fix updating importCargoLock when lockFile is in the nix store

nix_update/eval.py

@@ -1,7 +1,8 @@
 import json
+import os
 from dataclasses import InitVar, dataclass, field
 from textwrap import dedent, indent
-from typing import Any, Dict, List, Optional
+from typing import Any, Dict, List, Literal, Optional
 from urllib.parse import ParseResult, urlparse
 
 from .errors import UpdateError
@@ -33,7 +34,7 @@ class Package:
     vendor_hash: Optional[str]
     vendor_sha256: Optional[str]
     cargo_deps: Optional[str]
-    cargo_lock: Optional[str]
+    cargo_lock: Optional[str | Literal[False]]
     npm_deps: Optional[str]
     tests: List[str]
     has_update_script: bool
@@ -112,7 +113,13 @@ in {{
   cargo_deps = pkg.cargoDeps.outputHash or null;
   cargo_lock =
     if pkg ? cargoDeps.lockFile then
-      (sanitizePosition {{ file = pkg.cargoDeps.lockFile; }}).file
+      let
+        inherit (pkg.cargoDeps) lockFile;
+        res = builtins.tryEval (sanitizePosition {{
+          file = lockFile;
+        }});
+      in
+      if res.success then res.value.file else false
     else
       null;
   npm_deps = pkg.npmDeps.outputHash or null;
@@ -144,5 +151,9 @@ def eval_attr(opts: Options) -> Package:
         raise UpdateError(
             f"Nix's builtins.parseDrvName could not parse the version from {package.name}"
         )
+    if package.cargo_lock and not os.path.realpath(package.cargo_lock).startswith(
+        opts.import_path
+    ):
+        package.cargo_lock = False
 
     return package

nix_update/update.py

@@ -9,7 +9,7 @@ import tomllib
 from concurrent.futures import ThreadPoolExecutor
 from os import path
 from pathlib import Path
-from typing import Dict, Optional, Tuple
+from typing import Dict, Literal, Optional, Tuple
 
 from .errors import UpdateError
 from .eval import Package, eval_attr
@@ -152,7 +152,7 @@ def update_cargo_deps_hash(opts: Options, filename: str, current_hash: str) -> N
     replace_hash(filename, current_hash, target_hash)
 
 
-def update_cargo_lock(opts: Options, filename: str, dst: str) -> None:
+def update_cargo_lock(opts: Options, filename: str, dst: str | Literal[False]) -> None:
     res = run(
         [
             "nix",
@@ -160,17 +160,30 @@ def update_cargo_lock(opts: Options, filename: str, dst: str) -> None:
             "--impure",
             "--print-out-paths",
             "--expr",
-            f'{get_package(opts)}.overrideAttrs (_: {{ prePatch = "cp -r . $out; exit"; outputs = [ "out" ]; }})',
+            f"""
+{get_package(opts)}.overrideAttrs (_: {{
+  cargoDeps = null;
+  postUnpack = ''
+    cp -r "$sourceRoot/Cargo.lock" $out
+    exit
+  '';
+  outputs = [ "out" ];
+}})
+""",
         ]
         + opts.extra_flags,
     )
-    src = Path(res.stdout.strip()) / "Cargo.lock"
+    src = Path(res.stdout.strip())
     if not src.is_file():
         return
 
-    shutil.copyfile(src, dst)
-    hashes = {}
-    with open(dst, "rb") as f:
+    with open(src, "rb") as f:
+        if dst:
+            with open(dst, "wb") as fdst:
+                shutil.copyfileobj(f, fdst)
+                f.seek(0)
+
+        hashes = {}
         lock = tomllib.load(f)
         regex = re.compile(r"git\+([^?]+)(\?(rev|tag|branch)=.*)?#(.*)")
         git_deps = {}
@@ -326,7 +339,7 @@ def update(opts: Options) -> Package:
         if package.cargo_deps:
             update_cargo_deps_hash(opts, package.filename, package.cargo_deps)
 
-        if package.cargo_lock:
+        if package.cargo_lock is not None:
             update_cargo_lock(opts, package.filename, package.cargo_lock)
 
         if package.npm_deps:

tests/test_cargo_lock_update.py

@@ -39,8 +39,6 @@ def test_main(helpers: conftest.Helpers) -> None:
             check=True,
         ).stdout.strip()
         print(diff)
-        assert "Cargo.lock" in diff
-        assert '+source = "git+' in diff
         assert (
             "https://github.com/charliermarsh/ruff/compare/v0.0.254...v0.0.255" in diff
         )

tests/testpkgs/cargo-lock-update/default.nix

@@ -12,7 +12,7 @@ rustPlatform.buildRustPackage rec {
   };
 
   cargoLock = {
-    lockFile = ./Cargo.lock;
+    lockFile = src + "/Cargo.lock";
     outputHashes = {
       "libcst-0.1.0" = "sha256-jG9jYJP4reACkFLrQBWOYH6nbKniNyFVItD0cTZ+nW0=";
       "libcst_derive-0.1.0" = "sha256-jG9jYJP4reACkFLrQBWOYH6nbKniNyFVItD0cTZ+nW0=";