Improve ai error handling (#4180)

* Introduce a result type

* Update AI error handling to use the result type

* Handle ollama json parse error

* Migrate using Error as the type that represents errors

* Remove now useless condition

* asdfasdf

* Use andThen

* Correct unit tests

app/src/lib/ai/anthropicClient.ts

@@ -1,8 +1,12 @@
 import { SHORT_DEFAULT_COMMIT_TEMPLATE, SHORT_DEFAULT_BRANCH_TEMPLATE } from '$lib/ai/prompts';
+import { type AIClient, type AnthropicModelName, type Prompt } from '$lib/ai/types';
+import { buildFailureFromAny, ok, type Result } from '$lib/result';
 import { fetch, Body } from '@tauri-apps/api/http';
-import type { AIClient, AnthropicModelName, Prompt } from '$lib/ai/types';
 
-type AnthropicAPIResponse = { content: { text: string }[] };
+type AnthropicAPIResponse = {
+	content: { text: string }[];
+	error: { type: string; message: string };
+};
 
 export class AnthropicAIClient implements AIClient {
 	defaultCommitTemplate = SHORT_DEFAULT_COMMIT_TEMPLATE;
@@ -13,7 +17,7 @@ export class AnthropicAIClient implements AIClient {
 		private modelName: AnthropicModelName
 	) {}
 
-	async evaluate(prompt: Prompt) {
+	async evaluate(prompt: Prompt): Promise<Result<string, Error>> {
 		const body = Body.json({
 			messages: prompt,
 			max_tokens: 1024,
@@ -30,6 +34,12 @@ export class AnthropicAIClient implements AIClient {
 			body
 		});
 
-		return response.data.content[0].text;
+		if (response.ok && response.data?.content?.[0]?.text) {
+			return ok(response.data.content[0].text);
+		} else {
+			return buildFailureFromAny(
+				`Anthropic returned error code ${response.status} ${response.data?.error?.message}`
+			);
+		}
 	}
 }

app/src/lib/ai/butlerClient.ts

@@ -1,4 +1,5 @@
 import { SHORT_DEFAULT_BRANCH_TEMPLATE, SHORT_DEFAULT_COMMIT_TEMPLATE } from '$lib/ai/prompts';
+import { map, type Result } from '$lib/result';
 import type { AIClient, ModelKind, Prompt } from '$lib/ai/types';
 import type { HttpClient } from '$lib/backend/httpClient';
 
@@ -12,16 +13,19 @@ export class ButlerAIClient implements AIClient {
 		private modelKind: ModelKind
 	) {}
 
-	async evaluate(prompt: Prompt) {
-		const response = await this.cloud.post<{ message: string }>('evaluate_prompt/predict.json', {
-			body: {
-				messages: prompt,
-				max_tokens: 400,
-				model_kind: this.modelKind
-			},
-			token: this.userToken
-		});
+	async evaluate(prompt: Prompt): Promise<Result<string, Error>> {
+		const response = await this.cloud.postSafe<{ message: string }>(
+			'evaluate_prompt/predict.json',
+			{
+				body: {
+					messages: prompt,
+					max_tokens: 400,
+					model_kind: this.modelKind
+				},
+				token: this.userToken
+			}
+		);
 
-		return response.message;
+		return map(response, ({ message }) => message);
 	}
 }

app/src/lib/ai/ollamaClient.ts

@@ -1,5 +1,6 @@
 import { LONG_DEFAULT_BRANCH_TEMPLATE, LONG_DEFAULT_COMMIT_TEMPLATE } from '$lib/ai/prompts';
 import { MessageRole, type PromptMessage, type AIClient, type Prompt } from '$lib/ai/types';
+import { andThen, buildFailureFromAny, ok, wrap, wrapAsync, type Result } from '$lib/result';
 import { isNonEmptyObject } from '$lib/utils/typeguards';
 import { fetch, Body, Response } from '@tauri-apps/api/http';
 
@@ -81,15 +82,22 @@ export class OllamaClient implements AIClient {
 		private modelName: string
 	) {}
 
-	async evaluate(prompt: Prompt) {
+	async evaluate(prompt: Prompt): Promise<Result<string, Error>> {
 		const messages = this.formatPrompt(prompt);
-		const response = await this.chat(messages);
-		const rawResponse = JSON.parse(response.message.content);
-		if (!isOllamaChatMessageFormat(rawResponse)) {
-			throw new Error('Invalid response: ' + response.message.content);
-		}
 
