Make uv lockfiles with local find_links portable across checkouts

docs/notes/2.34.x.md

@@ -115,6 +115,8 @@ Fixed a bug that could cause tool execution to fail when resolving the tool from
 
 Required named indexes to be referenced explicitly in requirement sources when using the uv resolver, to match the pex resolver's behavior.
 
+Local `[python-repos].find_links` directories under the buildroot no longer tie `uv` lockfiles to one checkout: they are now recorded as buildroot-relative paths. Builds using wheels from such directories also now get the same cache keys across checkouts and machines.
+
 Sidecar lockfile metadata files (`*.lock.metadata`, written when `[python].separate_lockfile_metadata_file` is enabled) now end with a trailing newline. The bundled tool metadata files have been updated accordingly, so regenerating them no longer produces a spurious diff.
 
 Interpreter constraints can now select a specific CPython ABI, to distinguish the free-threaded (no-GIL) build from the standard build. Qualify the interpreter type using either a PEP 508 extra, `CPython[free-threaded]` or `CPython[gil]`, or the equivalent `CPython+t` / `CPython-t` spellings. Both spellings are adopted from Pex. For example, `interpreter_constraints=["CPython[free-threaded]==3.14.*"]` matches only free-threaded 3.14 interpreters, while `CPython==3.14.*` continues to match either ABI.

src/python/pants/backend/python/goals/lockfile.py

@@ -6,7 +6,7 @@
 import itertools
 import os.path
 from collections import defaultdict
-from dataclasses import dataclass
+from dataclasses import dataclass, replace
 from operator import itemgetter
 from typing import cast
 
@@ -43,7 +43,12 @@
     load_lockfile,
     strip_comments_from_pex_json_lockfile,
 )
-from pants.backend.python.util_rules.uv import UvEnvironment, generate_pyproject_toml
+from pants.backend.python.util_rules.uv import (
+    UvEnvironment,
+    generate_pyproject_toml,
+    relativize_local_find_links,
+)
+from pants.base.build_root import BuildRoot
 from pants.base.glob_match_error_behavior import GlobMatchErrorBehavior
 from pants.core.goals.generate_lockfiles import (
     DEFAULT_TOOL_LOCKFILE,
@@ -351,6 +356,7 @@ async def generate_uv_lockfile(
     generate_lockfiles_subsystem: GenerateLockfilesSubsystem,
     downloaded_uv: DownloadedUv,
     uv_env: UvEnvironment,
+    buildroot: BuildRoot,
     level: LogLevel,
 ) -> GenerateLockfileResult:
     if not req.interpreter_constraints:
@@ -364,12 +370,18 @@ async def generate_uv_lockfile(
     )
     resolve_config.validate_for_uv(req.resolve_name)
 
+    resolve_find_links, resolve_local_find_links_globs = relativize_local_find_links(
+        resolve_config.find_links, buildroot.path
+    )
+    extra_find_links, extra_local_find_links_globs = relativize_local_find_links(
+        req.find_links, buildroot.path
+    )
     pyproject_content = generate_pyproject_toml(
         req.resolve_name,
         req.interpreter_constraints,
         req.requirements,
         indexes=resolve_config.indexes,
-        find_links=(*resolve_config.find_links, *req.find_links),
+        find_links=(*resolve_find_links, *extra_find_links),
         sources=resolve_config.sources,
     )
 
@@ -408,7 +420,7 @@ async def generate_uv_lockfile(
             # is generated.
             pass
 
-    uv_config = resolve_config.uv_config()
+    uv_config = replace(resolve_config, find_links=resolve_find_links).uv_config()
 
     uv_config_digest = await create_digest(
         CreateDigest(
@@ -418,9 +430,13 @@ async def generate_uv_lockfile(
             ]
         )
     )
-
+    find_links_digest = await path_globs_to_digest(
+        PathGlobs((*resolve_local_find_links_globs.globs, *extra_local_find_links_globs.globs))
+    )
     input_digest = await merge_digests(
-        MergeDigests([downloaded_uv.digest, uv_config_digest, existing_uv_lock_digest])
+        MergeDigests(
+            [downloaded_uv.digest, uv_config_digest, existing_uv_lock_digest, find_links_digest]
+        )
     )
 
     result = await execute_process_or_raise(

src/python/pants/backend/python/util_rules/pex.py

@@ -724,6 +724,9 @@ async def _setup_pex_requirements(
             concurrency_available,
         )
 
+    if not reqs_info.req_strings:
+        return _BuildPexRequirementsSetup([], [], concurrency_available)
+
     # We use pip to perform a normal resolve.
     digests = []
     argv = [

src/python/pants/backend/python/util_rules/pex_test.py

@@ -950,6 +950,9 @@ def assert_setup(
         ),
     )
 
