NormalizedConfig } from "@casekit/orm-config";
 import { ModelDefinitions, OperatorDefinitions } from "@casekit/orm-schema";
 
 import { Connection } from "./connection.js";
+import { NotFoundError, TooManyRowsError } from "./errors.js";
 import { findMany } from "./orm.findMany.js";
 import { FindParams } from "./types/FindParams.js";
 import { Middleware } from "./types/Middleware.js";
@@ -18,10 +19,17 @@ export const findOne = async (
     const results = await findMany(config, conn, middleware, modelName, query);
 
     if (results.length === 0) {
-        throw new Error("Expected one row, but found none");
+        throw new NotFoundError("Expected one row, but found none", {
+            modelName,
+            operation: "findOne",
+        });
     }
     if (results.length > 1) {
-        throw new Error("Expected one row, but found more");
+        throw new TooManyRowsError("Expected one row, but found more", {
+            modelName,
+            operation: "findOne",
+            rowCount: results.length,
+        });
     }
     return results[0]!;
 };

packages/orm/src/orm.updateOne.ts

@@ -3,6 +3,7 @@ import { ModelDefinitions, OperatorDefinitions } from "@casekit/orm-schema";
 
 import { buildUpdate } from "./builders/buildUpdate.js";
 import { Connection } from "./connection.js";
+import { NotFoundError, TooManyRowsError } from "./errors.js";
 import { updateToSql } from "./sql/updateToSql.js";
 import { Middleware } from "./types/Middleware.js";
 import { UpdateParams } from "./types/UpdateParams.js";
@@ -32,9 +33,19 @@ export const updateOne = async (
         const result = await tx.query(statement);
 
         if (!result.rowCount || result.rowCount === 0) {
-            throw new Error("Update one failed to update a row");
+            throw new NotFoundError("Update one failed to update a row", {
+                modelName,
+                operation: "updateOne",
+            });
         } else if (result.rowCount > 1) {
-            throw new Error("Update one would have updated more than one row");
+            throw new TooManyRowsError(
+                "Update one would have updated more than one row",
+                {
+                    modelName,
+                    operation: "updateOne",
+                    rowCount: result.rowCount,
+                },
+            );
         }
 
         await tx.commit();