DevTools/Features/Debugger
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| Feature | Status | ETA | Owner |
| DevTools/Features/Debugger | planning (some prototype/initial impl work done) | 2011-05-13 | Kevin Dangoor |
Summary
Initial take on an integrated JavaScript debugger for Firefox.
Team
Have some thoughts on what you want out of a debugger? Inspiration on how to do it? Join us on #devtools on irc.mozilla.org
- Jim Blandy (irc: jimb): Remote debugging protocol, jsd2.
- Dave Camp (irc: dcamp): Firefox integration/UI, Remote debugging protocol.
- Jason Orendorff (irc: jorendorff): jsd2.
Repositories
- http://hg.mozilla.org/users/jblandy_mozilla.com/jsdbg2/ (JSD2)
- http://hg.mozilla.org/users/dcamp_campd.org/remote-debug/ (Remote Debugging Protocol/Firefox UI)
Release Requirements
TBD
Next Steps
- scope out the project
Related Bugs & Dependencies
See the status page for the bug list and current status.
Designs
[DevTools/Features/Debugger/Notes] has further implementation notes.
TBD
Planning
What follows is some plan-related sketching, please update appropriately. List of milestones/sprints is roughly in order.
Bootstrapping/Stack Traces
- Working remote protocol, exposing stack frames with JSD2.
- Relying on debugger statement, no breakpoints.
- Only "continue" after stopping in debugger.
- UI shell in firefox
- UI for stack traces (without arguments)
| Description | Area | Bug | Owner | Best | Likely | Worst | Status |
| Debugging global/Root actor registration/Socket Listener | Remote Proto | dcamp | 2d | 3d | 5d | ||
| Browser root actor/tab actors (not as thread-like actors) | Browser Proto | dcamp | 2d | 2d | 4d | ||
| Protocol handler thread (socket transport) | Remote Proto | dcamp | 1d | 1d | 3d | ||
| Debug Object creation and debuggerHook | JSD2 | jorendorff | In jsdbg2 branch. | ||||
| Debug Object loader | JSD2ish | jorendorff | Similar to ctypes loader? | ||||
| Debug Object support for frame inspection | JSD2 | jorendorff | type, this, older, live, callee, generator, arguments complete. | ||||
| Debug Object support for the toplevel globals in tab actor - debuggerHook spawning a nested event loop. | Browser Proto | dcamp | 2d | 2d | 4d | ||
| New execution model specification in the remote protocol | Remote Proto | jimb | |||||
| debuggerHook and "continue" exposed over remote protocol as specified. | Remote Proto | dcamp | 3d | 3d | 5d | Need to see what new spec looks like... | |
| Client JS API (socket transport) | UI Shell | dcamp | 1d | 2d | 3d | ||
| HTML UI shell per tab, in its own window | UI Shell | dcamp | 2d | 2d | 5d | ||
| UI responding to pauses (from debugger keyword) | Execution Handling | dcamp | 2d | 2d | 4d | ||
| HTML Stack frame viewer (no locals/environment yet, just | Execution Handling | dcamp | 2d | 3d | 5d |
Source Viewer
- Enough to visualize current line/stack frames/etc.
- Debug.Script.prototype.{url,startLine,length,getAllOffsets,getLineOffsets,getOffsetLine} - jorendorff
- Debug.Frame.prototype.{callee,script,offset} - jorendorff
- No source list yet, will only reflect sources handed to it in pause states.
- Can use normal view source/firebug method (loading from necko preferring the cache) for getting static script sources (in-document <script> etc).
- Needs the engine to provide sources for exotic script sources (eval/appendNode/etc.)
- Very simple source viewer, improving the source viewer can happen outside the critical path.
Execution
- throw hook
- error hook
- resume
- step into/step out/finish
Frame Tree Support
- Debug.addDebuggee() - will need for frame tree support.
- Frame tree support in the tab actors.
Environment/Property Viewer
- JSD2 support:
- Debug.Object
- Debug.Environment
- Protocol Support (actors for environments and objects)
- Pause-lifetime grips.
- Thread-lifetime grip promotion? Maybe can wait?
- UI panel - simple tree view for objects?
By the time this milestone is complete, we'll have a somewhat competent debugger if you're willing to use debugger; statements instead of breakpoints.
Source Selector
- JSD2 support
- newScript hook
- enumerate scripts? Maybe not - since we need currently need to reload anyway to recompile scripts for debugging, might be ok to always just watch the newScript hook.
- Protocol support
- new script notification.
- UI support: dropdown of available scripts, triggering loads in the source viewer.
Breakpoints
- JSD2 support.
- Protocol-side breakpoints will set physical breakpoints at each script (including newly-added scripts)
- Need to work out breakpoint persistence across reloads (needs to be done early enough to catch scripts run during the load).
- Set breakpoints in the source gutter
- Set breakpoints from a command line (?)
- Disable/Enable/Delete breakpoints
More Milestones
In no particular order...
- Web Worker debugging (might not be needed for an initial release, but would be really nice)
- Chrome debugging (probably not be needed for an initial release)
Floating Tasks
Here are a few tasks that I haven't slotted into any specific milestone, and could be tackled separately alongside the other milestones. At least some of these would block a final release of a capable debugger.
| Description | Area | Bug | Owner | Best | Likely | Worst | Status |
| E10S content process support | Remote Proto | dcamp? | 1w | 3w | 2w | ||
| Improved script origin information | JSD2 | bug 637572 | jimb | ||||
| Waive slow script dialog (jorendorff was seeing them after resuming) | JSD2 | ||||||
| Improve source viewer (after basic source viewer is added) | Firefox UI | No Owner |