Type checking by amjith · Pull Request #233 · dbcli/litecli

amjith · 2025-08-17T23:36:31Z

Description

Add mypy based type checking.

Thanks to @rolandwalker for adding type hints to mycli. I've used that as inspiration and reference to do the same for litecli.

Checklist

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

- Introduce packages/special/types.py with DBCursor Protocol - Add/ tighten type hints across special/, sqlcompleter, sqlexecute, clibuffer/toolbar/style, config, filepaths, lexer, completion_refresher, key_bindings - Remove remaining mypy ignore headers in special modules - Replace Any with concrete types where safe; improve TextIO handling - Fix utils.check_if_sqlitedotcommand to handle non-str inputs safely - Remove mycli references in comments and update docstrings - Minor refactors for clarity; ruff+mypy clean

…o implicit Optional, warn on Any). Note: run with --explicit-package-bases or via tox.

…py, and utils bug fix

…pline (Unreleased at top, succinct entries)

rolandwalker · 2025-08-18T09:55:42Z

litecli/clistyle.py

+from __future__ import annotations

 import logging
+from typing import Dict, List, Tuple


When using import annotations in Python 3.9, and for any later Python without the import, dict, list, and tuple can be used in their lowercased forms, without importing from typing.

rolandwalker · 2025-08-18T09:56:34Z

litecli/__init__.py

@@ -1,3 +1,6 @@
+# type: ignore


Why is this #type: ignore needed?

I had added mypy: ignore-errors to all the files before I started. Looks like I left them in by mistake.

rolandwalker · 2025-08-18T09:57:12Z

litecli/clitoolbar.py

@@ -1,17 +1,19 @@
-from __future__ import unicode_literals
+# mypy: ignore-errors


What is mypy: ignore-errors doing for us?

I had added mypy: ignore-errors to all the files before I started. Looks like I left them in by mistake.

rolandwalker · 2025-08-18T09:59:11Z

litecli/config.py



-def load_config(usr_cfg, def_cfg=None):
+def load_config(usr_cfg: str, def_cfg: Optional[str] = None) -> ConfigObj:


str | None is preferred by most over Optional[str].

rolandwalker · 2025-08-18T10:00:22Z

litecli/key_bindings.py

@@ -1,24 +1,31 @@
-from __future__ import unicode_literals


There are a few changes here unrelated to type hinting.

rolandwalker · 2025-08-18T10:03:50Z

litecli/packages/parseutils.py



-def last_word(text, include="alphanum_underscore"):
+def last_word(text: str, include: str = "alphanum_underscore") -> str:


The type of include could even be a Literal of the keys of cleanup_regex.

rolandwalker · 2025-08-18T10:07:49Z

litecli/packages/special/dbcommands.py

    case_sensitive=True,
 )
-def status(cur, **_):
+def status(cur: DBCursor, **_: Any) -> List[Tuple]:


As a matter of style, there isn't much purpose in typing **_: Any. But it does no harm.

rolandwalker · 2025-08-18T10:08:52Z

litecli/packages/special/iocommands.py


 @export
-def set_favorite_queries(config):
+def set_favorite_queries(config: Any) -> None:


Is Any the best we can do for config?

I was looking at mycli for this and it wasn't typed so I just went to Any.

rolandwalker

I would highly recommend replacing the capitalized versions of types with lowercased versions for builtins such as tuple. Python 3.9 will be EOL soon, and we even can remove from __future__ import annotations if support for 3.9 is removed.

Replace Dict, List, Tuple with dict, list, tuple. Replace Optional[str] with str | None.

kracekumar · 2025-08-26T23:22:35Z

I will take a look at this pr over the weekend.

kracekumar

lgtm as a first step to introduce the type hints. We can improve over time 👍🏾

kracekumar · 2025-08-31T21:21:57Z

litecli/clibuffer.py



-def cli_is_multiline(cli):
+def cli_is_multiline(cli: Any) -> Filter:


I understand sometimes types can be complicated to express so Any is preferred. Is it possible to add type here? If not documenting reason to use Any can be useful later to replace it with better type. I suspect cli by default is of the type, Any.

