fix(assets): Fixes assets generation when using custom paths and configs (#10567)

* fix(assets): Fixes assets generation when using custom paths and configs

* fix: tests

* fix: make sure remote files don't end up in nested folders by accident

* test: add a whole bunch of tests

* chore: changeset

15 files changed, 272 insertions, 32 deletions

diff --git a/.changeset/few-avocados-notice.md b/.changeset/few-avocados-notice.md
new file mode 100644
index 000000000..72c8ba249
--- /dev/null
+++ b/.changeset/few-avocados-notice.md
@@ -0,0 +1,5 @@
+---
+"astro": patch
+---
+
+Fixes `astro:assets` not working when using complex config with `vite.build.rollupOptions.output.assetFileNames`
diff --git a/packages/astro/e2e/dev-toolbar-audits.test.js b/packages/astro/e2e/dev-toolbar-audits.test.js
index 5066376e4..9a628a1c0 100644
--- a/packages/astro/e2e/dev-toolbar-audits.test.js
+++ b/packages/astro/e2e/dev-toolbar-audits.test.js
@@ -44,7 +44,7 @@ test.describe('Dev Toolbar - Audits', () => {
 		await appButton.click();
 	});
 
-	test('can handle mutations zzz', async ({ page, astro }) => {
+	test('can handle mutations', async ({ page, astro }) => {
 		await page.goto(astro.resolveUrl('/audits-mutations'));
 
 		const toolbar = page.locator('astro-dev-toolbar');
diff --git a/packages/astro/src/assets/build/generate.ts b/packages/astro/src/assets/build/generate.ts
index 496dc1e6e..f20934538 100644
--- a/packages/astro/src/assets/build/generate.ts
+++ b/packages/astro/src/assets/build/generate.ts
@@ -1,5 +1,5 @@
 import fs, { readFileSync } from 'node:fs';
-import { basename, join } from 'node:path/posix';
+import { basename } from 'node:path/posix';
 import { dim, green } from 'kleur/colors';
 import type PQueue from 'p-queue';
 import type { AstroConfig } from '../../@types/astro.js';
@@ -9,7 +9,7 @@ import { getTimeStat } from '../../core/build/util.js';
 import { AstroError } from '../../core/errors/errors.js';
 import { AstroErrorData } from '../../core/errors/index.js';
 import type { Logger } from '../../core/logger/core.js';
-import { isRemotePath, prependForwardSlash } from '../../core/path.js';
+import { isRemotePath, removeLeadingForwardSlash } from '../../core/path.js';
 import { isServerLikeOutput } from '../../prerender/utils.js';
 import type { MapValue } from '../../type-utils.js';
 import { getConfiguredImageService } from '../internal.js';
@@ -89,10 +89,7 @@ export async function prepareAssetsGenerationEnv(
 }
 
 function getFullImagePath(originalFilePath: string, env: AssetEnv): URL {
-	return new URL(
-		'.' + prependForwardSlash(join(env.assetsFolder, basename(originalFilePath))),
-		env.serverRoot
-	);
+	return new URL(removeLeadingForwardSlash(originalFilePath), env.serverRoot);
 }
 
 export async function generateImagesForPath(
@@ -115,7 +112,7 @@ export async function generateImagesForPath(
 	// For instance, the same image could be referenced in both a server-rendered page and build-time-rendered page
 	if (
 		!env.isSSR &&
-		!isRemotePath(originalFilePath) &&
+		transformsAndPath.originalSrcPath &&
 		!globalThis.astroAsset.referencedImages?.has(transformsAndPath.originalSrcPath)
 	) {
 		try {
diff --git a/packages/astro/src/assets/internal.ts b/packages/astro/src/assets/internal.ts
index 5cd3cc7bf..6a3becde3 100644
--- a/packages/astro/src/assets/internal.ts
+++ b/packages/astro/src/assets/internal.ts
@@ -74,9 +74,9 @@ export async function getImage(
 		}
 	}
 
-	const originalPath = isESMImportedImage(resolvedOptions.src)
+	const originalFilePath = isESMImportedImage(resolvedOptions.src)
 		? resolvedOptions.src.fsPath
-		: resolvedOptions.src;
+		: undefined; // Only set for ESM imports, where we do have a file path
 
