perf: lazy eval of f-strings in IRnode ctor

[charles-cooper]

25% of IR generation is in IRnode.__repr__ due to the references to self in the f-strings for panic messages. this commit switches to using assert, which accomplishes the same thing, but lazily evaluating the error messages (and the code is slightly less pretty)

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[fubuloubu]

Assert statements are removed during certain optimization modes of python

https://docs.python.org/3/reference/simple_stmts.html#the-assert-statement

[charles-cooper]

Assert statements are removed during certain optimization modes of python

https://docs.python.org/3/reference/simple_stmts.html#the-assert-statement

i'm aware of this, but i don't think people are really running vyper with asserts disabled, and we shouldn't support that behavior anyway. in addition, these are sanity checks for compiler-internal invariants, not validating user data, so we don't actually expect to trip these cases.

[charles-cooper]

the other way to do this is to actually inline all those checks, to be like

if not <cond>:
    raise CompilerPanic(...)

but i opted not to do this because the logic seemed less clear from a readability perspective.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (4dd47e3) 89.61% compared to head (0484c7b) 89.89%.
Report is 1 commits behind head on master.

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@@            Coverage Diff             @@
##           master    #3602      +/-   ##
==========================================
+ Coverage   89.61%   89.89%   +0.27%     
==========================================
  Files          80       79       -1     
  Lines       11343    11261      -82     
  Branches     2553     2545       -8     
==========================================
- Hits        10165    10123      -42     
+ Misses        791      748      -43     
- Partials      387      390       +3     

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[fubuloubu]

Assert statements are removed during certain optimization modes of python

https://docs.python.org/3/reference/simple_stmts.html#the-assert-statement

i'm aware of this, but i don't think people are really running vyper with asserts disabled, and we shouldn't support that behavior anyway. in addition, these are sanity checks for compiler-internal invariants, not validating user data, so we don't actually expect to trip these cases.

Alright, if this is the case (and it is documented), I'm on board with it since if you optimized out (which we don't really have control over how someone uses the library) it should not cause an issue, unless vyper is missing a good test case (basically we don't expect users to run into these scenarios)

[charles-cooper]

Alright, if this is the case (and it is documented), I'm on board with it since if you optimized out (which we don't really have control over how someone uses the library) it should not cause an issue, unless vyper is missing a good test case (basically we don't expect users to run into these scenarios)

we also have many other uses of assert in the codebase

[charles-cooper]

another way to do it is to allow the formatting to happen inside the helper function

def _check(cond, fstr, *args):
    if not cond:
        raise CompilerPanic(fstr.format(*args))

and then used like

  ...
  _check(cond, "xyz {}", arg1)
  ...

but i'm leaning against this because f-strings have better support in our lint setup.