Release notes v0.52.0

release notes/v0.52.0.md

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+k6 `v0.52.0` is here 🎉! Some special mentions included in this release:
+
+- [We've switched to our own fork of `goja` named `sobek`](#switch-goja-to-our-own-fork-named-sobek-3775).
+- [Panics are no longer captured](#panics-are-no-longer-being-captured-3777).
+- [We've added experimental support for TypeScript and ES6+](#experimental-support-for-typescript-and-es6-using-esbuild-3738).
+- `k6/browser` has [graduated from an experimental module](#k6browser-has-graduated-from-an-experimental-module-3793), and now has a [fully Async API](#k6browser-has-now-a-fully-async-api-browser428).
+
+## Breaking changes
+
+### Switch `goja` to our own fork named `sobek` [#3775](https://github.com/grafana/k6/pull/3775)
+
+To accelerate the development speed and bring ECMAScript Modules (ESM) support to k6 earlier (https://github.com/grafana/k6/issues/3265),
+we have decided to create a fork of the [`goja`](https://github.com/dop251/goja/) project under the Grafana GitHub organization,
+named [`sobek`](https://github.com/grafana/sobek).
+
+Starting on this release, k6 (and its extensions) now use `sobek` instead of the original `goja`, for all (of the
+publicly exposed parts of the API) except for a couple of packages that are only used internally by k6.
+
+All k6 extensions linked in the docs have had a PR for this transition opened, as explained in this [comment](https://github.com/grafana/k6/issues/3773#issuecomment-2182113677). Any extension author who hasn't gotten a PR can follow the same steps.
+
+Find further details in [#3772](https://github.com/grafana/k6/issues/3772) and [#3773](https://github.com/grafana/k6/issues/3773).
+
+### Panics are no longer being captured [#3777](https://github.com/grafana/k6/pull/3777)
+
+Since this release, Go panics are no longer being captured by k6. This means that if a panic occurs while running a test,
+the k6 process will crash, and the panic stack trace will be printed to the console.
+
+We decided to change this behavior because it's something that was left from the past as a safeguard, but it's not as
+good as it might seem. For most cases with multiple goroutines/async, it's not enough and also makes a bunch of potential
+bugs seem like less of an issue.
+
+Thus, this will help us to identify and fix bugs earlier, improve the overall stability of k6, and
+most likely make the experience of developing k6 extensions friendlier.
+
+### `lib.State` no longer has `Group` [#3750](https://github.com/grafana/k6/pull/3750)
+
+As the result of refactoring the implementation of `group` and `check` methods, in order to decouple them, and thus 
+enable other future improvements, the `lib.State` object no longer has a `Group` field.
+
+This change should not affect most users, except for a couple of extensions, for which the use of `Group` was
+already questionable:
+- `xk6-fasthttp`
+- `xk6-g0`
+
+### Other breaking changes
+
+- [#3797](https://github.com/grafana/k6/pull/3797) starts using `-` as a special value for `--archive-out` to output the archive to stdout.
+- [browser#1318](https://github.com/grafana/xk6-browser/pull/1318) makes the `Mouse.up` and `Mouse.down` methods no longer take x and y coordinates. Instead, they dispatch events on the current mouse position.
+
+## New features
+
+### Experimental support for TypeScript and ES6+ using esbuild [#3738](https://github.com/grafana/k6/pull/3738)
+
+This release of k6 introduces experimental support for TypeScript and ES6+ using esbuild, thanks to a new
+[compatibility mode](https://grafana.com/docs/k6/latest/using-k6/javascript-typescript-compatibility-mode/) named `experimental_enhanced`.
+
+```sh
+k6 run --compatibility-mode=experimental_enhanced script.js
+```
+
+With this new compatibility mode, the test source code is transformed using esbuild instead of Babel, which also means
+that source files with the extension _".ts"_ are loaded by esbuild's TypeScript loader, which results in partial 
+TypeScript support: it removes the type information but doesn't provide type safety.
+
+### `k6/browser` has graduated from an experimental module [#3793](https://github.com/grafana/k6/pull/3793)
+
+The browser module is now available as `k6/browser` instead of `k6/experimental/browser`. The previous `k6/experimental/browser` module will be removed on September 23rd, 2024. Refer to [the migration guide](https://grafana.com/docs/k6/latest/using-k6-browser/migrating-to-k6-v0-52/) for more information on how to update your scripts.
+
+### `k6/browser` has now a fully Async API [browser#428](https://github.com/grafana/xk6-browser/issues/428)
+
+This release introduces a fully Async API for the `k6/browser` module. This means that nearly all the methods in the module now return promises. This change is part of the ongoing effort to make the browser module more user-friendly and easier to use. Please see [the browser documentation](https://grafana.com/docs/k6/latest/javascript-api/k6-browser) for more information on how to use the new Async API.