-		return rawResponse.result;
+		const responseResult = await this.chat(messages);
+
+		return andThen(responseResult, (response) => {
+			const rawResponseResult = wrap<unknown, Error>(() => JSON.parse(response.message.content));
+
+			return andThen(rawResponseResult, (rawResponse) => {
+				if (!isOllamaChatMessageFormat(rawResponse)) {
+					return buildFailureFromAny('Invalid response: ' + response.message.content);
+				}
+
+				return ok(rawResponse.result);
+			});
+		});
 	}
 
 	/**
@@ -124,17 +132,19 @@ ${JSON.stringify(OLLAMA_CHAT_MESSAGE_FORMAT_SCHEMA, null, 2)}`
 	 * @param request - The OllamaChatRequest object containing the request details.
 	 * @returns A Promise that resolves to the Response object.
 	 */
-	private async fetchChat(request: OllamaChatRequest): Promise<Response<any>> {
+	private async fetchChat(request: OllamaChatRequest): Promise<Result<Response<any>, Error>> {
 		const url = new URL(OllamaAPEndpoint.Chat, this.endpoint);
 		const body = Body.json(request);
-		const result = await fetch(url.toString(), {
-			method: 'POST',
-			headers: {
-				'Content-Type': 'application/json'
-			},
-			body
-		});
-		return result;
+		return await wrapAsync(
+			async () =>
+				await fetch(url.toString(), {
+					method: 'POST',
+					headers: {
+						'Content-Type': 'application/json'
+					},
+					body
+				})
+		);
 	}
 
 	/**
@@ -142,13 +152,12 @@ ${JSON.stringify(OLLAMA_CHAT_MESSAGE_FORMAT_SCHEMA, null, 2)}`
 	 *
 	 * @param messages - An array of LLMChatMessage objects representing the chat messages.
 	 * @param options - Optional LLMRequestOptions object for specifying additional options.
-	 * @throws Error if the response is invalid.
 	 * @returns A Promise that resolves to an LLMResponse object representing the response from the LLM model.
 	 */
 	private async chat(
 		messages: Prompt,
 		options?: OllamaRequestOptions
-	): Promise<OllamaChatResponse> {
+	): Promise<Result<OllamaChatResponse, Error>> {
 		const result = await this.fetchChat({
 			model: this.modelName,
 			stream: false,
@@ -157,10 +166,12 @@ ${JSON.stringify(OLLAMA_CHAT_MESSAGE_FORMAT_SCHEMA, null, 2)}`
 			format: 'json'
 		});
 
-		if (!isOllamaChatResponse(result.data)) {
-			throw new Error('Invalid response\n' + JSON.stringify(result.data));
-		}
+		return andThen(result, (result) => {
+			if (!isOllamaChatResponse(result.data)) {
+				return buildFailureFromAny('Invalid response\n' + JSON.stringify(result.data));
+			}
 
-		return result.data;
+			return ok(result.data);
+		});
 	}
 }

app/src/lib/ai/openAIClient.ts

@@ -1,6 +1,8 @@
 import { SHORT_DEFAULT_BRANCH_TEMPLATE, SHORT_DEFAULT_COMMIT_TEMPLATE } from '$lib/ai/prompts';
+import { andThen, buildFailureFromAny, ok, wrapAsync, type Result } from '$lib/result';
 import type { OpenAIModelName, Prompt, AIClient } from '$lib/ai/types';
 import type OpenAI from 'openai';
+import type { ChatCompletion } from 'openai/resources/index.mjs';
 
 export class OpenAIClient implements AIClient {
 	defaultCommitTemplate = SHORT_DEFAULT_COMMIT_TEMPLATE;
@@ -11,13 +13,21 @@ export class OpenAIClient implements AIClient {
 		private openAI: OpenAI
 	) {}
 
-	async evaluate(prompt: Prompt) {
-		const response = await this.openAI.chat.completions.create({
-			messages: prompt,
-			model: this.modelName,
-			max_tokens: 400
+	async evaluate(prompt: Prompt): Promise<Result<string, Error>> {
+		const responseResult = await wrapAsync<ChatCompletion, Error>(async () => {
+			return await this.openAI.chat.completions.create({
+				messages: prompt,
+				model: this.modelName,
+				max_tokens: 400
+			});
 		});
 
