Migrate typechecking to ty #242

kracekumar · 2025-12-17T23:43:04Z

Description

The goal of the PR is to introduce ty as default type checker while deprecating mypy.
So far all the changes in the PR is meant to satisfy the ty checker. It is stricter and highly opinionated. So far the changes seems to be straight forward but required a re-factoring, adding ignore statements, changing types to appropriate types.
You can run ty by

$uv run ty check
All checks passed!

Performance of mypy vs ty

kracekumar@Mac ~/c/litecli (krace/ty)> time uv run ty check -v
INFO Defaulting to python-platform `darwin`
INFO Python version: Python 3.9, platform: darwin
INFO Indexed 25 file(s) in 0.003s
All checks passed!

________________________________________________________
Executed in  116.63 millis    fish           external
   usr time  224.67 millis    0.11 millis  224.56 millis
   sys time   69.86 millis    1.10 millis   68.76 millis

kracekumar@Mac ~/c/litecli (krace/ty)> time uv run mypy .
litecli/__init__.py: error: Source file found twice under different module names: "litecli" and "litecli.__init__"
litecli/__init__.py: note: See https://mypy.readthedocs.io/en/stable/running_mypy.html#mapping-file-paths-to-modules for more info
litecli/__init__.py: note: Common resolutions include: a) adding `__init__.py` somewhere, b) using `--explicit-package-bases` or adjusting MYPYPATH
Found 1 error in 1 file (errors prevented further checking)

________________________________________________________
Executed in  859.16 millis    fish           external
   usr time  185.33 millis    0.17 millis  185.16 millis
   sys time  101.28 millis    2.51 millis   98.77 millis

kracekumar@Mac ~/c/litecli (krace/ty) [2]>

The pyproject.yamlcontains minimal configuration for ty.
Here is the amp thread to replace, ty: ignore to type: ignore.

Checklist

I've added this contribution to the CHANGELOG.md file.

kracekumar · 2025-12-19T23:32:21Z

litecli/clistyle.py


 # map Pygments tokens (ptk 1.0) to class names (ptk 2.0).
-TOKEN_TO_PROMPT_STYLE: dict[Token, str] = {
+TOKEN_TO_PROMPT_STYLE: dict[_TokenType, str] = {


Mapping to accurate type so ty doesn't complain.

kracekumar · 2025-12-19T23:33:07Z

litecli/config.py

    from litecli import __file__ as package_root

-    package_root = os.path.dirname(package_root)
+    package_root = os.path.dirname(str(package_root))


ty doesn't like package_root as it comes from import reference, hence converting to string.

kracekumar · 2025-12-19T23:33:52Z

litecli/main.py


 try:
-    from sqlean import OperationalError, sqlite_version
+    from sqlean import OperationalError, sqlite_version  # ty: ignore[unresolved-import]


sqlean has no type definitions, hence need to ignore all places. At runtime, the methods are available.

Maybe create types for sqlean.

kracekumar · 2025-12-19T23:35:19Z

litecli/packages/parseutils.py

    "all_punctuations": re.compile(r"([^\s]+)$"),
 }

+LAST_WORD_INCLUDE_TYPE = Literal["alphanum_underscore", "many_punctuations", "most_punctuations", "all_punctuations"]


Ty later complains the value passed is str and so declare and import later.

kracekumar · 2025-12-19T23:36:00Z

litecli/packages/special/__init__.py

+    write_once,
+    write_pipe_once,
+    close_tee,
+)


ty doesn't like when these methods are accessed like special.xyz()when it is missing in the init.py

There may be scope to improve over all import systems.

kracekumar · 2025-12-19T23:36:48Z

litecli/packages/special/favoritequeries.py

        self.config = config

-    def list(self) -> list[str]:
+    def list(self) -> builtins.list[str]:


ty is opinionated about this. astral-sh/ty#2035

kracekumar · 2025-12-19T23:37:41Z

litecli/sqlcompleter.py

        fuzzy: bool = True,
        casing: str | None = None,
-        punctuations: str = "most_punctuations",
+        punctuations: LAST_WORD_INCLUDE_TYPE = "most_punctuations",


Since the puncutations value is literal and here it was declared as str, ty complains about it. hence use the same type here.

kracekumar · 2025-12-21T01:39:07Z

litecli/completion_refresher.py

-            callbacks = [callbacks]
+            callbacks_list: list[Callable] = [callbacks]
+        else:
+            callbacks_list = list(cast(list[Callable], callbacks))


ty was complaining about this, hence modified it.