 	// Clone the `src` object if it's an ESM import so that we don't refer to any properties of the original object
 	// Causing our generate step to think the image is used outside of the image optimization pipeline
@@ -112,10 +112,14 @@ export async function getImage(
 		!(isRemoteImage(validatedOptions.src) && imageURL === validatedOptions.src)
 	) {
 		const propsToHash = service.propertiesToHash ?? DEFAULT_HASH_PROPS;
-		imageURL = globalThis.astroAsset.addStaticImage(validatedOptions, propsToHash, originalPath);
+		imageURL = globalThis.astroAsset.addStaticImage(
+			validatedOptions,
+			propsToHash,
+			originalFilePath
+		);
 		srcSets = srcSetTransforms.map((srcSet) => ({
 			transform: srcSet.transform,
-			url: globalThis.astroAsset.addStaticImage!(srcSet.transform, propsToHash, originalPath),
+			url: globalThis.astroAsset.addStaticImage!(srcSet.transform, propsToHash, originalFilePath),
 			descriptor: srcSet.descriptor,
 			attributes: srcSet.attributes,
 		}));
diff --git a/packages/astro/src/assets/types.ts b/packages/astro/src/assets/types.ts
index b77180e20..29cf1ef9e 100644
--- a/packages/astro/src/assets/types.ts
+++ b/packages/astro/src/assets/types.ts
@@ -11,7 +11,7 @@ export type ImageOutputFormat = (typeof VALID_OUTPUT_FORMATS)[number] | (string
 export type AssetsGlobalStaticImagesList = Map<
 	string,
 	{
-		originalSrcPath: string;
+		originalSrcPath: string | undefined;
 		transforms: Map<string, { finalPath: string; transform: ImageTransform }>;
 	}
 >;
@@ -21,7 +21,7 @@ declare global {
 	var astroAsset: {
 		imageService?: ImageService;
 		addStaticImage?:
-			| ((options: ImageTransform, hashProperties: string[], fsPath: string) => string)
+			| ((options: ImageTransform, hashProperties: string[], fsPath: string | undefined) => string)
 			| undefined;
 		staticImages?: AssetsGlobalStaticImagesList;
 		referencedImages?: Set<string>;
diff --git a/packages/astro/src/assets/utils/transformToPath.ts b/packages/astro/src/assets/utils/transformToPath.ts
index 0cac1a671..9a91098cc 100644
--- a/packages/astro/src/assets/utils/transformToPath.ts
+++ b/packages/astro/src/assets/utils/transformToPath.ts
@@ -1,19 +1,18 @@
-import { basename, extname } from 'node:path';
+import { basename, dirname, extname } from 'node:path';
 import { deterministicString } from 'deterministic-object-hash';
 import { removeQueryString } from '../../core/path.js';
 import { shorthash } from '../../runtime/server/shorthash.js';
 import type { ImageTransform } from '../types.js';
 import { isESMImportedImage } from './imageKind.js';
 
-export function propsToFilename(transform: ImageTransform, hash: string) {
-	let filename = removeQueryString(
-		isESMImportedImage(transform.src) ? transform.src.src : transform.src
-	);
+export function propsToFilename(filePath: string, transform: ImageTransform, hash: string) {
+	let filename = decodeURIComponent(removeQueryString(filePath));
 	const ext = extname(filename);
-	filename = decodeURIComponent(basename(filename, ext));
+	filename = basename(filename, ext);
+	const prefixDirname = isESMImportedImage(transform.src) ? dirname(filePath) : '';
 
 	let outputExt = transform.format ? `.${transform.format}` : ext;
-	return `/${filename}_${hash}${outputExt}`;
+	return decodeURIComponent(`${prefixDirname}/${filename}_${hash}${outputExt}`);
 }
 
 export function hashTransform(
diff --git a/packages/astro/src/assets/vite-plugin-assets.ts b/packages/astro/src/assets/vite-plugin-assets.ts
index 563874a56..fe92b2538 100644
--- a/packages/astro/src/assets/vite-plugin-assets.ts
+++ b/packages/astro/src/assets/vite-plugin-assets.ts
@@ -9,6 +9,7 @@ import {
 	appendForwardSlash,
 	joinPaths,
 	prependForwardSlash,
+	removeBase,
 	removeQueryString,
 } from '../core/path.js';
 import { isServerLikeOutput } from '../prerender/utils.js';
@@ -91,7 +92,7 @@ export default function assets({
 					return;
 				}
 
-				globalThis.astroAsset.addStaticImage = (options, hashProperties, originalPath) => {
+				globalThis.astroAsset.addStaticImage = (options, hashProperties, originalFSPath) => {
 					if (!globalThis.astroAsset.staticImages) {
 						globalThis.astroAsset.staticImages = new Map<
 							string,
@@ -102,13 +103,18 @@ export default function assets({
 						>();
 					}
 