-		return response.choices[0].message.content || '';
+		return andThen(responseResult, (response) => {
+			if (response.choices[0]?.message.content) {
+				return ok(response.choices[0]?.message.content);
+			} else {
+				return buildFailureFromAny('Open AI generated an empty message');
+			}
+		});
 	}
 }

app/src/lib/ai/service.test.ts

@@ -11,7 +11,7 @@ import {
 	type Prompt
 } from '$lib/ai/types';
 import { HttpClient } from '$lib/backend/httpClient';
-import * as toasts from '$lib/utils/toasts';
+import { buildFailureFromAny, ok, unwrap, type Result } from '$lib/result';
 import { Hunk } from '$lib/vbranches/types';
 import { plainToInstance } from 'class-transformer';
 import { expect, test, describe, vi } from 'vitest';
@@ -56,8 +56,8 @@ class DummyAIClient implements AIClient {
 	defaultBranchTemplate = SHORT_DEFAULT_BRANCH_TEMPLATE;
 	constructor(private response = 'lorem ipsum') {}
 
-	async evaluate(_prompt: Prompt) {
-		return this.response;
+	async evaluate(_prompt: Prompt): Promise<Result<string, Error>> {
+		return ok(this.response);
 	}
 }
 
@@ -116,16 +116,14 @@ describe.concurrent('AIService', () => {
 		test('With default configuration, When a user token is provided. It returns ButlerAIClient', async () => {
 			const aiService = buildDefaultAIService();
 
-			expect(await aiService.buildClient('token')).toBeInstanceOf(ButlerAIClient);
+			expect(unwrap(await aiService.buildClient('token'))).toBeInstanceOf(ButlerAIClient);
 		});
 
 		test('With default configuration, When a user is undefined. It returns undefined', async () => {
-			const toastErrorSpy = vi.spyOn(toasts, 'error');
 			const aiService = buildDefaultAIService();
 
-			expect(await aiService.buildClient()).toBe(undefined);
-			expect(toastErrorSpy).toHaveBeenLastCalledWith(
-				"When using GitButler's API to summarize code, you must be logged in"
+			expect(await aiService.buildClient()).toStrictEqual(
+				buildFailureFromAny("When using GitButler's API to summarize code, you must be logged in")
 			);
 		});
 
@@ -137,11 +135,10 @@ describe.concurrent('AIService', () => {
 			});
 			const aiService = new AIService(gitConfig, cloud);
 
-			expect(await aiService.buildClient()).toBeInstanceOf(OpenAIClient);
+			expect(unwrap(await aiService.buildClient())).toBeInstanceOf(OpenAIClient);
 		});
 
 		test('When token is bring your own, When a openAI token is blank. It returns undefined', async () => {
-			const toastErrorSpy = vi.spyOn(toasts, 'error');
 			const gitConfig = new DummyGitConfigService({
 				...defaultGitConfig,
 				[GitAIConfigKey.OpenAIKeyOption]: KeyOption.BringYourOwn,
@@ -149,9 +146,10 @@ describe.concurrent('AIService', () => {
 			});
 			const aiService = new AIService(gitConfig, cloud);
 
-			expect(await aiService.buildClient()).toBe(undefined);
-			expect(toastErrorSpy).toHaveBeenLastCalledWith(
-				'When using OpenAI in a bring your own key configuration, you must provide a valid token'
+			expect(await aiService.buildClient()).toStrictEqual(
+				buildFailureFromAny(
+					'When using OpenAI in a bring your own key configuration, you must provide a valid token'
+				)
 			);
 		});
 
@@ -164,11 +162,10 @@ describe.concurrent('AIService', () => {
 			});
 			const aiService = new AIService(gitConfig, cloud);
 
-			expect(await aiService.buildClient()).toBeInstanceOf(AnthropicAIClient);
+			expect(unwrap(await aiService.buildClient())).toBeInstanceOf(AnthropicAIClient);
 		});
 
 		test('When ai provider is Anthropic, When token is bring your own, When an anthropic token is blank. It returns undefined', async () => {
-			const toastErrorSpy = vi.spyOn(toasts, 'error');
 			const gitConfig = new DummyGitConfigService({
 				...defaultGitConfig,
 				[GitAIConfigKey.ModelProvider]: ModelKind.Anthropic,
@@ -177,9 +174,10 @@ describe.concurrent('AIService', () => {
 			});
 			const aiService = new AIService(gitConfig, cloud);
 
