Fix pytype error when using adb_logcat_file_path in open

[ko1in1u]

Built-in function open was called with the wrong arguments [wrong-arg-types]

       Expected: (file: Union[_PathLike, bytes, int, str], ...)
Actually passed: (file: None, ...)
Attributes of protocol _PathLike are not implemented on None: __fspath__

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This change is 

[xpconanfan]

Reviewable status: 0 of 1 files reviewed, 1 unresolved discussion (waiting on @ko1in1u)

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mobly/controllers/android_device_lib/services/logcat.py line 196 at r1 (raw file):

    if not self._adb_logcat_file_obj:
      deadline = time.perf_counter() + CREATE_LOGCAT_FILE_TIMEOUT_SEC
      while not os.path.exists(self.adb_logcat_file_path):

this already make sure adb_logcat_file_path won't be None, no?

[ko1in1u]

Reviewable status: 0 of 1 files reviewed, 1 unresolved discussion (waiting on @ko1in1u)

mobly/controllers/android_device_lib/services/logcat.py line 196 at r1 (raw file):

    if not self._adb_logcat_file_obj:
      deadline = time.perf_counter() + CREATE_LOGCAT_FILE_TIMEOUT_SEC
      while not os.path.exists(self.adb_logcat_file_path):

this already make sure adb_logcat_file_path won't be None, no?

Yes, this is the place to assign value to adb_logcat_file_path. However, pytype isn't aware because it performs static analysis and cannot definitively track the runtime assignment of self.adb_logcat_file_path from None to a string based on external conditions.

[xpconanfan]

Reviewable status: 0 of 1 files reviewed, 1 unresolved discussion (waiting on @ko1in1u)

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mobly/controllers/android_device_lib/services/logcat.py line 196 at r1 (raw file):

Previously, ko1in1u (Kolin Lu) wrote…

Yes, this is the place to assign value to adb_logcat_file_path. However, pytype isn't aware because it performs static analysis and cannot definitively track the runtime assignment of self.adb_logcat_file_path from None to a string based on external conditions.

We should not add random checks for linter.

Either tell the linter to ignore this part, or make the assignment logic more explicit so linter stop complaining

[ko1in1u]

Reviewable status: 0 of 1 files reviewed, 1 unresolved discussion (waiting on @ko1in1u)

mobly/controllers/android_device_lib/services/logcat.py line 196 at r1 (raw file):

Previously, ko1in1u (Kolin Lu) wrote…
We should not add random checks for linter.

Either tell the linter to ignore this part, or make the assignment logic more explicit so linter stop complaining

Add in-line comment to disable the pytype error.