-					// Rollup will copy the file to the output directory, this refer to this final path, not to the original path
+					// Rollup will copy the file to the output directory, as such this is the path in the output directory, including the asset prefix / base
 					const ESMImportedImageSrc = isESMImportedImage(options.src)
 						? options.src.src
 						: options.src;
 					const fileExtension = extname(ESMImportedImageSrc);
-					const pf = getAssetsPrefix(fileExtension, settings.config.build.assetsPrefix);
-					const finalOriginalImagePath = ESMImportedImageSrc.replace(pf, '');
+					const assetPrefix = getAssetsPrefix(fileExtension, settings.config.build.assetsPrefix);
+
+					// This is the path to the original image, from the dist root, without the base or the asset prefix (e.g. /_astro/image.hash.png)
+					const finalOriginalPath = removeBase(
+						removeBase(ESMImportedImageSrc, settings.config.base),
+						assetPrefix
+					);
 
 					const hash = hashTransform(
 						options,
@@ -117,21 +123,26 @@ export default function assets({
 					);
 
 					let finalFilePath: string;
-					let transformsForPath = globalThis.astroAsset.staticImages.get(finalOriginalImagePath);
+					let transformsForPath = globalThis.astroAsset.staticImages.get(finalOriginalPath);
 					let transformForHash = transformsForPath?.transforms.get(hash);
+
+					// If the same image has already been transformed with the same options, we'll reuse the final path
 					if (transformsForPath && transformForHash) {
 						finalFilePath = transformForHash.finalPath;
 					} else {
 						finalFilePath = prependForwardSlash(
-							joinPaths(settings.config.build.assets, propsToFilename(options, hash))
+							joinPaths(
+								isESMImportedImage(options.src) ? '' : settings.config.build.assets,
+								prependForwardSlash(propsToFilename(finalOriginalPath, options, hash))
+							)
 						);
 
 						if (!transformsForPath) {
-							globalThis.astroAsset.staticImages.set(finalOriginalImagePath, {
-								originalSrcPath: originalPath,
+							globalThis.astroAsset.staticImages.set(finalOriginalPath, {
+								originalSrcPath: originalFSPath,
 								transforms: new Map(),
 							});
-							transformsForPath = globalThis.astroAsset.staticImages.get(finalOriginalImagePath)!;
+							transformsForPath = globalThis.astroAsset.staticImages.get(finalOriginalPath)!;
 						}
 