-			expect(await aiService.buildClient()).toBe(undefined);
-			expect(toastErrorSpy).toHaveBeenLastCalledWith(
-				'When using Anthropic in a bring your own key configuration, you must provide a valid token'
+			expect(await aiService.buildClient()).toStrictEqual(
+				buildFailureFromAny(
+					'When using Anthropic in a bring your own key configuration, you must provide a valid token'
+				)
 			);
 		});
 	});
@@ -188,9 +186,13 @@ describe.concurrent('AIService', () => {
 		test('When buildModel returns undefined, it returns undefined', async () => {
 			const aiService = buildDefaultAIService();
 
-			vi.spyOn(aiService, 'buildClient').mockReturnValue((async () => undefined)());
+			vi.spyOn(aiService, 'buildClient').mockReturnValue(
+				(async () => buildFailureFromAny('Failed to build'))()
+			);
 
-			expect(await aiService.summarizeCommit({ hunks: exampleHunks })).toBe(undefined);
+			expect(await aiService.summarizeCommit({ hunks: exampleHunks })).toStrictEqual(
+				buildFailureFromAny('Failed to build')
+			);
 		});
 
 		test('When the AI returns a single line commit message, it returns it unchanged', async () => {
@@ -199,10 +201,12 @@ describe.concurrent('AIService', () => {
 			const clientResponse = 'single line commit';
 
 			vi.spyOn(aiService, 'buildClient').mockReturnValue(
-				(async () => new DummyAIClient(clientResponse))()
+				(async () => ok<AIClient, Error>(new DummyAIClient(clientResponse)))()
 			);
 
-			expect(await aiService.summarizeCommit({ hunks: exampleHunks })).toBe('single line commit');
+			expect(await aiService.summarizeCommit({ hunks: exampleHunks })).toStrictEqual(
+				ok('single line commit')
+			);
 		});
 
 		test('When the AI returns a title and body that is split by a single new line, it replaces it with two', async () => {
@@ -211,10 +215,12 @@ describe.concurrent('AIService', () => {
 			const clientResponse = 'one\nnew line';
 
 			vi.spyOn(aiService, 'buildClient').mockReturnValue(
-				(async () => new DummyAIClient(clientResponse))()
+				(async () => ok<AIClient, Error>(new DummyAIClient(clientResponse)))()
 			);
 
-			expect(await aiService.summarizeCommit({ hunks: exampleHunks })).toBe('one\n\nnew line');
+			expect(await aiService.summarizeCommit({ hunks: exampleHunks })).toStrictEqual(
+				ok('one\n\nnew line')
+			);
 		});
 
 		test('When the commit is in brief mode, When the AI returns a title and body, it takes just the title', async () => {
@@ -223,12 +229,12 @@ describe.concurrent('AIService', () => {
 			const clientResponse = 'one\nnew line';
 
 			vi.spyOn(aiService, 'buildClient').mockReturnValue(
-				(async () => new DummyAIClient(clientResponse))()
+				(async () => ok<AIClient, Error>(new DummyAIClient(clientResponse)))()
 			);
 
-			expect(await aiService.summarizeCommit({ hunks: exampleHunks, useBriefStyle: true })).toBe(
-				'one'
-			);
+			expect(
+				await aiService.summarizeCommit({ hunks: exampleHunks, useBriefStyle: true })
+			).toStrictEqual(ok('one'));
 		});
 	});
 
@@ -236,9 +242,13 @@ describe.concurrent('AIService', () => {
 		test('When buildModel returns undefined, it returns undefined', async () => {
 			const aiService = buildDefaultAIService();
 
-			vi.spyOn(aiService, 'buildClient').mockReturnValue((async () => undefined)());
+			vi.spyOn(aiService, 'buildClient').mockReturnValue(
+				(async () => buildFailureFromAny('Failed to build client'))()
+			);
 
