Hi folks, I'm struggling to modify an existing low...

# python-contributors

[Piotr Krzemiński]

Hi folks, I'm struggling to modify an existing lowering to work with Python. See this PR - 4 box tests complain about e.g.

UnboundLocalError: local variable 'properties_initialized_utf8Encoding_kt' referenced before assignment

The lowering in question is PropertyLazyInitLowering.kt. Why it happens: the lowering produces initialization functions like

def init_properties_utf8Encoding_kt():
    if not (properties_initialized_utf8Encoding_kt):
        properties_initialized_utf8Encoding_kt = True
        tmp0_byteArrayOf_0 = visitConst_other_Byte
        REPLACEMENT_BYTE_SEQUENCE = tmp0_byteArrayOf_0

and before reaching if not (properties_initialized_utf8Encoding_kt):, Python has to have properties_initialized_utf8Encoding_kt assigned to some value (here False would make sense). I wanted to add properties_initialized_utf8Encoding_kt = False just before this function definition, but I'm lost in the structure of IR elements hierarchy. I cannot spot a place where the function is added to the IR output. Even if I use some transformers that compile fine, I don't see them do their job in the output. Could you help me figure it out?

Side-questions: are there any materials where I could learn more about the internal compiler API regarding IR entities, or only browsing the code is the way to go?

[SerVB]

Some time ago @ bashor told me to look into compiler/testData/ir/irText to understand which KT text goes to which IR, but I haven't tried it yet. And for the reverse direction, IR to KT, dumpKotlinLike should help.

Regarding the first question, I have no idea, but if you want I can take a look too...

[Piotr Krzemiński]

Thanks, will check!

[Piotr Krzemiński]

A note to myself: check other lowerings, we probably need to create a lowering that inherits from DeclarationTransformer or IrElementTransformerVoid