Improve front end error handling

- handles signing error in one place

apps/desktop/src/lib/error/error.ts

@@ -0,0 +1,17 @@
+/**
+ * Error type that has both a message and a status. These errors are primarily
+ * thrown by AI services and the Octokit GitHub client.
+ */
+export interface HttpError {
+	message: string;
+	status: number;
+}
+
+/**
+ * Error type that has both a message and a code. These errors can be thrown
+ * by the back end code.
+ */
+export interface BackendError {
+	message: string;
+	code: string;
+}

apps/desktop/src/lib/error/knownErrors.ts

@@ -0,0 +1,7 @@
+export const KNOWN_ERRORS: Record<string, string> = {
+	'errors.commit.signing_failed': `
+			Commit signing failed and has now been disabled. You can configure commit signing in the project settings.
+
+			Please check our [documentation](https://docs.gitbutler.com/features/virtual-branches/verifying-commits) on setting up commit signing and verification.
+		`
+};

apps/desktop/src/lib/error/typeguards.ts

@@ -0,0 +1,23 @@
+import type { HttpError, BackendError } from './error';
+
+export function isBackendError(err: unknown): err is BackendError {
+	return (
+		typeof err === 'object' &&
+		err !== null &&
+		'message' in err &&
+		typeof err.message === 'string' &&
+		'code' in err &&
+		typeof err.code === 'string'
+	);
+}
+
+export function isHttpError(err: unknown): err is HttpError {
+	return (
+		typeof err === 'object' &&
+		err !== null &&
+		'message' in err &&
+		typeof err.message === 'string' &&
+		'code' in err &&
+		typeof err.code === 'string'
+	);
+}

apps/desktop/src/lib/notifications/toasts.ts

@@ -1,4 +1,7 @@
+import { KNOWN_ERRORS } from '$lib/error/knownErrors';
+import { isBackendError, isHttpError } from '$lib/error/typeguards';
 import { isStr } from '@gitbutler/ui/utils/string';
+import { isErrorlike } from '@gitbutler/ui/utils/typeguards';
 import posthog from 'posthog-js';
 import { writable, type Writable } from 'svelte/store';
 import type { MessageStyle } from '$lib/shared/InfoMessage.svelte';
@@ -31,22 +34,18 @@ export function showToast(toast: Toast) {
 }
 
 export function showError(title: string, error: unknown) {
-	// Silence GitHub octokit.js when disconnected
-	// TODO: Fix this elsewhere.
-	if (error instanceof Object) {
-		if (
-			'status' in error &&
-			'message' in error &&
-			error.status === 500 &&
-			error.message === 'Load failed'
-		)
-			return;
-		const message = 'message' in error ? error.message : String(error);
-		showToast({ title, error: message, style: 'error' });
-	}
-
-	if (isStr(error)) {
-		showToast({ title, error, style: 'error' });
+	if (isBackendError(error) && error.code in KNOWN_ERRORS) {
+		showToast({ title, message: KNOWN_ERRORS[error.code], error });
+	} else if (isHttpError(error)) {
+		// Silence GitHub octokit.js when disconnected. This should ideally be
+		// prevented using `navigator.onLine` to avoid making requests when
+		// working offline.
+		if (error.status === 500 && error.message === 'Load failed') return;
+		showToast({ title, error: error.message, style: 'error' });
+	} else if (isErrorlike(error)) {
+		showToast({ title, error: error.message, style: 'error' });
+	} else {
+		showToast({ title, error: String(error), style: 'error' });
 	}
 }
 

apps/desktop/src/lib/vbranches/branchController.ts

@@ -69,12 +69,7 @@ export class BranchController {
 			});
 			this.posthog.capture('Commit Successful');
 		} catch (err: any) {
-			if (err.code === 'errors.commit.signing_failed') {
-				showSignError(err);
-			} else {
-				showError('Failed to commit changes', err);
-				throw err;
-			}
+			showError('Failed to commit changes', err);
 			this.posthog.capture('Commit Failed', err);
 		}
 	}
@@ -503,12 +498,7 @@ export class BranchController {
 				targetCommitOid
 			});
 		} catch (err: any) {
-			// TODO: Probably we wanna have error code checking in a more generic way
-			if (err.code === 'errors.commit.signing_failed') {
-				showSignError(err);
-			} else {
-				showError('Failed to squash commit', err);
-			}
+			showError('Failed to squash commit', err);
 		}
 	}
 
@@ -565,12 +555,7 @@ export class BranchController {
 				message
 			});
 		} catch (err: any) {
-			// TODO: Probably we wanna have error code checking in a more generic way
-			if (err.code === 'errors.commit.signing_failed') {
-				showSignError(err);
-			} else {
-				showError('Failed to change commit message', err);
-			}
+			showError('Failed to change commit message', err);
 		}
 	}
 
@@ -583,12 +568,7 @@ export class BranchController {
 				offset
 			});
 		} catch (err: any) {
-			// TODO: Probably we wanna have error code checking in a more generic way
-			if (err.code === 'errors.commit.signing_failed') {
-				showSignError(err);
-			} else {
-				showError('Failed to insert blank commit', err);
-			}
+			showError('Failed to insert blank commit', err);
 		}
 	}
 
@@ -601,25 +581,7 @@ export class BranchController {
 				sourceBranchId
 			});
 		} catch (err: any) {
-			// TODO: Probably we wanna have error code checking in a more generic way
-			if (err.code === 'errors.commit.signing_failed') {
-				showSignError(err);
-			} else {
-				showError('Failed to move commit', err);
-			}
+			showError('Failed to move commit', err);
 		}
 	}
 }
-
-function showSignError(err: any) {
-	showToast({
-		title: 'Failed to commit due to signing error',
-		message: `
-Signing is now disabled, so subsequent commits will not fail. You can configure commit signing in the project settings.
-
-Please check our [documentation](https://docs.gitbutler.com/features/virtual-branches/verifying-commits) on setting up commit signing and verification.
-					`,
-		error: err.message,
-		style: 'error'
-	});
-}