The example of form-based login could lead some users to think its authentication result
check was final. See https://stackoverflow.com/a/54410966/939364
This change should make it more obvious that users are expected to implement their
own logic to check whether authentication worked or not.
Websites that return a wrong ``Content-Length`` header may cause a data
loss error. Also when a chunked response is not finished properly.
This change adds a new setting ``DOWNLOAD_FAIL_ON_DATALOSS`` (default:
``True``) and request.meta key ``download_fail_on_dataloss``.
* add flags to request
* fxi test - add flags to request
* fix test(2) - add flags to request
* fix test(2) - add flags to request
* Updated test to reqser with flags field of request
* Updated documntation with flags field of request
* fix test identation
* fix test failed
* make the change backward comptaible
* remove unrequired spaces, fix documentation request flags
* remove unrequired space
* fx assert equal
* flags default is empty list
* Add flags to request
* add flags to request
* fxi test - add flags to request
* fix test(2) - add flags to request
* fix test(2) - add flags to request
* Updated test to reqser with flags field of request
* Updated documntation with flags field of request
* fix test identation
* fix test failed
* make the change backward comptaible
* remove unrequired spaces, fix documentation request flags
* remove unrequired space
* fx assert equal
* flags default is empty list
* add flags to request squashed commits
This can make the spider fail due to incorrect values being posted
server-side, which is extremely hard to debug because it is easy
to miss leading/trailing whitespace, even with a logging proxy.
The fix was merged for lxml 3.8 in lxml/lxml#228 so document that
as well.