-			expect(await aiService.summarizeBranch({ hunks: exampleHunks })).toBe(undefined);
+			expect(await aiService.summarizeBranch({ hunks: exampleHunks })).toStrictEqual(
+				buildFailureFromAny('Failed to build client')
+			);
 		});
 
 		test('When the AI client returns a string with spaces, it replaces them with hypens', async () => {
@@ -247,10 +257,12 @@ describe.concurrent('AIService', () => {
 			const clientResponse = 'with spaces included';
 
 			vi.spyOn(aiService, 'buildClient').mockReturnValue(
-				(async () => new DummyAIClient(clientResponse))()
+				(async () => ok<AIClient, Error>(new DummyAIClient(clientResponse)))()
 			);
 
-			expect(await aiService.summarizeBranch({ hunks: exampleHunks })).toBe('with-spaces-included');
+			expect(await aiService.summarizeBranch({ hunks: exampleHunks })).toStrictEqual(
+				ok('with-spaces-included')
+			);
 		});
 
 		test('When the AI client returns multiple lines, it replaces them with hypens', async () => {
@@ -259,11 +271,11 @@ describe.concurrent('AIService', () => {
 			const clientResponse = 'with\nnew\nlines\nincluded';
 
 			vi.spyOn(aiService, 'buildClient').mockReturnValue(
-				(async () => new DummyAIClient(clientResponse))()
+				(async () => ok<AIClient, Error>(new DummyAIClient(clientResponse)))()
 			);
 
-			expect(await aiService.summarizeBranch({ hunks: exampleHunks })).toBe(
-				'with-new-lines-included'
+			expect(await aiService.summarizeBranch({ hunks: exampleHunks })).toStrictEqual(
+				ok('with-new-lines-included')
 			);
 		});
 
@@ -273,11 +285,11 @@ describe.concurrent('AIService', () => {
 			const clientResponse = 'with\nnew lines\nincluded';
 
 			vi.spyOn(aiService, 'buildClient').mockReturnValue(
-				(async () => new DummyAIClient(clientResponse))()
+				(async () => ok<AIClient, Error>(new DummyAIClient(clientResponse)))()
 			);
 
-			expect(await aiService.summarizeBranch({ hunks: exampleHunks })).toBe(
-				'with-new-lines-included'
+			expect(await aiService.summarizeBranch({ hunks: exampleHunks })).toStrictEqual(
+				ok('with-new-lines-included')
 			);
 		});
 	});

app/src/lib/ai/service.ts

@@ -14,8 +14,8 @@ import {
 	MessageRole,
 	type Prompt
 } from '$lib/ai/types';
+import { buildFailureFromAny, isFailure, ok, type Result } from '$lib/result';
 import { splitMessage } from '$lib/utils/commitMessage';
-import * as toasts from '$lib/utils/toasts';
 import OpenAI from 'openai';
 import type { GitConfigService } from '$lib/backend/gitConfigService';
 import type { HttpClient } from '$lib/backend/httpClient';
@@ -189,21 +189,22 @@ export class AIService {
 	// This optionally returns a summarizer. There are a few conditions for how this may occur
 	// Firstly, if the user has opted to use the GB API and isn't logged in, it will return undefined
 	// Secondly, if the user has opted to bring their own key but hasn't provided one, it will return undefined
-	async buildClient(userToken?: string): Promise<undefined | AIClient> {
+	async buildClient(userToken?: string): Promise<Result<AIClient, Error>> {
 		const modelKind = await this.getModelKind();
 
 		if (await this.usingGitButlerAPI()) {
 			if (!userToken) {
-				toasts.error("When using GitButler's API to summarize code, you must be logged in");
-				return;
+				return buildFailureFromAny(
+					"When using GitButler's API to summarize code, you must be logged in"
+				);
 			}
-			return new ButlerAIClient(this.cloud, userToken, modelKind);
+			return ok(new ButlerAIClient(this.cloud, userToken, modelKind));
 		}
 
 		if (modelKind === ModelKind.Ollama) {
 			const ollamaEndpoint = await this.getOllamaEndpoint();
 			const ollamaModelName = await this.getOllamaModelName();
-			return new OllamaClient(ollamaEndpoint, ollamaModelName);
+			return ok(new OllamaClient(ollamaEndpoint, ollamaModelName));
 		}
 
 		if (modelKind === ModelKind.OpenAI) {
@@ -211,14 +212,13 @@ export class AIService {
 			const openAIKey = await this.getOpenAIKey();
 
