Bug 40336 – Web Inspector: add programmatic API for setting breakpoints

• Status: NEW
• Component: Web Inspector

[Jesse Hallett]

From time a bug comes up that I can only reproduce in a production environment.  This leads to debugging code that is minified and that I cannot change.  In situations like this it would be really helpful to be able to programmatically set breakpoints.  For example setting a property on a function from the console to cause execution to pause when that function starts running would be great:

    > filter._onPreProcess.debug = true;

It would also be handy to be able to set the value of that property to a predicate function so that execution would only pause if the predicate returned `true`:

    > filter._onPreProcess.debug = function(/* gets arguments sent to _onPreProcess() */) { return !!arguments[1].match(/foo/); };

There are also cases where I can modify where I believe it would be useful to have other breakpoint API options.  When debugging Ruby code with the Ruby debugger I can place a call to a function called `debugger()` in my code to cause execution to pause on that line.  It would be nice to have a similar option in Webkit.

[Jesse Hallett]

I found out that you can use the `debugger;` statement for that latter case.

[Brian Burg]

This seems like a good candidate for the console command line. Firefox's GCLI (https://github.com/mozilla/gcli/) seems to have a similar interface.

There are significant challenges to making this visible to user scripts, so I think we should focus on something only made available through the inspector console.

[Radar WebKit Bug Importer]

<rdar://problem/19095011>