+
+Related Changes:
+- [browser#1310](https://github.com/grafana/xk6-browser/pull/1310), [browser#1311](https://github.com/grafana/xk6-browser/pull/1311), [browser#1312](https://github.com/grafana/xk6-browser/pull/1312), [browser#1316](https://github.com/grafana/xk6-browser/pull/1316), [browser#1328](https://github.com/grafana/xk6-browser/pull/1328), [browser#1337](https://github.com/grafana/xk6-browser/pull/1337), [browser#1367](https://github.com/grafana/xk6-browser/pull/1367), [browser#1366](https://github.com/grafana/xk6-browser/pull/1366), [browser#1314](https://github.com/grafana/xk6-browser/pull/1314), [browser#1332](https://github.com/grafana/xk6-browser/pull/1332), [browser#1323](https://github.com/grafana/xk6-browser/pull/1323), [browser#1355](https://github.com/grafana/xk6-browser/pull/1355), [browser#1348](https://github.com/grafana/xk6-browser/pull/1348), [browser#1364](https://github.com/grafana/xk6-browser/pull/1364) Migrates `Browser`, `BrowserContext`, `ElementHandle`, `Frame`, `JSHandle`, `Keyboard`, `Locator`, `Mouse`, `Page`, `Request`, `Response` APIs to async.
+
+## UX improvements and enhancements
+
+- [#3740](https://github.com/grafana/k6/pull/3740) enables k6 extensions to initialize `ReadableStream` objects from Go code (`io.Reader`).
+- [#3798](https://github.com/grafana/k6/pull/3798) adjusts a severity level of a log message from `warn` to `debug` for cases when k6 can't detect the terminal's size.
+- [#3797](https://github.com/grafana/k6/pull/3797) makes it possible to output the archive to stdout by using `-` as the `--archive-out`. Thanks to @roobre! :bow: :tada:
+- [browser#1370](https://github.com/grafana/xk6-browser/issues/1370) makes the `GetAttribute` method now return `false` when the attribute is missing, making it easier to check for the presence of an attribute.
+- [browser#1371](https://github.com/grafana/xk6-browser/issues/1371) makes the `TextContent` method now return `false` when the element's text content cannot be grabbed (like a JS `document`), making it easier to check for the presence of text content.
+- [browser#1376](https://github.com/grafana/xk6-browser/pull/1376) makes `Request.headerValue` and `Response.headerValue` to be case-insensitive.
+- [browser#1368](https://github.com/grafana/xk6-browser/pull/1368) enhances `await` usage in Javascript examples.
+- [browser#1326](https://github.com/grafana/xk6-browser/pull/1326) adds forgotten `BrowserContext.browser` and `Page.context` mappings.
+- [browser#1360](https://github.com/grafana/xk6-browser/pull/1360), [browser#1327](https://github.com/grafana/xk6-browser/pull/1327), [browser#1335](https://github.com/grafana/xk6-browser/pull/1335), [browser#1365](https://github.com/grafana/xk6-browser/pull/1365), [browser#1313](https://github.com/grafana/xk6-browser/pull/1313), [browser#1322](https://github.com/grafana/xk6-browser/pull/1322), [browser#1330](https://github.com/grafana/xk6-browser/pull/1330), [browser#1343](https://github.com/grafana/xk6-browser/pull/1343), [browser#1345](https://github.com/grafana/xk6-browser/pull/1345), [browser#1352](https://github.com/grafana/xk6-browser/pull/1352) turns the `Browser`, `BrowserContext`, `ElementHandle`, `JSHandle`, `Keyboard`, `Mouse`, `Locator`, and `Page` types' panics into errors for stability and better error handling.
+
+## Bug fixes
+
+- [#3774](https://github.com/grafana/k6/pull/3774) fixes a `require` warning for those tests using the stdin.
+- [#3776](https://github.com/grafana/k6/pull/3776) fixes a panic caused by passing an undefined handler to timers.
+- [#3779](https://github.com/grafana/k6/pull/3779) fixes a panic caused by registering an undefined handler in gRPC streams.
+- [xk6-websockets#73](https://github.com/grafana/xk6-websockets/pull/73) fixes a panic caused by registering an undefined handler in WebSockets.
+- [browser#1369](https://github.com/grafana/xk6-browser/pull/1369) improves `valueFromRemoteObject` `null` detection by returning a Go `nil` instead of `"null"` as a `string`.
+- [browser#1386](https://github.com/grafana/xk6-browser/pull/1386) correctly handles empty string flags that don't have a value.
