Data transformations (meta bug)

[gregtatum]

In order to properly fix charging to callers and other Quantum Flow related filtering requests we need to re-architect how we filter and transform the data. I realized I didn't have an issue opened to track it, and it's blocking important features. Here is what needs to happen.

Work blocking filtering features

• Testing and/or flow typing existing code to ensure refactors do not break things. Add flow to process-profile.js and symbolication.js #434
• Remove the FuncStackTable in favor of a selector over the profile that effectively does the same thing, but uses the StackTable data structure. (abandoned)
• Change our profile data structure to provide a mapping from original IDs to transformed IDs (abandoned)
• Implement data transformation stack that you can push transformations onto. It cannot be arbitrarily re-ordered, but transforms can be popped off from the stack.
• Charge to call node to caller. Merge to caller #521
• Issue Charge to callers #242 Charge function to caller

Continue working on other data transformations

• Data transform: Focus on a function (not on a call node) #409 Focus on a function (not a call node)
• Data transform: Collapse recursion #243 Collapse recursion
• Data transform: Collapse all functions in a given namespace #244 Collapse all functions in a given namespace
• Data transform: Collapse all functions in a given file path #544 Collapse all functions in a given path
• Data transform: Collapse a subtree #545 Collapse subtree

@bzbarsky, @bholley I created this meta bug, since there is some work spread across multiple issues, and I'd like to keep you both up to speed on what I'm working on, since some of it is non-obvious that it's blocking some of the filtering features.

[bholley]

This is awesome - thanks Greg! Feel free to ping me if the usefulness or priority of anything is unclear.

[gregtatum]

I'm making some progress on the second bullet point:

Remove the FuncStackTable in favor of a selector over the profile that effectively does the same thing, but uses the StackTable data structure. This will allow for stable indices into tables as the data transforms.

#458

It's a bit slow going. My next step will be to attempt to rip out the existing implementation with funcStacks.

[gregtatum]

We've been (slowly) working through a solution for making this work through conversations on Slack. Here's the current gameplan, I'll update the bullet points above as needed.

• Complete the removal of FuncStacks in favor of a deDuplicateFunctionFrames selector
• Change call tree filters to use frame paths with transformed (deduplicated) frame indexes instead of function paths.
• Provide proper URL versioning, and a way to upgrade profile URLs to take this change into account

Send in PR

• Implement a transform stack that you can push onto.
• It doesn't allow for arbitrary re-ordering of transforms, only popping off of transforms.

Send in PR

• Complete charging to caller work, by adding it as a transform that works on the transform stack.

[gregtatum]

My removal of funcStacks is failing in ways that our current tests are not helpful. I created PR #476 for adding more granular tests to help move this work along, which is much more explicit in how it asserts the shape of the generated call tree. It will good for the additional data transformation work as well.