This is weird. Wouldn't this work?

callbacks_list = ist(callbacks)

Unfortunately no: https://play.ty.dev/0c4ac49a-58d7-4032-8d4b-453fc395b34a :-(

kracekumar · 2025-12-21T01:45:34Z

litecli/main.py

 from .sqlcompleter import SQLCompleter
 from .sqlexecute import SQLExecute

-click.disable_unicode_literals_warning = True


This is no longer needed in Python 3.9

kracekumar · 2025-12-21T01:49:23Z

litecli/packages/special/__init__.py

+    write_once,
+    write_pipe_once,
+    close_tee,
+)


There may be scope to improve over all import systems.

kracekumar · 2025-12-21T01:55:06Z

tests/__init__.py

@@ -0,0 +1 @@
+


To use relative imports in tests, added init.py file. Rather than using from utils import xyzuse from .utils import xyz.

kracekumar · 2025-12-21T01:55:33Z

tests/test_clistyle.py

    style = style_factory("default", cli_style)

-    assert isinstance(style(), Style)
+    assert isinstance(style, Style)


Not sure why this wasn't caught earlier.

kracekumar · 2025-12-21T01:56:00Z

tests/test_dbspecial.py

+        (".import ./data.csv ", 2),
+        (".import ./data.csv t", 2),
+        (".import ./data.csv `t", 2),
+        ('.import ./data.csv "t', 2),


Making it as tuple is easier to annotate the types.

kracekumar · 2025-12-21T01:56:19Z

tests/test_dbspecial.py

+        ("598244", "6 days 22 hours 10 min 44 sec"),
+        ("522600", "6 days 1 hour 10 min 0 sec"),
+    ]:
+        assert human_readable_text == format_uptime(seconds)


Just making it easier.

kracekumar · 2025-12-21T01:57:08Z

tests/test_main.py

            return ["test"]

-    class PromptBuffer:
+    class PromptBuffer(PromptSession):


This is to satisfy ty. Since PromptSession contains output attribute.

kracekumar · 2025-12-21T01:57:41Z

tests/test_main.py


 def test_startup_commands(executor):
    m = LiteCli(liteclirc=default_config_file)
+    assert m.startup_commands


This is to ensure, later access satisfies type checker.

kracekumar · 2025-12-21T02:15:47Z

There are some more generic Python typing improvements that are possible. I can send a separate PR later.

Can you take a look the changes @amjith @rolandwalker ? Thank you!

kracekumar added 4 commits December 17, 2025 23:41

Add the version to get ty working

3c4b677

remove unused import

9c6b498

Make ty pass all the type hints

455a2a2

Move ty to dev dependencies

7dcbf49

kracekumar changed the title ~~[WIP - Do Not Merge]: Add the version to get ty working~~ [WIP - Do Not Merge]: Add ty type checking Dec 19, 2025

kracekumar commented Dec 19, 2025

View reviewed changes

kracekumar added 3 commits December 21, 2025 00:54

Remove mypy

d1f4b79

Add the missing __init__.py

3090920

Add ty ignore statement

96c86dd

kracekumar changed the title ~~[WIP - Do Not Merge]: Add ty type checking~~ Migrate typechecking to ty Dec 21, 2025

kracekumar added 2 commits December 21, 2025 01:21

Çhange all the references of mypy to ty

2489a14

Make ty: ignore to type: ignore

30eb4ba

kracekumar commented Dec 21, 2025

View reviewed changes

kracekumar added 2 commits December 21, 2025 02:16

fix typo

7c6daf3

Use generator over Iterable

05022e6

kracekumar requested a review from amjith December 21, 2025 14:22

amjith approved these changes Dec 22, 2025

View reviewed changes

kracekumar merged commit eea974f into main Dec 22, 2025
8 checks passed

kracekumar deleted the krace/ty branch December 22, 2025 19:16

Migrate typechecking to ty #242

Migrate typechecking to ty #242

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kracekumar commented Dec 21, 2025

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kracekumar commented Dec 17, 2025 •

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