+- [browser#1380](https://github.com/grafana/xk6-browser/pull/1380) ensures that `JSHandle.evaluate` and `JSHandle.evaluateHandle` both set themselves as the first argument.
+- [browser#1346](https://github.com/grafana/xk6-browser/pull/1346) fixes an IFrame panic ("we either navigate top level or have old version of the navigated frame") that happens during navigation.
+- [browser#1349](https://github.com/grafana/xk6-browser/pull/1349), [browser#1354](https://github.com/grafana/xk6-browser/pull/1354) fixes `Request` mappings.
+- [browser#1334](https://github.com/grafana/xk6-browser/pull/1334) fixes an issue where clicking on a link that opens a new tab never navigates to the href link.
+- [browser#1318](https://github.com/grafana/xk6-browser/pull/1318) fixes the `Mouse.move` to correctly dispatch a `down` event.
+- [browser#1301](https://github.com/grafana/xk6-browser/pull/1301) fixes an error that occurs when working with a second tab and navigating to a URL.
+- [browser#1387](https://github.com/grafana/xk6-browser/pull/1387) fixes a panic when the new document or request is missing.
+
+## Maintenance and internal improvements
+
+- [#3752](https://github.com/grafana/k6/pull/3752), [#3767](https://github.com/grafana/k6/pull/3767), [#3770](https://github.com/grafana/k6/pull/3770), [#3780](https://github.com/grafana/k6/pull/3780), [#3782](https://github.com/grafana/k6/pull/3782), [#3795](https://github.com/grafana/k6/pull/3795) updates several dependencies.
+- [#3786](https://github.com/grafana/k6/pull/3786), [#3787](https://github.com/grafana/k6/pull/3787), [#3788](https://github.com/grafana/k6/pull/3788), [#3789](https://github.com/grafana/k6/pull/3789), [#3803](https://github.com/grafana/k6/pull/3803) updates experimental modules.
+- [#3749](https://github.com/grafana/k6/pull/3749) stops printing `goja` stack traces on panics, which has been empty since a while.
+- [#3760](https://github.com/grafana/k6/pull/3760) fixes race conditions in ramping-vus tests.
+- [#3769](https://github.com/grafana/k6/pull/3769) removes a linter setting no longer used.
+- [#3800](https://github.com/grafana/k6/pull/3800) adds test coverage for outputting the archive to stdout.
+- [browser#1298](https://github.com/grafana/xk6-browser/pull/1298) splits browser mappings into separate files for better organization and maintainability.
+- [browser#1321](https://github.com/grafana/xk6-browser/pull/1321) adds test helpers for async VU execution to reduce the boilerplate in the tests.
+- [browser#1357](https://github.com/grafana/xk6-browser/pull/1357) updates `Group` and `Tag` usage for the latest k6.
+- [browser#1361](https://github.com/grafana/xk6-browser/pull/1361) precalculates the browser version information to prevent I/O calls when the `version` and `userAgent` methods are called. This change allows the browser module to expose these methods as a sync API to be consistent with the Playwright's API.
+- [browser#1377](https://github.com/grafana/xk6-browser/pull/1377) uses the `goja` fork called `sobek` in the browser module.
+- [browser#1373](https://github.com/grafana/xk6-browser/pull/1373) provides sync and async APIs within the browser module for making the migration to the async API easier.
+
+## Roadmap
+
+### Native ECMAScript modules
+
+As mentioned above, the k6 team has forked [`goja`](https://github.com/dop251/goja/) into [`sobek`](https://github.com/grafana/sobek) and is currently working on [native ECMAScript modules support](https://github.com/grafana/k6/issues/3265). The current work in progress can be found in this [PR](https://github.com/grafana/k6/pull/3456) and any feedback is welcome.
+
+As part of that there likely will be some breaking changes due to the current not native support allowing stuff that shouldn't work. Like for example mixing [CommonJS](https://en.wikipedia.org/wiki/CommonJS) and ESM in the same file. Which is for example why we have added a [warning](https://github.com/grafana/k6/pull/3807) that it won't work. 
+
+Support across multiple files is *also* not standard but due to amount of users that seems to be mixing them *across* files a lot of work has been done to support it. It is still likely that in the future warnings and potentially at some point future breaking changes will be enacted.
+
+### OpenTelemetry metrics output
+
+We're also happy to share that this release cycle, we've been working on [xk6-output-opentelemetry](https://grafana.com/docs/k6/latest/results-output/real-time/opentelemetry/), a k6 output extension that allows you to send k6 metrics to OpenTelemetry-compatible backends. We're looking for feedback from the community. If you're interested, please try it and let us know [via the extension repository](https://github.com/grafana/xk6-output-opentelemetry/issues)!
+
+Depending on the feedback, we plan to include this extension as an experimental output in the next k6 release.