fix(tests): keep __pycache__ out of a clean checkout

.gitignore

@@ -1,6 +1,12 @@
 tests/tmp/
 plugin/
 
+# CPython writes these when a suite imports the hook's Python modules
+# (e.g. the activation probe); untracked but unignored, they dirty the
+# checkout after a green run (issue #897).
+__pycache__/
+*.pyc
+
 # opencode: @opencode-ai/plugin is a devDependency for typings only (issue
 # #319); node_modules/ is never imported at runtime and never ships (see
 # tests/build-plugin.sh, which copies only opencode/{index.js,package.json}).

tests/fixtures/test_rewrite_runtime.py

@@ -205,7 +205,11 @@ def prefix_fixture(self, body):
         spec = self.root / "prefix-fixture.json"
         spec.write_text(json.dumps({"profile": profile, "records": str(records.root)}))
         native = self.native.replace("'printf fixture'", shlex.quote(issued["command"]))
-        return [sys.executable, "-I", str(Path(__file__).resolve()), "--prefix-fixture", str(spec), native]
+        # -I ignores PYTHONDONTWRITEBYTECODE (it implies -E), and this
+        # reinvocation re-imports RUNTIME at module load before any guard in
+        # __main__ runs, so -B is required here to keep it from writing
+        # agentkit/hooks/lib/__pycache__ into the shipped tree (issue #897).
+        return [sys.executable, "-I", "-B", str(Path(__file__).resolve()), "--prefix-fixture", str(spec), native]
 
     def test_public_prefix_executes_once_with_native_result_and_refuses_replay(self):
         command = self.prefix_fixture('printf "%s|%s|%s\\n" "$PWD" "$1" "$2"\nprintf stderr >&2\nexit 37\n')

tests/run-tests.sh

@@ -27,6 +27,12 @@ pin_locale() {
 }
 pin_locale
 
+# Suites that import Python modules (e.g. the activation probe) write
+# __pycache__/ into the shipped tree unless bytecode writes are disabled.
+# Export it here so it reaches every suite subprocess and the probe stays
+# read-only (issue #897).
+export PYTHONDONTWRITEBYTECODE=1
+
 here=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)
 root=$(dirname -- "$here")
 # The plugin root holds both the skills and the hook dispatchers. The hooks are

tests/test-clean-tree-after-probe.sh

@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+# Pins issue #897: a suite that imports the hook's Python modules must never
+# leave __pycache__/ behind in the shipped tree. test-rewrite-runtime.sh's
+# --prefix-fixture reinvocation runs with `-I`, which implies `-E` and so
+# ignores PYTHONDONTWRITEBYTECODE; without an explicit -B on that reinvocation
+# it re-imports agentkit/hooks/lib/rewrite_runtime.py and writes
+# agentkit/hooks/lib/__pycache__/, dirtying an otherwise-clean checkout.
+set -uo pipefail
+
+TEST_NAME='clean tree after probe'
+here=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)
+root=$(dirname -- "$here")
+# shellcheck source=lib/assert.sh
+source "$here/lib/assert.sh"
+
+plugin="$root/agentkit"
+
+before=$(find "$plugin" -name '__pycache__' 2>/dev/null | LC_ALL=C sort)
+assert_eq '' "$before" 'no __pycache__ under agentkit/ before the suite runs'
+
+unset PYTHONDONTWRITEBYTECODE
+(cd -- "$here" && python3 -B fixtures/test_rewrite_runtime.py) > /dev/null 2>&1
+rc=$?
+assert_eq 0 "$rc" 'test_rewrite_runtime.py exits clean'
+
+after=$(find "$plugin" -name '__pycache__' 2>/dev/null | LC_ALL=C sort)
+assert_eq '' "$after" 'no __pycache__ under agentkit/ after running the rewrite-runtime fixture'
+
+finish