fix(uv): keep JDK paths valid during sdist builds

e2e/cases/BUILD.bazel

@@ -122,7 +122,7 @@ write_source_files(
         # plumbing for the augment-on-defaults `toolchains = [...]` /
         # `env = {...}`. The override layers a JDK runtime on top of the
         # default CC toolchain; the snapshot pins both toolchain
-        # references and both env families (CC + JAVA_HOME/JAVA/JAR).
+        # references and both env families (CC + JAVA_HOME/JAVA).
         # Pairs with the analysis test at
         # //uv/private/pep517_whl:toolchain_env_test which asserts the
         # rule expands env keys correctly given an explicit fixture.

e2e/cases/uv-sdist-jdk-build/setup.MODULE.bazel

@@ -1,7 +1,7 @@
 """Regression for the per-package toolchain plumbing on
 `uv.override_package`. jpype1 is forced to sdist via
 [tool.uv].no-binary-package; the override layers a JDK runtime
-toolchain into the build env so JAVA_HOME / JAVA / JAR are exported.
+toolchain into the build env so JAVA_HOME / JAVA are exported.
 
 Uses its own hub to keep the override and no-binary setting isolated
 from other test cases.
@@ -29,7 +29,6 @@ uv.unstable_annotate_packages(
 uv.override_package(
     name = "jpype1",
     env = {
-        "JAR": "$(JAVABASE)/bin/jar",
         "JAVA": "$(JAVA)",
         "JAVA_HOME": "$(JAVABASE)",
     },

uv/private/pep517_whl/BUILD.bazel

@@ -158,7 +158,6 @@ pep517_native_whl(
         "STRIP": "$(STRIP)",
         "JAVA_HOME": "$(JAVABASE)",
         "JAVA": "$(JAVA)",
-        "JAR": "$(JAVABASE)/bin/jar",
     },
     tags = ["manual"],
     tool = ":__stub_tool",

uv/private/pep517_whl/build_helper.py

@@ -97,6 +97,14 @@ def _override_tool(env, key, wrapper):
         env[key] = shlex.join(parts)
 
 
+def _absolutize_java_tool_paths(env):
+    """Keep Bazel's Java toolchain paths valid after the backend cwd change."""
+    for key in ("JAVA_HOME", "JAVA"):
+        value = env.get(key)
+        if value and not path.isabs(value) and path.exists(value):
+            env[key] = path.abspath(value)
+
+
 def _compiler_env(tmpdir):
     env = dict(os.environ)
     # The helper's launcher exports RUNFILES_DIR, RUNFILES_MANIFEST_FILE, and
@@ -121,6 +129,11 @@ def _compiler_env(tmpdir):
     env["TEMP"] = tmpdir
     env["TEMPDIR"] = tmpdir
 
+    # The Java toolchain expands its paths relative to the execroot. Resolve
+    # them while the helper still runs there; the PEP 517 backend later runs
+    # inside the unpacked source tree.
+    _absolutize_java_tool_paths(env)
+
     cc_path = _resolve_compiler_path(env, "CC", "cc")
     cxx_path = _resolve_compiler_path(env, "CXX", "c++")
 

uv/private/pep517_whl/test.bzl

@@ -54,7 +54,7 @@ hostile_python_env_target = rule(
 _CC_ENV_KEYS = ["CC", "CXX", "AR", "LD", "STRIP"]
 
 # Env vars sourced from the Java runtime toolchain's TemplateVariableInfo.
-_JDK_ENV_KEYS = ["JAVA_HOME", "JAVA", "JAR"]
+_JDK_ENV_KEYS = ["JAVA_HOME", "JAVA"]
 
 _REQUIRED_ENV_KEYS = _CC_ENV_KEYS + _JDK_ENV_KEYS
 
@@ -100,13 +100,6 @@ def _toolchain_env_test_impl(ctx):
         "CXX should use the declared companion or selected compiler fallback",
     )
 
-    # JAR is constructed from $(JAVABASE)/bin/jar — sanity-check the suffix.
-    asserts.true(
-        env,
-        action_env.get("JAR", "").endswith("/bin/jar"),
-        "JAR should resolve under JAVA_HOME/bin/jar; got {}".format(action_env.get("JAR")),
-    )
-
     return analysistest.end(env)
 
 pep517_native_whl_toolchain_env_test = analysistest.make(_toolchain_env_test_impl)

uv/private/pep517_whl/tests/explicit_env/BUILD.bazel

@@ -7,11 +7,15 @@ pep517_native_whl(
     src = "//uv/private/pep517_whl:__python_env_sdist",
     env = {
         "EXPECTED_PYTHONPATH": "/explicit/path",
+        "EXPECT_JAVA_TOOL_PATHS": "1",
+        "JAVA": "$(JAVA)",
+        "JAVA_HOME": "$(JAVABASE)",
         "PYTHONPATH": "/explicit/path",
     },
     # This must only build through the hostile environment transition below.
     tags = ["manual"],
     tool = "//uv/private/pep517_whl:__build_helper",
+    toolchains = ["@bazel_tools//tools/jdk:current_java_runtime"],
     version = "0.0.1",
 )
 

uv/private/pep517_whl/tests/python_env_backend/backend.py

@@ -37,6 +37,12 @@ def _check_environment() -> None:
     if os.environ.get("PYTHONSAFEPATH") != "1":
         raise RuntimeError("unrelated PYTHONSAFEPATH was not preserved")
 
+    if os.environ.get("EXPECT_JAVA_TOOL_PATHS") == "1":
+        for name in ("JAVA_HOME", "JAVA"):
+            value = os.environ.get(name)
+            if not value or not os.path.isabs(value) or not os.path.exists(value):
+                raise RuntimeError(f"{name} is not an absolute existing path: {value!r}")
+
 
 def get_requires_for_build_wheel(
     config_settings: dict[str, object] | None = None,