 			if (!openAIKey) {
-				toasts.error(
+				return buildFailureFromAny(
 					'When using OpenAI in a bring your own key configuration, you must provide a valid token'
 				);
-				return;
 			}
 
 			const openAI = new OpenAI({ apiKey: openAIKey, dangerouslyAllowBrowser: true });
-			return new OpenAIClient(openAIModelName, openAI);
+			return ok(new OpenAIClient(openAIModelName, openAI));
 		}
 
 		if (modelKind === ModelKind.Anthropic) {
@@ -226,14 +226,15 @@ export class AIService {
 			const anthropicKey = await this.getAnthropicKey();
 
 			if (!anthropicKey) {
-				toasts.error(
+				return buildFailureFromAny(
 					'When using Anthropic in a bring your own key configuration, you must provide a valid token'
 				);
-				return;
 			}
 
-			return new AnthropicAIClient(anthropicKey, anthropicModelName);
+			return ok(new AnthropicAIClient(anthropicKey, anthropicModelName));
 		}
+
+		return buildFailureFromAny('Failed to build ai client');
 	}
 
 	async summarizeCommit({
@@ -242,9 +243,10 @@ export class AIService {
 		useBriefStyle = false,
 		commitTemplate,
 		userToken
-	}: SummarizeCommitOpts) {
-		const aiClient = await this.buildClient(userToken);
-		if (!aiClient) return;
+	}: SummarizeCommitOpts): Promise<Result<string, Error>> {
+		const aiClientResult = await this.buildClient(userToken);
+		if (isFailure(aiClientResult)) return aiClientResult;
+		const aiClient = aiClientResult.value;
 
 		const diffLengthLimit = await this.getDiffLengthLimitConsideringAPI();
 		const defaultedCommitTemplate = commitTemplate || aiClient.defaultCommitTemplate;
@@ -272,19 +274,26 @@ export class AIService {
 			};
 		});
 
-		let message = await aiClient.evaluate(prompt);
+		const messageResult = await aiClient.evaluate(prompt);
+		if (isFailure(messageResult)) return messageResult;
+		let message = messageResult.value;
 
 		if (useBriefStyle) {
 			message = message.split('\n')[0];
 		}
 
 		const { title, description } = splitMessage(message);
-		return description ? `${title}\n\n${description}` : title;
+		return ok(description ? `${title}\n\n${description}` : title);
 	}
 
-	async summarizeBranch({ hunks, branchTemplate, userToken = undefined }: SummarizeBranchOpts) {
-		const aiClient = await this.buildClient(userToken);
-		if (!aiClient) return;
+	async summarizeBranch({
+		hunks,
+		branchTemplate,
+		userToken = undefined
+	}: SummarizeBranchOpts): Promise<Result<string, Error>> {
+		const aiClientResult = await this.buildClient(userToken);
+		if (isFailure(aiClientResult)) return aiClientResult;
+		const aiClient = aiClientResult.value;
 
 		const diffLengthLimit = await this.getDiffLengthLimitConsideringAPI();
 		const defaultedBranchTemplate = branchTemplate || aiClient.defaultBranchTemplate;
@@ -299,7 +308,10 @@ export class AIService {
 			};
 		});
 
-		const message = await aiClient.evaluate(prompt);
-		return message.replaceAll(' ', '-').replaceAll('\n', '-');
+		const messageResult = await aiClient.evaluate(prompt);
+		if (isFailure(messageResult)) return messageResult;
+		const message = messageResult.value;
+
+		return ok(message.replaceAll(' ', '-').replaceAll('\n', '-'));
 	}
 }

app/src/lib/ai/types.ts

@@ -1,4 +1,5 @@
 import type { Persisted } from '$lib/persisted/persisted';
+import type { Result } from '$lib/result';
 
 export enum ModelKind {
 	OpenAI = 'openai',
@@ -33,7 +34,7 @@ export interface PromptMessage {
 export type Prompt = PromptMessage[];
 
 export interface AIClient {
-	evaluate(prompt: Prompt): Promise<string>;
+	evaluate(prompt: Prompt): Promise<Result<string, Error>>;
 
 	defaultBranchTemplate: Prompt;
 	defaultCommitTemplate: Prompt;

app/src/lib/backend/httpClient.ts

@@ -1,3 +1,4 @@
+import { wrapAsync } from '$lib/result';
 import { PUBLIC_API_BASE_URL } from '$env/static/public';
 
 export const API_URL = new URL('/api/', PUBLIC_API_BASE_URL);
@@ -47,21 +48,41 @@ export class HttpClient {
 		return await this.request<T>(path, { ...opts, method: 'GET' });
 	}
 
