do not use template when locking

Author: aignas

python/uv/private/lock.bzl

@@ -65,7 +65,6 @@ _RunLockInfo = provider(
 def _lock_impl(ctx):
     args = ctx.attr.args
     srcs = ctx.files.srcs
-    existing_output = ctx.files.existing_output
     output = ctx.actions.declare_file(ctx.label.name + ".out")
 
     toolchain_info = ctx.toolchains[UV_TOOLCHAIN_TYPE]
@@ -114,10 +113,11 @@ def _lock_impl(ctx):
     lock_args.add("--output-file", output)
 
     progress_message = "Creating a requirements.txt with uv: //{}:{}".format(ctx.label.package, ctx.label.name)
-    if existing_output:
+    if ctx.files.existing_output:
         ctx.actions.run_shell(
-            command = "cp {src} {dst} && \"$@\"".format(
-                src = existing_output.path,
+            command = "{copy} {src} {dst} && \"$@\"".format(
+                copy = ctx.attr.copy_cmd,
+                src = ctx.files.existing_output[0].path,
                 dst = output.path,
             ),
             mnemonic = "PyRequirementsLockUv",
@@ -130,10 +130,7 @@ def _lock_impl(ctx):
         )
     else:
         ctx.actions.run_shell(
-            command = "\"$@\"".format(
-                src = ctx.files.existing_output[0].path,
-                dst = output.path,
-            ),
+            command = "\"$@\"",
             mnemonic = "PyRequirementsLockUv",
             inputs = srcs,
             outputs = [output],
@@ -171,6 +168,9 @@ _lock = rule(
             allow_files = True,
             doc = "Public, see the docs in the macro.",
         ),
+        "copy_cmd": attr.string(
+            mandatory = True,
+        ),
         "env": attr.string_dict(
             doc = "Public, see the docs in the macro.",
         ),
@@ -378,6 +378,11 @@ def lock(
         strip_extras = strip_extras,
         target_compatible_with = target_compatible_with,
         update_target = update_target,
+        # TODO @aignas 2025-03-17: consider using python to copy files?
+        copy_cmd = select({
+            "@platforms//os:windows": "copy /v",
+            "//conditions:default": "cp -v",
+        }),
         tags = [
             "local",
             "manual",