+    # Nothing to resolve, so no repository args that could make the cache key path-dependent.
+    assert_setup(PexRequirements(), _BuildPexRequirementsSetup([], [], 0))
+
     # Pex lockfile.
     assert_setup(
         EntireLockfile(lockfile_obj, complete_req_strings=reqs),

src/python/pants/backend/python/util_rules/uv.py

@@ -32,6 +32,7 @@
     determine_resolve_config,
     generate_uv_index_config,
 )
+from pants.base.build_root import BuildRoot
 from pants.core.util_rules import system_binaries
 from pants.core.util_rules.env_vars import environment_vars_subset
 from pants.core.util_rules.subprocess_environment import SubprocessEnvironmentVars
@@ -47,11 +48,13 @@
     CreateDigest,
     FileContent,
     MergeDigests,
+    PathGlobs,
 )
 from pants.engine.intrinsics import (
     create_digest,
     get_digest_contents,
     merge_digests,
+    path_globs_to_digest,
 )
 from pants.engine.pants_lock import pants_lock_bin
 from pants.engine.rules import collect_rules, concurrently, implicitly, rule
@@ -93,6 +96,35 @@ def append_only_caches(cls) -> FrozenDict[str, str]:
         return FrozenDict({cls.cache_name: cls.cache_dir})
 
 
+def relativize_local_find_links(
+    find_links: Iterable[str], buildroot: str
+) -> tuple[tuple[str, ...], PathGlobs]:
+    """Rewrite find-links dirs under the buildroot to buildroot-relative paths.
+
+    uv records find-links paths verbatim in uv.lock, so absolute paths would tie the lockfile (and
+    every process that consumes it) to one checkout location. Returns the rewritten find-links and
+    the globs for the files of those dirs, which must be in the uv process sandbox.
+    """
+    rewritten: list[str] = []
+    local_globs: list[str] = []
+    for find_link in find_links:
+        if find_link.startswith("file://"):
+            path = find_link[len("file://") :]
+        elif os.path.isabs(find_link):
+            path = find_link
+        else:
+            rewritten.append(find_link)
+            continue
+        path = os.path.normpath(path)
+        if os.path.isabs(path) and os.path.commonpath((path, buildroot)) == buildroot:
+            relative_dir = os.path.relpath(path, buildroot)
+            rewritten.append(relative_dir)
+            local_globs.append(os.path.join(relative_dir, "*"))
+        else:
+            rewritten.append(find_link)
+    return tuple(rewritten), PathGlobs(local_globs)
+
+
 @dataclass(frozen=True)
 class UvEnvironment:
     env: FrozenDict[str, str]
@@ -189,6 +221,7 @@ async def create_venv_repository_from_uv_lockfile(
     realpath_binary: RealpathBinary,
     rm_binary: RmBinary,
     maybe_flock_binary: MaybeFlockBinary,
+    buildroot: BuildRoot,
     level: LogLevel,
 ) -> VenvRepository:
     """Install all packages from a uv lockfile into a virtualenv."""
@@ -209,6 +242,9 @@ async def create_venv_repository_from_uv_lockfile(
         ResolveConfigRequest(metadata.resolve), **implicitly()
     )
 
+    find_links, local_find_links_globs = relativize_local_find_links(
+        resolve_config.find_links, buildroot.path
+    )
     pyproject_content = generate_pyproject_toml(
         metadata.resolve,
         metadata.valid_for_interpreter_constraints,
@@ -222,7 +258,7 @@ async def create_venv_repository_from_uv_lockfile(
         # they don't involve auth, so they are not strictly needed after lockfile generation.
         # TODO: Get rid of "extra find_links" entirely, and simply hard-code an explicit
         #  source for pants_requirements.
-        find_links=resolve_config.find_links,
+        find_links=find_links,
         sources=resolve_config.sources,
     )
 
@@ -238,8 +274,9 @@ async def create_venv_repository_from_uv_lockfile(
         ),
         get_digest_contents(request.lockfile.lockfile_digest),
     )
-    uv_lock_digest = await create_digest(
-        CreateDigest([FileContent("uv.lock", uv_lock_contents[0].content)])
+    uv_lock_digest, find_links_digest = await concurrently(
+        create_digest(CreateDigest([FileContent("uv.lock", uv_lock_contents[0].content)])),
+        path_globs_to_digest(local_find_links_globs),
     )
 
     input_digest = await merge_digests(
@@ -248,6 +285,7 @@ async def create_venv_repository_from_uv_lockfile(
                 downloaded_uv.digest,
                 uv_config_digest,
                 uv_lock_digest,
+                find_links_digest,
             )
         )
     )
@@ -265,6 +303,7 @@ async def create_venv_repository_from_uv_lockfile(
     entropy.update((request.uv_platform or "").encode())
     entropy.update(b"\0")
     entropy.update(input_digest.fingerprint.encode())
+    entropy.update(b"\0UV_NO_INSTALLER_METADATA=1")
     venv_path_suffix = entropy.hexdigest()
 
     uv_cmd = shlex.join(
@@ -343,7 +382,7 @@ async def create_venv_repository_from_uv_lockfile(
         creation_subprocess=Subprocess(
             command=command,
             input_digest=input_digest,
-            env=uv_env.env,
+            env=FrozenDict({**uv_env.env, "UV_NO_INSTALLER_METADATA": "1"}),
             append_only_caches={
                 **downloaded_uv.append_only_caches(),
                 **VenvRepository.append_only_caches(),