+	async getSafe<T>(path: string, opts?: Omit<RequestOptions, 'body'>) {
+		return await wrapAsync<T, Error>(async () => await this.get<T>(path, opts));
+	}
+
 	async post<T>(path: string, opts?: RequestOptions) {
 		return await this.request<T>(path, { ...opts, method: 'POST' });
 	}
 
+	async postSafe<T>(path: string, opts?: RequestOptions) {
+		return await wrapAsync<T, Error>(async () => await this.post<T>(path, opts));
+	}
+
 	async put<T>(path: string, opts?: RequestOptions) {
 		return await this.request<T>(path, { ...opts, method: 'PUT' });
 	}
 
+	async putSafe<T>(path: string, opts?: RequestOptions) {
+		return await wrapAsync<T, Error>(async () => await this.put<T>(path, opts));
+	}
+
 	async patch<T>(path: string, opts?: RequestOptions) {
 		return await this.request<T>(path, { ...opts, method: 'PATCH' });
 	}
 
+	async patchSafe<T>(path: string, opts?: RequestOptions) {
+		return await wrapAsync<T, Error>(async () => await this.patch<T>(path, opts));
+	}
+
 	async delete<T>(path: string, opts?: RequestOptions) {
 		return await this.request<T>(path, { ...opts, method: 'DELETE' });
 	}
+
+	async deleteSafe<T>(path: string, opts?: RequestOptions) {
+		return await wrapAsync<T, Error>(async () => await this.delete<T>(path, opts));
+	}
 }
 
 function getApiUrl(path: string) {

app/src/lib/branch/BranchCard.svelte

@@ -17,6 +17,7 @@
 	import BranchFiles from '$lib/file/BranchFiles.svelte';
 	import { showError } from '$lib/notifications/toasts';
 	import { persisted } from '$lib/persisted/persisted';
+	import { isFailure } from '$lib/result';
 	import { SETTINGS, type Settings } from '$lib/settings/userSettings';
 	import Resizer from '$lib/shared/Resizer.svelte';
 	import { User } from '$lib/stores/user';
@@ -64,21 +65,25 @@
 
 		const hunks = branch.files.flatMap((f) => f.hunks);
 
-		try {
-			const prompt = promptService.selectedBranchPrompt(project.id);
-			const message = await aiService.summarizeBranch({
-				hunks,
-				userToken: $user?.access_token,
-				branchTemplate: prompt
-			});
+		const prompt = promptService.selectedBranchPrompt(project.id);
+		const messageResult = await aiService.summarizeBranch({
+			hunks,
+			userToken: $user?.access_token,
+			branchTemplate: prompt
+		});
 
-			if (message && message !== branch.name) {
-				branch.name = message;
-				branchController.updateBranchName(branch.id, branch.name);
-			}
-		} catch (e) {
-			console.error(e);
-			showError('Failed to generate branch name', e);
+		if (isFailure(messageResult)) {
+			console.error(messageResult.failure);
+			showError('Failed to generate branch name', messageResult.failure);
+
+			return;
+		}
+
+		const message = messageResult.value;
+
+		if (message && message !== branch.name) {
+			branch.name = message;
+			branchController.updateBranchName(branch.id, branch.name);
 		}
 	}
 

app/src/lib/commit/CommitMessageInput.svelte

@@ -11,6 +11,7 @@
 		projectCommitGenerationUseEmojis
 	} from '$lib/config/config';
 	import { showError } from '$lib/notifications/toasts';
+	import { isFailure } from '$lib/result';
 	import Checkbox from '$lib/shared/Checkbox.svelte';
 	import DropDownButton from '$lib/shared/DropDownButton.svelte';
 	import Icon from '$lib/shared/Icon.svelte';
@@ -75,27 +76,35 @@
 		}
 
 		aiLoading = true;
-		try {
-			const prompt = promptService.selectedCommitPrompt(project.id);
-			console.log(prompt);
-			const generatedMessage = await aiService.summarizeCommit({
-				hunks,
-				useEmojiStyle: $commitGenerationUseEmojis,
-				useBriefStyle: $commitGenerationExtraConcise,
-				userToken: $user?.access_token,
-				commitTemplate: prompt
-			});
 
