Dedupe directive

.changeset/wild-pandas-sell.md

@@ -0,0 +1,7 @@
+---
+'houdini-svelte': patch
+'houdini-react': patch
+'houdini': patch
+---
+
+Add @dedupe directive

e2e/_api/graphql.mjs

@@ -122,6 +122,7 @@ export const typeDefs = /* GraphQL */ `
 			before: String
 			first: Int
 			last: Int
+			delay: Int
 			snapshot: String!
 		): UserConnection!
 		usersList(limit: Int = 4, offset: Int, snapshot: String!): [User!]!
@@ -450,7 +451,12 @@ export const resolvers = {
 			}
 			throw new GraphQLError('No authorization found', { code: 403 })
 		},
-		usersConnection(_, args) {
+		usersConnection: async (_, args) => {
+			// simulate network delay
+			if (args.delay) {
+				await sleep(args.delay)
+			}
+
 			return connectionFromArray(getUserSnapshot(args.snapshot), args)
 		},
 		user: async (_, args) => {

e2e/_api/schema.graphql

@@ -110,6 +110,7 @@ type Query {
 		before: String
 		first: Int
 		last: Int
+        delay: Int
 		snapshot: String!
 	): UserConnection!
 	usersList(limit: Int = 4, offset: Int, snapshot: String!): [User!]!

e2e/react/src/routes/pagination/query/dedupe/+page.gql

@@ -0,0 +1,15 @@
+query DedupePaginationFetch {
+	usersConnection(first: 2, delay: 1000, snapshot: "dedupe-pagination-fetch") @paginate {
+		pageInfo {
+			hasNextPage
+			hasPreviousPage
+			startCursor
+			endCursor
+		}
+		edges {
+			node {
+				name
+			}
+		}
+	}
+}

e2e/react/src/routes/pagination/query/dedupe/+page.tsx

@@ -0,0 +1,21 @@
+import { PageProps } from './$types'
+
+export default function ({ DedupePaginationFetch, DedupePaginationFetch$handle }: PageProps) {
+	return (
+		<div>
+			<div id="result">
+				{DedupePaginationFetch.usersConnection.edges
+					.map(({ node }) => node?.name)
+					.join(', ')}
+			</div>
+
+			<div id="pageInfo">
+				{JSON.stringify(DedupePaginationFetch.usersConnection.pageInfo)}
+			</div>
+
+			<button id="next" onClick={() => DedupePaginationFetch$handle.loadNext()}>
+				next
+			</button>
+		</div>
+	)
+}

e2e/react/src/routes/pagination/query/dedupe/spec.ts

@@ -0,0 +1,40 @@
+import test, { expect, type Response } from '@playwright/test'
+import { routes } from '~/utils/routes'
+import { expect_1_gql, expect_to_be, goto } from '~/utils/testsHelper'
+
+test('pagination before previous request was finished', async ({ page }) => {
+	await goto(page, routes.pagination_dedupe)
+
+	await expect_to_be(page, 'Bruce Willis, Samuel Jackson')
+
+	// Adapted from `expect_n_gql` in lib/utils/testsHelper.ts
+	let nbResponses = 0
+	async function fnRes(response: Response) {
+		if (response.url().endsWith(routes.api)) {
+			nbResponses++
+		}
+	}
+
+	page.on('response', fnRes)
+
+	// Click the "next page" button twice
+	await page.click('button[id=next]')
+	await page.click('button[id=next]')
+
+	// Give the query some time to execute
+	await page.waitForTimeout(1000)
+
+	// Check that only one gql request happened.
+	expect(nbResponses).toBe(1)
+
+	page.removeListener('response', fnRes)
+
+	await expect_to_be(page, 'Bruce Willis, Samuel Jackson, Morgan Freeman, Tom Hanks')
+
+	// Fetching the 3rd page still works ok.
+	await expect_1_gql(page, 'button[id=next]')
+	await expect_to_be(
+		page,
+		'Bruce Willis, Samuel Jackson, Morgan Freeman, Tom Hanks, Will Smith, Harrison Ford'
+	)
+})