I'll have to come back to the use of Any and fix them up.

kracekumar · 2025-08-31T21:40:28Z

litecli/completion_refresher.py

            return [(None, None, None, "Auto-completion refresh restarted.")]
        else:
-            if executor.dbname == ":memory:":
+            if executor.dbname == ":memory":


This one seems non-type change.

Should we use something like executor.dbname.startswith(":memory")?

Good catch. I'll fix it.

I don't think we could use startswith() here. I think it has to be an exact match.

kracekumar · 2025-08-31T21:52:17Z

litecli/packages/prompt_utils.py

-    * False if the query is destructive and the user doesn't want to proceed.
+    def convert(self, value: bool | str, param: click.Parameter | None, ctx: click.Context | None) -> bool:
+        if isinstance(value, bool):
+            return bool(value)


We can just return value right like return value right?

kracekumar · 2025-08-31T22:04:57Z

tests/test_parseutils.py

@@ -1,3 +1,5 @@
+# mypy: ignore-errors


Is there a way to ignore all the errors in the directory rather than at each file in test directory?

amjith added 19 commits August 17, 2025 13:44

Add typechecking. 1/n

a864d36

Add typechecking. 2/n

618bebf

Add type hints to prompt_utils.

ce4c693

Add type hints to parse_utils.

bfbe8d4

Add types for filepaths and completion_engine.

d62f0f5

Type hints for packages/special files.

603f92f

Type hints for cli_* files.

ad1d5bf

Type hints for sqlcompleter.

80c6873

Type hints to config.py key_bindings.py and lexer.py

4205f70

Type hints for completion_refresher and sqlexecute

7988113

Type hint main.py and introduce DBCursor protocol.

3630c12

Centralize DBCursor. Remove ignore-errors.

0c1165e

Add DBCursor to types.py.

17b6e2a

More refinements to type checking.

a99c644

mypy: tighten config (3.9 target, disallow untyped/incomplete defs, n…

2337398

…o implicit Optional, warn on Any). Note: run with --explicit-package-bases or via tox.

changelog: document typing improvements, shared DBCursor, stricter my…

8a340b8

…py, and utils bug fix

docs(AGENTS): document test/lint/type-check flows and changelog disci…

fce2300

…pline (Unreleased at top, succinct entries)

Update changelog.

a88aa4a

amjith requested review from kracekumar and rolandwalker August 17, 2025 23:36

amjith added 4 commits August 17, 2025 16:41

Fix the workflow file syntax.

09f74d9

Add mypy to dev deps.

dbfa16b

Fix the workflow file.

624e6d5

Fix mypy.

1615778

rolandwalker reviewed Aug 18, 2025

View reviewed changes

rolandwalker approved these changes Aug 18, 2025

View reviewed changes

amjith added 5 commits August 23, 2025 11:14

Remove the mypy:ignore directive.

90eb1d8

Use modern python type hints.

a5350f0

Replace Dict, List, Tuple with dict, list, tuple. Replace Optional[str] with str | None.

Tighten the typehint for parseutils.

821f62b

Fix the remaining type hint issues.

058a84f

Merge branch 'main' into amjith/type-checking

39660bc

kracekumar approved these changes Aug 31, 2025

View reviewed changes

amjith added 2 commits September 28, 2025 13:39

Fix up a couple of PR comments.

c5e1a61

Merge branch 'main' into amjith/type-checking

31dea66

amjith merged commit 792263b into main Sep 28, 2025
8 checks passed

amjith deleted the amjith/type-checking branch September 28, 2025 20:56

		@@ -1,17 +1,19 @@
		from __future__ import unicode_literals
		# mypy: ignore-errors



		def load_config(usr_cfg, def_cfg=None):
		def load_config(usr_cfg: str, def_cfg: Optional[str] = None) -> ConfigObj:



		def last_word(text, include="alphanum_underscore"):
		def last_word(text: str, include: str = "alphanum_underscore") -> str:



		def cli_is_multiline(cli):
		def cli_is_multiline(cli: Any) -> Filter:

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amjith commented Aug 17, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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kracekumar commented Aug 26, 2025

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amjith commented Aug 17, 2025 •

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