kleaf: wrapper handles return code when running as subprocess

When the internal bazel binary is executed as a subprocess,
the return code from process.wait() is never checked. Wrap
it with a coroutine that actually checks the return code.

Test: integration test
Change-Id: Ifaa134658f823fab2dbf534092e84700fa9dc29c

2 files changed, 24 insertions, 1 deletions

diff --git a/kleaf/bazel.py b/kleaf/bazel.py
index 2aa7cb60..3ccaaba5 100755
--- a/kleaf/bazel.py
+++ b/kleaf/bazel.py
@@ -56,6 +56,13 @@ class BazelWrapperException(Exception):
         super().__init__(self, self.message)
 
 
+class BazelSubprocessException(BazelWrapperException):
+    """The internal `bazel` call fails."""
+
+    def __init__(self, code: int):
+        super().__init__(code=code)
+
+
 class MultipleBazelWrapperException(BazelWrapperException):
     """Wraps multiple BazelWrapperException into one."""
 
@@ -647,6 +654,13 @@ class OutputMutator:
             output_stream.flush()
 
 
+async def _wait_for_subprocess(process):
+    """Wraps process.wait() and raises if exit code is non-zero."""
+    return_code = await process.wait()
+    if return_code != 0:
+        raise BazelSubprocessException(code=return_code)
+
+
 async def run(command, env, epilog_coroutine, output_mutator):
     """Runs command with env asynchronously.
 
@@ -675,7 +689,7 @@ async def run(command, env, epilog_coroutine, output_mutator):
     coroutines = [
         stderr_coroutine,
         stdout_coroutine,
-        process.wait(),
+        _wait_for_subprocess(process),
     ]
     tasks = [asyncio.Task(coroutine) for coroutine in coroutines]
     done, _ = await asyncio.wait(tasks, return_when=asyncio.ALL_COMPLETED)
diff --git a/kleaf/tests/integration_test/integration_test.py b/kleaf/tests/integration_test/integration_test.py
index 021a8040..587db63c 100644
--- a/kleaf/tests/integration_test/integration_test.py
+++ b/kleaf/tests/integration_test/integration_test.py
@@ -622,6 +622,15 @@ class QuickIntegrationTest(KleafIntegrationTestBase):
         self._check_output("build", ["--nobuild", "--strip_execroot",
                                      "//build/kernel:hermetic-tools"])
 
+    def test_strip_execroot_error(self):
+        """Tests that if cmd with --strip_execroot fails, exit code is set."""
+        popen = self._popen("what",
+                            ["--strip_execroot"],
+                            stdout=subprocess.PIPE,
+                            stderr=subprocess.PIPE)
+        popen.communicate()
+        self.assertNotEqual(popen.returncode, 0)
+
 
 class ScmversionIntegrationTest(KleafIntegrationTestBase):