Message-ID: <CAJ-ks9kj-RGbWh8uPxayQnpZU4E5WSY_X_SA7f3fKzZKC=ARVg@mail.gmail.com>
Date: Fri, 9 Jan 2026 18:07:33 -0500
From: Tamir Duberstein <tamird@...il.com>
To: y.j3ms.n@...il.com
Cc: Miguel Ojeda <ojeda@...nel.org>, Boqun Feng <boqun.feng@...il.com>, Gary Guo <gary@...yguo.net>, 
	Björn Roy Baron <bjorn3_gh@...tonmail.com>, 
	Benno Lossin <lossin@...nel.org>, Andreas Hindborg <a.hindborg@...nel.org>, 
	Alice Ryhl <aliceryhl@...gle.com>, Trevor Gross <tmgross@...ch.edu>, 
	Danilo Krummrich <dakr@...nel.org>, rust-for-linux@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/2] scripts: generate_rust_analyzer: add versioning infrastructure

On Fri, Jan 9, 2026 at 5:10 PM Jesung Yang via B4 Relay
<devnull+y.j3ms.n.gmail.com@...nel.org> wrote:
>
> From: Jesung Yang <y.j3ms.n@...il.com>
>
> Introduce multi-version support for rust-analyzer. The script now
> executes `rust-analyzer --version` to query the version string and
> generates a `rust-project.json` file compatible with the detected
> version.
>
> This is a preparatory patch to address inherent method resolution
> failures for primitive types occurring in rust-analyzer v0.3.2693
> (2025-11-24) or later when used with our current `rust-project.json`
> generation logic. Since the actual fix requires a feature only available
> in rust-analyzer v0.3.2727 (2025-12-22) or later, this infrastructure is
> necessary to avoid breaking compatibility with rust-analyzer v0.3.1940
> (2024-04-29), which corresponds to our MSRV of 1.78.
>
> Signed-off-by: Jesung Yang <y.j3ms.n@...il.com>

I think we can get all the information we need about the compiler
without shelling out to RA here. In KConfig we already have options
like

config RUSTC_HAS_COERCE_POINTEE
  def_bool RUSTC_VERSION >= 108400

and those configs all flow through scripts/generate_rust_analyzer.py.
Could we add one to indicate the new version of RA, and then drive the
logic from it?

