fix: Fix zipapp compression support for new py_zipapp_binary target (#3653)

The compression level isn't being correctly passed by the zipapp rule to
the zipper
program, resulting in an error if custom compression is specified.

To fix, pass the arg correctly to the zipper.

`venv_zipapp_test.py` is updated to also confirm zipapps are properly
compressed when configured in the BUILD target.

Fixes #3646

Author: nate-england

CHANGELOG.md

@@ -63,7 +63,8 @@ END_UNRELEASED_TEMPLATE
 
 {#v0-0-0-fixed}
 ### Fixed
-* Nothing fixed.
+* (zipapp) Resolve issue passing through compression settings in
+  `py_zippapp_binary` targets. ([#3646](https://github.com/bazel-contrib/rules_python/issues/3646))
 
 {#v0-0-0-added}
 ### Added

python/private/zipapp/py_zipapp_rule.bzl

@@ -112,7 +112,7 @@ def _create_zip(ctx, py_runtime, py_executable, stage2_bootstrap):
         format = "--legacy-external-runfiles=%s",
     )
     if ctx.attr.compression:
-        zipper_args.add(ctx.attr.compression, "--compression=%s")
+        zipper_args.add(ctx.attr.compression, format = "--compression=%s")
     zipper_args.add("--runfiles-dir=runfiles")
 
     actions_run(

tests/py_zipapp/BUILD.bazel

@@ -38,6 +38,27 @@ py_test(
     target_compatible_with = NOT_WINDOWS,
 )
 
+# Create the app with a supported level of compression
+py_zipapp_binary(
+    name = "venv_zipapp_compressed",
+    binary = ":venv_bin",
+    compression = "4",
+    target_compatible_with = NOT_WINDOWS,
+)
+
+py_test(
+    name = "venv_zipapp_compressed_test",
+    srcs = ["venv_zipapp_test.py"],
+    data = [":venv_zipapp_compressed"],
+    env = {
+        "BZLMOD_ENABLED": str(int(BZLMOD_ENABLED)),
+        "COMPRESSED": "1",
+        "TEST_ZIPAPP": "$(location :venv_zipapp_compressed)",
+    },
+    main = "venv_zipapp_test.py",
+    target_compatible_with = NOT_WINDOWS,
+)
+
 py_binary(
     name = "system_python_bin",
     srcs = ["main.py"],

tests/py_zipapp/venv_zipapp_test.py

@@ -71,6 +71,12 @@ def test_zipapp_structure(self):
         zipapp_path = os.environ["TEST_ZIPAPP"]
 
         with self._open_zipapp(zipapp_path) as zf:
+            info = zf.infolist()[0]
+            if os.getenv("COMPRESSED", "0") == "1":
+                self.assertEqual(info.compress_type, zipfile.ZIP_DEFLATED)
+            else:
+                self.assertEqual(info.compress_type, zipfile.ZIP_STORED)
+
             namelist = zf.namelist()
 
             if self._is_bzlmod_enabled():