142914 2015-03-20 11:50:02 -0700 Web Inspector: Add Function Breakpoints/Tracepoints (like Symbolic Breakpoints) 2022-09-02 10:38:37 -0700 1 1 1 Unclassified WebKit Web Inspector 528+ (Nightly build) All All RESOLVED FIXED InRadar P2 Normal --- 243717 244642 243716 244717 1 joepeck hi graouts inspector-bugzilla-changes joepeck jonowells mark.lam saam webkit-bug-importer oldest_to_newest 1078909 0 joepeck 2015-03-20 11:50:02 -0700 * SUMMARY Add Function Breakpoints/Tracepoints (like Symbolic Breakpoints). Often something you want to do is "pause when window.focus is called", or "do a console.trace every time Element.prototype.querySelector is called". It is possible to swizzle these functions out and get the functionality but that is cumbersome and doesn't play well with the inspector. It would be awesome if you could create a function breakpoint in Web Inspector's UI. Or via the console like `debug(window.focus)` or `trace(Element.prototype, "querySelector")` which would show up as a Breakpoint in Web Inspector and managed by Web Inspector. We may be able to avoid swizzling if the feature is in the engine. By having Web Inspector know about and manage these function breakpoints it has the opportunity to persist the breakpoints, carry them forward through navigations so you don't need to re-set them, and apply them to sub-frames automatically. - If the function breakpoints is set on a Native Function that is not a JSBoundFunction, then e should be able to restore the breakpoint immediately after navigation (when the global object is cleared). - Tricky with native getters/setters (Object.getOwnPropertyDescriptor(MouseEvent.prototype, "altKey").get) but that could be made to work. * NOTES Existing snippets that do things like this: - https://github.com/NV/captureCalls.js - https://gist.github.com/NV/5376464 - https://github.com/paulirish/break-on-access 1078910 1 webkit-bug-importer 2015-03-20 11:50:24 -0700 <rdar://problem/20242025> 1078911 2 joepeck 2015-03-20 11:56:13 -0700 > - https://github.com/paulirish/break-on-access I believe this will even swizzle out a value descriptor with a getter/setter so that you can break on any access to the original property. That also sounds useful. Also, integration with the text editor to quickly set these breakpoints on member variables sounds useful as well. 1279183 3 joepeck 2017-02-20 19:03:51 -0800 Mark mentioned this may be easy with Native functions by inserting a middle thunk into the JITCode entry for Native Functions. This wouldn't work for built-in / Intrinsic functions though. 1889931 4 hi 2022-08-08 22:14:53 -0700 Pull request: https://github.com/WebKit/WebKit/pull/3140 1890842 5 ews-feeder 2022-08-12 02:17:29 -0700 Committed 253374@main (631ebd578bab): <https://commits.webkit.org/253374@main> Reviewed commits have been landed. Closing PR #3140 and removing active labels.