Source Mapper Improvements: Small Fixes

[tzaffi]

Problem

There were a few issues that were not resolved at the time of merging #650 .

Solution - Implement the following small improvements

• (Teal to PyTeal Source Mapper #650 already addressed) Clarify the legend for _PyTealMapper.annotate() (cf: https://github.com/tzaffi/pyteal/blob/f2a945a8eeb396e9c544b62cd3d1a6383bfc9bff/pyteal/compiler/sourcemap.py#L844)
• Rename confusing StackFrame._frame_info_is_right_before_core() (renamed in Teal to PyTeal Source Mapper #650)
• Prune unused methods in the StackFrame - PyTealFrame - TealMapItem hierarchy (Better Router Mapping #689)
• Final status checks (ensure all changes are actually necessary) (Better Router Mapping #689)
  • which of the usages of ._sframes_container are actually necessary. To see all usages: f96ef86
• audit the following test files and either remove, unskip, or provide clear commentary as to why the skipped test needs to stay in (Better Router Mapping #689 unified using STABLE_SLOT_GENERATION: bool constants currently `False):
  • tests/integration/sourcemap_monkey_integ_test.py
  • tests/unit/sourcemap_constructs311_test.py
  • tests/unit/sourcemap_constructs_allpy_test.py
  • tests/unit/sourcemap_monkey_unit_test.py
  • tests/unit/sourcemap_test.py
• At the end of Better router mapping #676 pay close attention to _PyTealSourceMap._infer() and see which lines are still being hit. Probably, there will be some situations that are no longer needed. (Better Router Mapping #689 tightened this up)
• Refactor NatalStackFrame to provide a single frame instead of a list
• Coverage triage
  • first item to notice: we could do better on subroutines such as the recursive fibonacci example:
    • with scratch slots:

      pyteal/tests/unit/sourcemap_constructs311_test.py

      Line 1901 in 6a49be7

      ( # 41 - Recursive Subroutine (scratch slots)

    • with frame pointers:

      pyteal/tests/unit/sourcemap_constructs311_test.py

      Line 1955 in 6a49be7

      ( # 42 - Recursive Subroutine (frame pointers)

• Pull in updated version of mjpieters's SourceMap to get faster R3SourceMap (cf: https://github.com/tzaffi/pyteal/blob/f2a945a8eeb396e9c544b62cd3d1a6383bfc9bff/pyteal/compiler/sourcemap.py#L75)
• Investigate the feasibility of removing the _sframes_container property from class TealComponent and whenever this is needed, simply overwrite either self.expr.stack_frames or self._stack_frames. (partially removed from much of hierarchy in Better Router Mapping #689)
  • If feasible, implement it
  • Also consider having a new method NatalStackFrame.spawn() that keeps the original NatalStackFrame as a child.
• It's likely that _PyTealSourceMapper will never be exposed to the end-user. In that case, the logic for caching build items is overly complex. This should be simplified at the end or shortly after Better router mapping #676
• Less clunky workflow and artifact access in _PyTealSourceMapper (cf: https://github.com/tzaffi/pyteal/blob/f2a945a8eeb396e9c544b62cd3d1a6383bfc9bff/pyteal/compiler/sourcemap.py#L730)

Dependencies

None

Urgency

Medium - while the urgency of any improvement individually is Low, addressing at least a few of these issues in the short term will improve the feature's usefuleness.