> ---
>  scripts/generate_rust_analyzer.py | 181 +++++++++++++++++++++++++++++++++-----
>  1 file changed, 157 insertions(+), 24 deletions(-)
>
> diff --git a/scripts/generate_rust_analyzer.py b/scripts/generate_rust_analyzer.py
> index 147d0cc940681426771db865bc2462e7029a6d7d..32b0da99f17549ecc83e9a68911373310a2c9617 100755
> --- a/scripts/generate_rust_analyzer.py
> +++ b/scripts/generate_rust_analyzer.py
> @@ -4,10 +4,13 @@
>  """
>
>  import argparse
> +from datetime import datetime
> +import enum
>  import json
>  import logging
>  import os
>  import pathlib
> +import re
>  import subprocess
>  import sys
>
> @@ -19,7 +22,7 @@ def args_crates_cfgs(cfgs):
>
>      return crates_cfgs
>
> -def generate_crates(srctree, objtree, sysroot_src, external_src, cfgs, core_edition):
> +def generate_crates(ctx, srctree, objtree, sysroot_src, external_src, cfgs, core_edition):
>      # Generate the configuration list.
>      cfg = []
>      with open(objtree / "include" / "generated" / "rustc_cfg") as fd:
> @@ -35,7 +38,7 @@ def generate_crates(srctree, objtree, sysroot_src, external_src, cfgs, core_edit
>      crates_indexes = {}
>      crates_cfgs = args_crates_cfgs(cfgs)
>
> -    def append_crate(display_name, root_module, deps, cfg=[], is_workspace_member=True, is_proc_macro=False, edition="2021"):
> +    def append_crate(display_name, root_module, deps, cfg=[], crate_attrs=[], is_workspace_member=True, is_proc_macro=False, edition="2021"):
>          crate = {
>              "display_name": display_name,
>              "root_module": str(root_module),
> @@ -48,6 +51,8 @@ def generate_crates(srctree, objtree, sysroot_src, external_src, cfgs, core_edit
>                  "RUST_MODFILE": "This is only for rust-analyzer"
>              }
>          }
> +        if ctx["use_crate_attrs"] and len(crate_attrs) > 0:
> +            crate["crate_attrs"] = crate_attrs
>          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", "-"],
> @@ -72,52 +77,58 @@ def generate_crates(srctree, objtree, sysroot_src, external_src, cfgs, core_edit
>              edition=edition,
>          )
>
> -    # NB: sysroot crates reexport items from one another so setting up our transitive dependencies
> -    # here is important for ensuring that rust-analyzer can resolve symbols. The sources of truth
> -    # for this dependency graph are `(sysroot_src / crate / "Cargo.toml" for crate in crates)`.
> -    append_sysroot_crate("core", [], cfg=crates_cfgs.get("core", []), edition=core_edition)
> -    append_sysroot_crate("alloc", ["core"])
> -    append_sysroot_crate("std", ["alloc", "core"])
> -    append_sysroot_crate("proc_macro", ["core", "std"])
> +    def sysroot_deps(*deps):
> +        return list(deps) if ctx["add_sysroot_crates"] else []
> +
> +    if ctx["add_sysroot_crates"]:
> +        # NB: sysroot crates reexport items from one another so setting up our transitive dependencies
> +        # here is important for ensuring that rust-analyzer can resolve symbols. The sources of truth
> +        # for this dependency graph are `(sysroot_src / crate / "Cargo.toml" for crate in crates)`.
> +        append_sysroot_crate("core", [], cfg=crates_cfgs.get("core", []), edition=core_edition)
> +        append_sysroot_crate("alloc", ["core"])
> +        append_sysroot_crate("std", ["alloc", "core"])
> +        append_sysroot_crate("proc_macro", ["core", "std"])
>
>      append_crate(
>          "compiler_builtins",
>          srctree / "rust" / "compiler_builtins.rs",
>          [],
> +        crate_attrs=["no_std"],
>      )
>
>      append_crate(
>          "proc_macro2",
>          srctree / "rust" / "proc-macro2" / "lib.rs",
> -        ["core", "alloc", "std", "proc_macro"],
> +        sysroot_deps("core", "alloc", "std", "proc_macro"),
>          cfg=crates_cfgs["proc_macro2"],
>      )
>
>      append_crate(
>          "quote",
>          srctree / "rust" / "quote" / "lib.rs",
> -        ["alloc", "proc_macro", "proc_macro2"],
> +        sysroot_deps("alloc", "proc_macro") + ["proc_macro2"],
>          cfg=crates_cfgs["quote"],
>      )
>
>      append_crate(
>          "syn",
>          srctree / "rust" / "syn" / "lib.rs",
> -        ["proc_macro", "proc_macro2", "quote"],
> +        sysroot_deps("proc_macro") + ["proc_macro2", "quote"],
>          cfg=crates_cfgs["syn"],
>      )
>
>      append_crate(
>          "macros",
>          srctree / "rust" / "macros" / "lib.rs",
> -        ["std", "proc_macro", "proc_macro2", "quote", "syn"],
> +        sysroot_deps("std", "proc_macro") + ["proc_macro2", "quote", "syn"],
>          is_proc_macro=True,
>      )
>
>      append_crate(
>          "build_error",
>          srctree / "rust" / "build_error.rs",
> -        ["core", "compiler_builtins"],
> +        sysroot_deps("core") + ["compiler_builtins"],
> +        crate_attrs=["no_std"],
>      )
>
>      append_crate(
> @@ -125,31 +136,36 @@ def generate_crates(srctree, objtree, sysroot_src, external_src, cfgs, core_edit
>          srctree / "rust" / "pin-init" / "internal" / "src" / "lib.rs",
>          [],
>          cfg=["kernel"],
> +        crate_attrs=["no_std"],
>          is_proc_macro=True,
>      )
>
>      append_crate(
>          "pin_init",
>          srctree / "rust" / "pin-init" / "src" / "lib.rs",
> -        ["core", "pin_init_internal", "macros"],
> +        sysroot_deps("core") + ["pin_init_internal", "macros"],
>          cfg=["kernel"],
> +        crate_attrs=["no_std"],
>      )
>
>      append_crate(
>          "ffi",
>          srctree / "rust" / "ffi.rs",
> -        ["core", "compiler_builtins"],
> +        sysroot_deps("core") + ["compiler_builtins"],
> +        crate_attrs=["no_std"],
>      )
>
>      def append_crate_with_generated(
>          display_name,
>          deps,
> +        crate_attrs=[]
>      ):
>          append_crate(
>              display_name,
>              srctree / "rust"/ display_name / "lib.rs",
>              deps,
>              cfg=cfg,