e2e/react/src/utils/routes.ts

@@ -1,4 +1,5 @@
 export const routes = {
+	api: '/_api',
 	hello: '/hello-world',
 	scalars: '/scalars',
 	componentFields_simple: '/component_fields/simple',
@@ -10,6 +11,7 @@ export const routes = {
 	pagination_query_forwards: '/pagination/query/connection-forwards',
 	pagination_query_bidirectional: '/pagination/query/connection-bidirectional',
 	pagination_query_offset: '/pagination/query/offset',
+	pagination_dedupe: '/pagination/query/dedupe',
 	pagination_query_offset_singlepage: '/pagination/query/offset-singlepage',
 	pagination_query_offset_variable: '/pagination/query/offset-variable/2',
 	optimistic_keys: '/optimistic-keys',

packages/houdini-react/src/runtime/hooks/useDocumentHandle.ts

@@ -56,9 +56,21 @@ export function useDocumentHandle<
 		) => {
 			return async (value: any) => {
 				setLoading(true)
-				const result = await fn(value)
+				let result: _Result | null = null
+				let err: Error | null = null
+				try {
+					result = await fn(value)
+				} catch (e) {
+					err = e as Error
+				}
 				setLoading(false)
-				return result
+				// ignore abort errors when loading pages
+				if (err && err.name !== 'AbortError') {
+					throw err
+				}
+
+				// we're done
+				return result || observer.state
 			}
 		}
 

packages/houdini-svelte/src/runtime/stores/pagination/query.ts

@@ -88,12 +88,30 @@ export class QueryStoreCursor<
 		args?: Parameters<Required<CursorHandlers<_Data, _Input>>['loadPreviousPage']>[0]
 	) {
 		const handlers = await this.#handlers()
-		return await handlers.loadPreviousPage(args)
+		try {
+			return await handlers.loadPreviousPage(args)
+		} catch (e) {
+			const err = e as Error
+			// if the error is an abort error then we don't want to throw
+			if (err.name === 'AbortError') {
+			} else {
+				throw err
+			}
+		}
 	}
 
 	async loadNextPage(args?: Parameters<CursorHandlers<_Data, _Input>['loadNextPage']>[0]) {
 		const handlers = await this.#handlers()
-		return await handlers.loadNextPage(args)
+		try {
+			return await handlers.loadNextPage(args)
+		} catch (e) {
+			const err = e as Error
+			// if the error is an abort error then we don't want to throw
+			if (err.name === 'AbortError') {
+			} else {
+				throw err
+			}
+		}
 	}
 
 	subscribe(

packages/houdini/src/codegen/generators/artifacts/index.ts

@@ -187,6 +187,9 @@ export default function artifactGenerator(stats: {
 					let selectionSet: graphql.SelectionSetNode
 					let originalSelectionSet: graphql.SelectionSetNode | null = null
 
+					// extract the deduplication behavior
+					let dedupe: QueryArtifact['dedupe']
+
 					const fragmentDefinitions = doc.document.definitions
 						.filter<graphql.FragmentDefinitionNode>(
 							(definition): definition is graphql.FragmentDefinitionNode =>
@@ -222,6 +225,22 @@ export default function artifactGenerator(stats: {
 							})
 						}
 
+						const dedupeDirective = operation.directives?.find(
+							(directive) => directive.name.value === config.dedupeDirective
+						)
+						if (dedupeDirective) {
+							const cancelFirstArg = dedupeDirective.arguments?.find(
+								(arg) => arg.name.value === 'cancelFirst'
+							)
+
+							dedupe =
+								cancelFirstArg &&
+								cancelFirstArg.value.kind === 'BooleanValue' &&
+								cancelFirstArg.value
+									? 'first'
+									: 'last'
+						}
+
 						// use this selection set
 						selectionSet = operation.selectionSet
 						if (originalParsed.definitions[0].kind === 'OperationDefinition') {
@@ -320,6 +339,13 @@ export default function artifactGenerator(stats: {
 					const hash_value = hashPluginBaseRaw({ config, document: { ...doc, artifact } })
 					artifact.hash = hash_value
 
+					if (
+						artifact.kind === 'HoudiniQuery' ||
+						(artifact.kind === 'HoudiniMutation' && dedupe)
+					) {
+						artifact.dedupe = dedupe
+					}
+
 					// apply the visibility mask to the artifact so that only
 					// fields in the direct selection are visible
 					applyMask(