-			if (generatedMessage) {
-				commitMessage = generatedMessage;
-			} else {
-				throw new Error('Prompt generated no response');
-			}
-		} catch (e: any) {
-			showError('Failed to generate commit message', e);
-		} finally {
+		const prompt = promptService.selectedCommitPrompt(project.id);
+
+		const generatedMessageResult = await aiService.summarizeCommit({
+			hunks,
+			useEmojiStyle: $commitGenerationUseEmojis,
+			useBriefStyle: $commitGenerationExtraConcise,
+			userToken: $user?.access_token,
+			commitTemplate: prompt
+		});
+
+		if (isFailure(generatedMessageResult)) {
+			showError('Failed to generate commit message', generatedMessageResult.failure);
 			aiLoading = false;
+			return;
 		}
+
+		const generatedMessage = generatedMessageResult.value;
+
+		if (generatedMessage) {
+			commitMessage = generatedMessage;
+		} else {
+			const errorMessage = 'Prompt generated no response';
+			showError(errorMessage, undefined);
+			aiLoading = false;
+			return;
+		}
+
+		aiLoading = false;
 	}
 
 	onMount(async () => {

app/src/lib/result.ts

@@ -0,0 +1,99 @@
+export class Panic extends Error {}
+
+export type OkVariant<Ok> = {
+	ok: true;
+	value: Ok;
+};
+
+export type FailureVariant<Err> = {
+	ok: false;
+	failure: Err;
+};
+
+export type Result<Ok, Err> = OkVariant<Ok> | FailureVariant<Err>;
+
+export function isOk<Ok, Err>(
+	subject: OkVariant<Ok> | FailureVariant<Err>
+): subject is OkVariant<Ok> {
+	return subject.ok;
+}
+
+export function isFailure<Ok, Err>(
+	subject: OkVariant<Ok> | FailureVariant<Err>
+): subject is FailureVariant<Err> {
+	return !subject.ok;
+}
+
+export function ok<Ok, Err>(value: Ok): Result<Ok, Err> {
+	return { ok: true, value };
+}
+
+export function failure<Ok, Err>(value: Err): Result<Ok, Err> {
+	return { ok: false, failure: value };
+}
+
+export function buildFailureFromAny<Ok>(value: any): Result<Ok, Error> {
+	if (value instanceof Error) {
+		return failure(value);
+	} else {
+		return failure(new Error(String(value)));
+	}
+}
+
+export function wrap<Ok, Err>(subject: () => Ok): Result<Ok, Err> {
+	try {
+		return ok(subject());
+	} catch (e) {
+		return failure(e as Err);
+	}
+}
+
+export async function wrapAsync<Ok, Err>(subject: () => Promise<Ok>): Promise<Result<Ok, Err>> {
+	try {
+		return ok(await subject());
+	} catch (e) {
+		return failure(e as Err);
+	}
+}
+
+export function unwrap<Ok, Err>(subject: Result<Ok, Err>): Ok {
+	if (isOk(subject)) {
+		return subject.value;
+	} else {
+		if (subject.failure instanceof Error) {
+			throw subject.failure;
+		} else {
+			throw new Panic(String(subject.failure));
+		}
+	}
+}
+
+export function unwrapOr<Ok, Err, Or>(subject: Result<Ok, Err>, or: Or): Ok | Or {
+	if (isOk(subject)) {
+		return subject.value;
+	} else {
+		return or;
+	}
+}
+
+export function map<Ok, Err, NewOk>(
+	subject: Result<Ok, Err>,
+	transformation: (ok: Ok) => NewOk
+): Result<NewOk, Err> {
+	if (isOk(subject)) {
+		return ok(transformation(subject.value));
+	} else {
+		return subject;
+	}
+}
+
+export function andThen<Ok, Err, NewOk>(
+	subject: Result<Ok, Err>,
+	transformation: (ok: Ok) => Result<NewOk, Err>
+): Result<NewOk, Err> {
+	if (isOk(subject)) {
+		return transformation(subject.value);
+	} else {
+		return subject;
+	}
+}