> +            crate_attrs=crate_attrs
>          )
>          crates[-1]["env"]["OBJTREE"] = str(objtree.resolve(True))
>          crates[-1]["source"] = {
> @@ -160,9 +176,21 @@ def generate_crates(srctree, objtree, sysroot_src, external_src, cfgs, core_edit
>              "exclude_dirs": [],
>          }
>
> -    append_crate_with_generated("bindings", ["core", "ffi", "pin_init"])
> -    append_crate_with_generated("uapi", ["core", "ffi", "pin_init"])
> -    append_crate_with_generated("kernel", ["core", "macros", "build_error", "pin_init", "ffi", "bindings", "uapi"])
> +    append_crate_with_generated(
> +        "bindings",
> +        sysroot_deps("core") + ["ffi", "pin_init"],
> +        crate_attrs=["no_std"],
> +    )
> +    append_crate_with_generated(
> +        "uapi",
> +        sysroot_deps("core") + ["ffi", "pin_init"],
> +        crate_attrs=["no_std"],
> +    )
> +    append_crate_with_generated(
> +        "kernel",
> +        sysroot_deps("core") + ["macros", "build_error", "pin_init", "ffi", "bindings", "uapi"],
> +        crate_attrs=["no_std"],
> +    )
>
>      def is_root_crate(build_file, target):
>          try:
> @@ -190,12 +218,103 @@ def generate_crates(srctree, objtree, sysroot_src, external_src, cfgs, core_edit
>              append_crate(
>                  name,
>                  path,
> -                ["core", "kernel"],
> +                sysroot_deps("core") + ["kernel"],
>                  cfg=cfg,
> +                crate_attrs=["no_std"]
>              )
>
>      return crates
>
> +@...m.unique
> +class RaVersion(enum.Enum):
> +    """
> +    Represents rust-analyzer compatibility baselines. Concrete versions are mapped to the most
> +    recent baseline they have reached. Must be in release order.
> +    """
> +
> +    # v0.3.1940, released on 2024-04-29; bundled with the rustup 1.78 toolchain.
> +    V20240429 = 0
> +
> +    @staticmethod
> +    def baselines():
> +        assert len(RaVersion) == 1, "Exhaustiveness check: update baseline list!"
> +
> +        return [
> +            (datetime.strptime("2024-04-29", "%Y-%m-%d"), (0, 3, 1940), RaVersion.V20240429),
> +        ]
> +
> +    @staticmethod
> +    def default():
> +        # The default is the 2024-04-29 release, aligning with our MSRV policy.
> +        return RaVersion.V20240429
> +
> +    def __str__(self):
> +        assert len(RaVersion) == 1, "Exhaustiveness check: update if branches!"
> +
> +        if self == RaVersion.V20240429:
> +            return "v0.3.1940 (2024-04-29)"
> +        else:
> +            assert False, "Unreachable"
> +
> +def generate_rust_project(
> +    ra_version,
> +    srctree,
> +    objtree,
> +    sysroot,
> +    sysroot_src,
> +    external_src,
> +    cfgs,
> +    core_edition
> +):
> +    assert len(RaVersion) == 1, "Exhaustiveness check: update if branches!"
> +
> +    if ra_version == RaVersion.V20240429:
> +        ctx = {
> +            "use_crate_attrs": False,
> +            "add_sysroot_crates": True,
> +        }
> +        return {
> +            "crates": generate_crates(ctx, srctree, objtree, sysroot_src, external_src, cfgs, core_edition),
> +            "sysroot": str(sysroot),
> +        }
> +    else:
> +        assert False, "Unreachable"
> +
> +def query_ra_version():
> +    try:
> +        # Use the rust-analyzer binary found in $PATH.
> +        ra_version_output = subprocess.check_output(
> +            ["rust-analyzer", "--version"],
> +            stdin=subprocess.DEVNULL,
> +        ).decode('utf-8').strip()
> +        return ra_version_output
> +    except FileNotFoundError:
> +        logging.warning("Failed to find rust-analyzer in $PATH")
> +        return None
> +
> +def map_ra_version_baseline(ra_version_output):
> +    checkpoints = reversed(RaVersion.baselines())
> +
> +    # First, attempt to resolve to our known checkpoint using the release date.
> +    # This covers patterns like "rust-analyzer 1.78.0 (9b00956e 2024-04-29)".
> +    date_match = re.search(r"\d{4}-\d{2}-\d{2}", ra_version_output)
> +    if date_match:
> +        found_date = datetime.strptime(date_match.group(), "%Y-%m-%d")
> +        for date, ver, enum in checkpoints:
> +            if found_date >= date:
> +                return enum
> +
> +    # Otherwise, attempt to resolve to our known checkpoint using the rust-analyzer version.
> +    # This covers patterns like "rust-analyzer 0.3.2743-standalone".
> +    version_match = re.search(r"\d+\.\d+\.\d+", ra_version_output)
> +    if version_match:
> +        found_version = tuple(map(int, version_match.group().split(".")))
> +        for date, ver, enum in checkpoints:
> +            if found_version >= ver:
> +                return enum
> +
> +    return RaVersion.default()
> +
>  def main():
>      parser = argparse.ArgumentParser()
>      parser.add_argument('--verbose', '-v', action='store_true')
> @@ -216,10 +335,24 @@ def main():
>      # Making sure that the `sysroot` and `sysroot_src` belong to the same toolchain.
>      assert args.sysroot in args.sysroot_src.parents
>
> -    rust_project = {
> -        "crates": generate_crates(args.srctree, args.objtree, args.sysroot_src, args.exttree, args.cfgs, args.core_edition),
> -        "sysroot": str(args.sysroot),
> -    }
> +    output = query_ra_version()
> +    if output:
> +        compatible_ra_version = map_ra_version_baseline(output)
> +    else:
> +        default = RaVersion.default()
> +        logging.warning("Falling back to `rust-project.json` for rust-analyzer %s", default)
> +        compatible_ra_version = default
> +
> +    rust_project = generate_rust_project(
> +        compatible_ra_version,
> +        args.srctree,
> +        args.objtree,
> +        args.sysroot,
> +        args.sysroot_src,
> +        args.exttree,
> +        args.cfgs,
> +        args.core_edition,
> +    )
>
>      json.dump(rust_project, sys.stdout, sort_keys=True, indent=4)
>
>
> --
> 2.47.3
>
>

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