[PATCH 13/14] iotests: make qemu_img_log() check log level

[John Snow]

Improve qemu_img_log() to actually check if logging is turned on. If it
isn't, revert to the behavior of qemu_img(). This is done so that there
really is no way to avoid scrutinizing qemu-ing subprocess calls by
accident.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 tests/qemu-iotests/iotests.py | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
index f8d966cd73..6af503058f 100644
--- a/tests/qemu-iotests/iotests.py
+++ b/tests/qemu-iotests/iotests.py
@@ -318,7 +318,19 @@ def qemu_img_map(*args: str) -> Any:
     return qemu_img_json('map', "--output", "json", *args)
 
 def qemu_img_log(*args: str) -> subprocess.CompletedProcess[str]:
-    result = qemu_img(*args, check=False)
+    """
+    Logged, unchecked variant of qemu_img() that allows non-zero exit codes.
+
+    If logging is perceived to be disabled, this function will fall back
+    to prohibiting non-zero return codes.
+
+    :raise VerboseProcessError:
+        When the return code is negative, or when logging is disabled
+        on any non-zero return code.
+
+    :return: a CompletedProcess instance with returncode and console output.
+    """
+    result = qemu_img(*args, check=not logging_enabled())
     log(result.stdout, filters=[filter_testfiles])
     return result
 
@@ -1640,6 +1652,11 @@ def activate_logging():
     test_logger.setLevel(logging.INFO)
     test_logger.propagate = False
 
+def logging_enabled() -> bool:
+    """Return True if iotest logging is active."""
+    return (test_logger.hasHandlers()
+            and test_logger.getEffectiveLevel() >= logging.INFO)
+
 # This is called from script-style iotests without a single point of entry
 def script_initialize(*args, **kwargs):
     """Initialize script-style tests without running any tests."""
-- 
2.34.1