ads-github-show-rate-limits: http response code not checked

[salewski]

The ads-github-show-rate-limits program is checking the exit status of the
curl subprocess, but is not arranging for the HTTP status code to be
available for consideration. This can lead to the program proceeding when it
really ought to stop, and (in at least one case) is also suppressing
information that should be displayed to the user. For example, enabling 2FA
for an account (see issue #42) but not configuring a GitHub personal access
code can cause the program to error out with the mysterious message:

    $ ads-github-show-rate-limits
    jq: error (at <stdin>:1): null (null) has no keys
    ads-github-show-rate-limits (error): was unable to extract rate limit data from GitHub service response; bailing out

Cranking up the trace output reveals that the GitHub v3 API attempted to convey
a helpful "Must specify two-factor authentication OTP code." message, but the
app did not notice so inadvertently suppressed it. The fat arrow shows where
the curl exit status is checked, and you can see that the program then
simply proceeds to feed the JSON response to jq without first checking the
HTTP response code.

    $ ads-github-show-rate-limits -vvv
    ...
    + printf 'ads-github-show-rate-limits (info): requesting /rate_limit\n'
    ads-github-show-rate-limits (info): requesting /rate_limit
    ++ /usr/bin/curl --silent --show-error --tlsv1.2 --proto https --proto-redir https --basic --netrc --user-agent ads-github-show-rate-limits --header 'Accept: application/vnd.github.v3+json' --get https://api.github.com/rate_limit
    + t_gh_json_service_response='{"message":"Must specify two-factor authentication OTP code.","documentation_url":"https://developer.github.com/v3/auth#working-with-two-factor-authentication"}'
=>  + test 0 -ne 0
    ++ echo '{"message":"Must specify two-factor authentication OTP code.","documentation_url":"https://developer.github.com/v3/auth#working-with-two-factor-authentication"}'
    ++ /usr/bin/jq -r '.resources | ( keys[] as $k | "\( $k ):\( .[$k].limit ):\( .[$k].remaining ):\( .[$k].reset )" )'
    jq: error (at <stdin>:1): null (null) has no keys
    + RATE_LIMIT_DATA_LINES=
    + test 5 -ne 0
    + printf 'ads-github-show-rate-limits (error): was unable to extract rate limit data from GitHub service response; bailing out\n'
    ads-github-show-rate-limits (error): was unable to extract rate limit data from GitHub service response; bailing out
    + exit 1
    + f_cleanup
    + test 0 -eq 0
    + return

    $ ads-github-show-rate-limits --version
    ads-github-show-rate-limits 0.2.0  (built: 2017-02-26 16:52:08)
    Copyright (C) 2016 Alan D. Salewski
    License GPLv2+: GNU GPL version 2 or later <http://gnu.org/licenses/gpl.html>.
    This is free software: you are free to change and redistribute it.
    There is NO WARRANTY, to the extent permitted by law.

    Written by Alan D. Salewski.

[salewski]

The issue has been fixed for 'ads-github-tools-0.3.1'

The blurb about it from our 'NEWS' file:

*** issue 44: ads-github-show-rate-limits: http response code not checked

    https://github.com/salewski/ads-github-tools/issues/44

    The 'ads-github-show-rate-limits' program is now careful to check not only
    the curl(1) exit status of the 'GET /rate_limit' request, but also the
    HTTP response status. Previously it was obtaining the JSON response on the
    curl(1) stdout, and had no way to determine what the HTTP response code
    was. The new behavior is to follow our pattern of saving the raw response
    output to a temporary file, and having curl write the HTTP response code
    to stdout; this allows us to deal with both aspects independently.

    When the 'GET /rate_limit' call results in a non-success status, the
    program now emits and error message and exits with a non-zero status, as
    one would expect. If a JSON response payload was returned, it will be
    printed beneath the error message to provide additional context for the
    failure.

    Ex. 1:
    :    ads-github-show-rate-limits (error): HTTP response code was: "401"; expected 200 ("OK"); bailing out
    :        HTTP response payload may contain additional info:
    :            {"message":"Bad credentials","documentation_url":"https://docs.github.com/rest"}

    Ex. 2:
    :    ads-github-show-rate-limits (error): HTTP response code was: "404"; expected 200 ("OK"); bailing out
    :        HTTP response payload may contain additional info:
    :            {"message":"Not Found","documentation_url":"https://docs.github.com/rest"}

    If no response payload was returned, that fact will be explicitly stated,
    as well:

    Ex. 3:
    :    ads-github-show-rate-limits (error): HTTP response code was: "500"; expected 200 ("OK"); bailing out
    :        (HTTP response payload was empty)