Issue 214754: marshal_loads can return NULL without setting Error

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src="@@file/gh-icon.png" /> <p> <span>This issue has been migrated to GitHub:</span> https://github.com/python/cpython/issues/33142 </p> </a> </div> <fieldset><legend>classification</legend> <table class="form"> <tr> <th class="required"><a href="http://docs.python.org/devguide/triaging.html#title" target="_blank">Title</a>:</th> <td colspan="3"> <span>marshal_loads can return NULL without setting Error</span> <input type="hidden" name="title" value="marshal_loads can return NULL without setting Error"> </td> </tr> <tr> <th class="required"><a href="http://docs.python.org/devguide/triaging.html#type" target="_blank">Type</a>:</th> <td>enhancement</td> <th><a href="http://docs.python.org/devguide/triaging.html#stage" target="_blank">Stage</a>:</th> <td></td> </tr> <tr> <th><a href="http://docs.python.org/devguide/triaging.html#components" target="_blank">Components</a>:</th> <td>Interpreter Core</td> <th><a href="http://docs.python.org/devguide/triaging.html#versions" target="_blank">Versions</a>:</th> <td></td> </tr> </table> </fieldset> <fieldset><legend>process</legend> <table class="form"> <tr> <th><a href="http://docs.python.org/devguide/triaging.html#status" target="_blank">Status</a>:</th> <td>closed</td> <th><a href="http://docs.python.org/devguide/triaging.html#resolution" target="_blank">Resolution</a>:</th> <td>later</td> </tr> <tr> <th> <a href="http://docs.python.org/devguide/triaging.html#dependencies" target="_blank">Dependencies</a>: </th> <td> </td> <th><a href="http://docs.python.org/devguide/triaging.html#superseder" target="_blank">Superseder</a>:</th> <td> </td> </tr> <tr> <th> <a href="http://docs.python.org/devguide/triaging.html#assigned-to" target="_blank">Assigned To</a>: </th> <td> gvanrossum </td> <th> <a href="http://docs.python.org/devguide/triaging.html#nosy-list" target="_blank">Nosy List</a>: </th> <td> gvanrossum, skip.montanaro </td> </tr> <tr> <th> <a href="http://docs.python.org/devguide/triaging.html#priority" target="_blank">Priority</a>: </th> <td>high</td> <th> <a href="http://docs.python.org/devguide/triaging.html#keywords" target="_blank">Keywords</a>: </th> <td></td> </tr> </table> </fieldset> </form> <p>Created on <strong>2000-09-18 22:46</strong> by <strong>skip.montanaro</strong>, last changed <strong>2022-04-10 16:02</strong> by <strong>admin</strong>. This issue is now <strong style="color:#00F; background-color:inherit;">closed</strong>.</p> <table class="messages"> <tr><th colspan="4" class="header">Messages (2)</th></tr> <tr> <th> <a href="#msg1438" id="msg1438">msg1438</a> - <a href="msg1438">(view)</a></th> <th>Author: Skip Montanaro (skip.montanaro) <span title="Contributor form received">*</span> <img src="@@file/triager.png" title="Python triager" alt="(Python triager)" /></th> <th>Date: 2000-09-18 22:46</th> </tr> <tr> <td colspan="4" class="content"> <pre>I'm getting a NULL result from marshal_loads without it setting an error. (This is in 1.5.2 and 2.0b1.) I'm pretty sure the input being fed to marshal.loads is bad, but it still should still doing the error handling dance correctly, yes? Here's a simple example: >>> import marshal >>> x = marshal.loads('<a href="mailto:006@mediaone.net.weekly.529454">006@mediaone.net.weekly.529454</a>') Traceback (most recent call last): File "<stdin>", line 1, in ? SystemError: NULL result without error in call_object It looks like r_object returns NULL if type == '0' and then marshal_loads simply returns it without checking the value returned by r_object. If this is a "feature" and not a bug, there should at least be a comment in the TYPE_NULL branch of the switch statement indicating why it's not an error to return NULL without setting an exception. (P.S. Is there any search facility within the SF bug manager or are you stuck having to wade through all bugs to find out if yours has already been reported?) </pre> </td> </tr> <tr> <th> <a href="#msg1439" id="msg1439">msg1439</a> - <a href="msg1439">(view)</a></th> <th>Author: Guido van Rossum (gvanrossum) <span title="Contributor form received">*</span> <img src="@@file/committer.png" title="Python committer" alt="(Python committer)" /></th> <th>Date: 2000-09-19 01:30</th> </tr> <tr> <td colspan="4" class="content"> <pre>Marshal is not very careful in validating its input -- it was written for speedy reading of .pyc files only. I agree that this should be fixed. Since a spurious '0' input character probably isn't the only bad input that it might choke on (it could even dump core!) I'm not going to fix this, but I'll add a feature request to <a href="https://www.python.org/dev/peps/pep-0042/">PEP 42</a>: better checking for bad input to marshal.load*().</pre> </td> </tr> </table> <table class="history table table-condensed table-striped"><tr><th colspan="4" class="header"> History </th></tr><tr> <th>Date</th> <th>User</th> <th>Action</th> <th>Args</th> </tr> <tr><td>2022-04-10 16:02:24</td><td>admin</td><td>set</td><td>github: 33142</td></tr> <tr><td>2000-09-18 22:46:37</td><td>skip.montanaro</td><td>create</td><td></td></tr> </table> </div> </div>  <div id="footer"> <div id="credits"> Supported by <a href="https://python.org/psf-landing/" title="The Python Software Foundation">The Python Software Foundation</a>, <br> Powered by <a href="http://roundup.sourceforge.net" title="Powered by the Roundup Issue Tracker">Roundup</a> </div>  Copyright © 1990-2022, <a href="http://python.org/psf">Python Software Foundation</a><br /> <a href="http://python.org/about/legal">Legal Statements</a> </div>  </div>  </div>  </body> </html>

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Issue 214754: marshal_loads can return NULL without setting Error - Python tracker