[PATCH 1/3] scripts: generate_rust_analyzer.py: add type hints

[Tamir Duberstein <tamird@gmail.com>]

Python type hints allow static analysis tools like mypy to detect type
errors during development, improving the developer experience.

Python type hints have been present in the kernel since 2019 at the
latest; see commit 6ebf5866f2e8 ("kunit: tool: add Python wrappers for
running KUnit tests").

Run `uv tool run mypy --strict scripts/generate_rust_analyzer.py` to
verify.

Signed-off-by: Tamir Duberstein <tamird@gmail.com>
---
 scripts/generate_rust_analyzer.py | 83 ++++++++++++++++++++++++++++-----------
 1 file changed, 61 insertions(+), 22 deletions(-)

diff --git a/scripts/generate_rust_analyzer.py b/scripts/generate_rust_analyzer.py
index aa8ea1a4dbe5..28ab05de52b8 100755
--- a/scripts/generate_rust_analyzer.py
+++ b/scripts/generate_rust_analyzer.py
@@ -10,8 +10,9 @@ import os
 import pathlib
 import subprocess
 import sys
+import typing as T
 
-def args_crates_cfgs(cfgs):
+def args_crates_cfgs(cfgs: T.Iterable[str]) -> dict[str, list[str]]:
     crates_cfgs = {}
     for cfg in cfgs:
         crate, vals = cfg.split("=", 1)
@@ -19,7 +20,34 @@ def args_crates_cfgs(cfgs):
 
     return crates_cfgs
 
-def generate_crates(srctree, objtree, sysroot_src, external_src, cfgs):
+class Dependency(T.TypedDict):
+    crate: int
+    name: str
+
+class Source(T.TypedDict):
+    include_dirs: list[str]
+    exclude_dirs: list[str]
+
+class Crate(T.TypedDict):
+    display_name: str
+    root_module: str
+    is_workspace_member: bool
+    is_proc_macro: bool
+    deps: list[Dependency]
+    cfg: list[str]
+    edition: T.Literal["2021"]
+    env: dict[str, str]
+    # `NotRequired` would be better but was added in 3.11.
+    proc_macro_dylib_path: T.Optional[str]
+    source: T.Optional[Source]
+
+def generate_crates(
+    srctree: pathlib.Path,
+    objtree: pathlib.Path,
+    sysroot_src: pathlib.Path,
+    external_src: pathlib.Path,
+    cfgs: list[str],
+) -> list[Crate]:
     # Generate the configuration list.
     cfg = []
     with open(objtree / "include" / "generated" / "rustc_cfg") as fd:
@@ -31,31 +59,40 @@ def generate_crates(srctree, objtree, sysroot_src, external_src, cfgs):
     # Now fill the crates list -- dependencies need to come first.
     #
     # Avoid O(n^2) iterations by keeping a map of indexes.
-    crates = []
-    crates_indexes = {}
+    crates: list[Crate] = []
+    crates_indexes: dict[str, int] = {}
     crates_cfgs = args_crates_cfgs(cfgs)
 
-    def append_crate(display_name, root_module, deps, cfg=[], is_workspace_member=True, is_proc_macro=False):
-        crate = {
-            "display_name": display_name,
-            "root_module": str(root_module),
-            "is_workspace_member": is_workspace_member,
-            "is_proc_macro": is_proc_macro,
-            "deps": [{"crate": crates_indexes[dep], "name": dep} for dep in deps],
-            "cfg": cfg,
-            "edition": "2021",
-            "env": {
-                "RUST_MODFILE": "This is only for rust-analyzer"
-            }
-        }
+    def append_crate(
+        display_name: str,
+        root_module: pathlib.Path,
+        deps: list[str],
+        cfg: list[str] = [],
+        is_workspace_member: bool = True,
+        is_proc_macro: bool = False,
+    ) -> None:
+        proc_macro_dylib_path = None
         if is_proc_macro:
             proc_macro_dylib_name = subprocess.check_output(
                 [os.environ["RUSTC"], "--print", "file-names", "--crate-name", display_name, "--crate-type", "proc-macro", "-"],
                 stdin=subprocess.DEVNULL,
             ).decode('utf-8').strip()
-            crate["proc_macro_dylib_path"] = f"{objtree}/rust/{proc_macro_dylib_name}"
+            proc_macro_dylib_path = f"{objtree}/rust/{proc_macro_dylib_name}"
         crates_indexes[display_name] = len(crates)
-        crates.append(crate)
+        crates.append(
+            {
+                "display_name": display_name,
+                "root_module": str(root_module),
+                "is_workspace_member": is_workspace_member,
+                "is_proc_macro": is_proc_macro,
+                "deps": [{"crate": crates_indexes[dep], "name": dep} for dep in deps],
+                "cfg": cfg,
+                "edition": "2021",
+                "env": {"RUST_MODFILE": "This is only for rust-analyzer"},
+                "proc_macro_dylib_path": proc_macro_dylib_path,
+                "source": None,
+            }
+        )
 
     # First, the ones in `rust/` since they are a bit special.
     append_crate(
@@ -107,7 +144,7 @@ def generate_crates(srctree, objtree, sysroot_src, external_src, cfgs):
         "exclude_dirs": [],
     }
 
-    def is_root_crate(build_file, target):
+    def is_root_crate(build_file: pathlib.Path, target: str) -> bool:
         try:
             return f"{target}.o" in open(build_file).read()
         except FileNotFoundError:
@@ -116,7 +153,9 @@ def generate_crates(srctree, objtree, sysroot_src, external_src, cfgs):
     # Then, the rest outside of `rust/`.
     #
     # We explicitly mention the top-level folders we want to cover.
-    extra_dirs = map(lambda dir: srctree / dir, ("samples", "drivers"))
+    extra_dirs: T.Iterable[pathlib.Path] = map(
+        lambda dir: srctree / dir, ("samples", "drivers")
+    )
     if external_src is not None:
         extra_dirs = [external_src]
     for folder in extra_dirs:
@@ -139,7 +178,7 @@ def generate_crates(srctree, objtree, sysroot_src, external_src, cfgs):
 
     return crates
 
-def main():
+def main() -> None:
     parser = argparse.ArgumentParser()
     parser.add_argument('--verbose', '-v', action='store_true')
     parser.add_argument('--cfgs', action='append', default=[])

-- 
2.48.1