 						transformsForPath.transforms.set(hash, {
@@ -143,7 +154,7 @@ export default function assets({
 					// The paths here are used for URLs, so we need to make sure they have the proper format for an URL
 					// (leading slash, prefixed with the base / assets prefix, encoded, etc)
 					if (settings.config.build.assetsPrefix) {
-						return encodeURI(joinPaths(pf, finalFilePath));
+						return encodeURI(joinPaths(assetPrefix, finalFilePath));
 					} else {
 						return encodeURI(prependForwardSlash(joinPaths(settings.config.base, finalFilePath)));
 					}
diff --git a/packages/astro/test/core-image-unconventional-settings.test.js b/packages/astro/test/core-image-unconventional-settings.test.js
new file mode 100644
index 000000000..9ecf6aab6
--- /dev/null
+++ b/packages/astro/test/core-image-unconventional-settings.test.js
@@ -0,0 +1,187 @@
+import assert from 'node:assert/strict';
+import { describe, it } from 'node:test';
+import * as cheerio from 'cheerio';
+
+import { testImageService } from './test-image-service.js';
+import { loadFixture } from './test-utils.js';
+
+/**
+ ** @typedef {import('../src/@types/astro').AstroInlineConfig & { root?: string | URL }} AstroInlineConfig
+ */
+
+/** @type {AstroInlineConfig} */
+const defaultSettings = {
+	root: './fixtures/core-image-unconventional-settings/',
+	image: {
+		service: testImageService(),
+	},
+};
+
+describe('astro:assets - Support unconventional build settings properly', () => {
+	/** @type {import('./test-utils').Fixture} */
+	let fixture;
+
+	it('supports assetsPrefix', async () => {
+		fixture = await loadFixture({
+			...defaultSettings,
+			build: {
+				assetsPrefix: 'https://cdn.example.com/',
+			},
+		});
+		await fixture.build();
+
+		const html = await fixture.readFile('/index.html');
+		const $ = cheerio.load(html);
+		const src = $('#walrus-img').attr('src');
+		assert.equal(src.startsWith('https://cdn.example.com/'), true);
+
+		const data = await fixture.readFile(src.replace('https://cdn.example.com/', ''), null);
+		assert.equal(data instanceof Buffer, true);
+	});
+
+	it('supports base', async () => {
+		fixture = await loadFixture({
+			...defaultSettings,
+			build: {
+				base: '/subdir/',
+			},
+		});
+		await fixture.build();
+
+		const html = await fixture.readFile('/index.html');
+		const $ = cheerio.load(html);
+		const src = $('#walrus-img').attr('src');
+		const data = await fixture.readFile(src.replace('/subdir/', ''), null);
+		assert.equal(data instanceof Buffer, true);
+	});
+
+	// This test is a bit of a stretch, but it's a good sanity check, `assetsPrefix` should take precedence over `base` in this context
+	it('supports assetsPrefix + base', async () => {
+		fixture = await loadFixture({
+			...defaultSettings,
+			build: {
+				assetsPrefix: 'https://cdn.example.com/',
+				base: '/subdir/',
+			},
+		});
+		await fixture.build();
+
+		const html = await fixture.readFile('/index.html');
+		const $ = cheerio.load(html);
+		const src = $('#walrus-img').attr('src');
+		assert.equal(src.startsWith('https://cdn.example.com/'), true);
+
+		const data = await fixture.readFile(src.replace('https://cdn.example.com/', ''), null);
+		assert.equal(data instanceof Buffer, true);
+	});
+
+	it('supports custom build.assets', async () => {
+		fixture = await loadFixture({
+			...defaultSettings,
+			build: {
+				assets: 'assets',
+			},
+		});
+		await fixture.build();
+
+		const html = await fixture.readFile('/index.html');
+		const $ = cheerio.load(html);
+
+		const unoptimizedSrc = $('#walrus-img-unoptimized').attr('src');
+		assert.equal(unoptimizedSrc.startsWith('/assets/'), true);
+
+		const src = $('#walrus-img').attr('src');
+		const data = await fixture.readFile(src, null);
+
+		assert.equal(data instanceof Buffer, true);
+	});
+
+	it('supports custom vite.build.rollupOptions.output.assetFileNames', async () => {
+		fixture = await loadFixture({
+			...defaultSettings,
+			vite: {
+				build: {
+					rollupOptions: {
+						output: {
+							assetFileNames: 'images/hello_[name].[ext]',
+						},
+					},
+				},
+			},
+		});
+		await fixture.build();
+
+		const html = await fixture.readFile('/index.html');
+		const $ = cheerio.load(html);
+		const unoptimizedSrc = $('#walrus-img-unoptimized').attr('src');
+		assert.equal(unoptimizedSrc, '/images/hello_light_walrus.avif');
+
+		const src = $('#walrus-img').attr('src');
+		const data = await fixture.readFile(src, null);
+
+		assert.equal(data instanceof Buffer, true);
+	});
+
+	it('supports complex vite.build.rollupOptions.output.assetFileNames', async () => {
+		fixture = await loadFixture({
+			...defaultSettings,
+			vite: {
+				build: {
+					rollupOptions: {
+						output: {
+							assetFileNames: 'assets/[hash]/[name][extname]',
+						},
+					},
+				},
+			},
+		});
+		await fixture.build();
+
+		const html = await fixture.readFile('/index.html');
+		const $ = cheerio.load(html);
+		const unoptimizedSrc = $('#walrus-img-unoptimized').attr('src');
+		const originalData = await fixture.readFile(unoptimizedSrc, null);
+		assert.equal(originalData instanceof Buffer, true);
+
+		const src = $('#walrus-img').attr('src');
+		const data = await fixture.readFile(src, null);
+
+		assert.equal(data instanceof Buffer, true);
+	});
+
+	it('supports custom vite.build.rollupOptions.output.assetFileNames with assetsPrefix', async () => {
+		fixture = await loadFixture({
+			...defaultSettings,
+			vite: {
+				build: {
+					rollupOptions: {
+						output: {
+							assetFileNames: 'images/hello_[name].[ext]',
+						},
+					},
+				},
+			},
+			build: {
+				assetsPrefix: 'https://cdn.example.com/',
+			},
+		});
+		await fixture.build();
+
+		const html = await fixture.readFile('/index.html');
+		const $ = cheerio.load(html);
+		const unoptimizedSrc = $('#walrus-img-unoptimized').attr('src');
+		assert.equal(unoptimizedSrc, 'https://cdn.example.com/images/hello_light_walrus.avif');
+
+		const unoptimizedData = await fixture.readFile(
+			unoptimizedSrc.replace('https://cdn.example.com/', ''),
+			null
+		);
+		assert.equal(unoptimizedData instanceof Buffer, true);
+
+		const src = $('#walrus-img').attr('src');
+		assert.equal(src.startsWith('https://cdn.example.com/'), true);
+
+		const data = await fixture.readFile(src.replace('https://cdn.example.com/', ''), null);
+		assert.equal(data instanceof Buffer, true);
+	});
+});
diff --git a/packages/astro/test/fixtures/core-image-unconventional-settings/package.json b/packages/astro/test/fixtures/core-image-unconventional-settings/package.json
new file mode 100644
index 000000000..c3a0834e8
--- /dev/null
+++ b/packages/astro/test/fixtures/core-image-unconventional-settings/package.json
@@ -0,0 +1,8 @@
+{
+  "name": "@test/core-image-unconventional-settings",
+  "version": "0.0.0",
+  "private": true,
+  "dependencies": {
+    "astro": "workspace:*"
+  }
+}
diff --git a/packages/astro/test/fixtures/core-image-unconventional-settings/src/assets/light_walrus.avif b/packages/astro/test/fixtures/core-image-unconventional-settings/src/assets/light_walrus.avif
new file mode 100644
index 000000000..89e1c3a14
--- /dev/null
+++ b/packages/astro/test/fixtures/core-image-unconventional-settings/src/assets/light_walrus.avif
diff --git a/packages/astro/test/fixtures/core-image-unconventional-settings/src/pages/index.astro b/packages/astro/test/fixtures/core-image-unconventional-settings/src/pages/index.astro
new file mode 100644
index 000000000..f896aad06
--- /dev/null
+++ b/packages/astro/test/fixtures/core-image-unconventional-settings/src/pages/index.astro
@@ -0,0 +1,7 @@
+---
+import { Image } from "astro:assets";
+import walrus from "../assets/light_walrus.avif";
+---
+
+<img src={walrus.src} alt="A walrus" id="walrus-img-unoptimized" />
+<Image src={walrus} alt="A walrus" id="walrus-img" />
diff --git a/packages/astro/test/fixtures/core-image-unconventional-settings/tsconfig.json b/packages/astro/test/fixtures/core-image-unconventional-settings/tsconfig.json
new file mode 100644
index 000000000..b5bf6a715
--- /dev/null
+++ b/packages/astro/test/fixtures/core-image-unconventional-settings/tsconfig.json
@@ -0,0 +1,9 @@
+{
+  "extends": "astro/tsconfigs/base",
+  "compilerOptions": {
+    "baseUrl": ".",
+    "paths": {
+      "~/assets/*": ["src/assets/*"]
+    },
+  }
+}
diff --git a/packages/astro/test/image-deletion.test.js b/packages/astro/test/image-deletion.test.js
index cb4b464bf..9af94a754 100644
--- a/packages/astro/test/image-deletion.test.js
+++ b/packages/astro/test/image-deletion.test.js
@@ -3,7 +3,7 @@ import { before, describe, it } from 'node:test';
 import { testImageService } from './test-image-service.js';
 import { loadFixture } from './test-utils.js';
 
-describe('astro:assets - delete images that are unused zzz', () => {
+describe('astro:assets - delete images that are unused', () => {
 	/** @type {import('./test-utils.js').Fixture} */
 	let fixture;
 
diff --git a/packages/internal-helpers/src/path.ts b/packages/internal-helpers/src/path.ts
index 50daf97bc..6b1c98125 100644
--- a/packages/internal-helpers/src/path.ts
+++ b/packages/internal-helpers/src/path.ts
@@ -97,3 +97,10 @@ export function fileExtension(path: string) {
 	const ext = path.split('.').pop();
 	return ext !== path ? `.${ext}` : '';
 }
+
+export function removeBase(path: string, base: string) {
+	if (path.startsWith(base)) {
+		return path.slice(removeTrailingForwardSlash(base).length);
+	}
+	return path;
+}
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index e939aac94..5e3f64bcd 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -2553,6 +2553,12 @@ importers:
         specifier: workspace:*
         version: link:../../..
 
+  packages/astro/test/fixtures/core-image-unconventional-settings:
+    dependencies:
+      astro:
+        specifier: workspace:*
+        version: link:../../..
+
   packages/astro/test/fixtures/css-assets:
     dependencies:
       '@test/astro-font-awesome-package':