## Context ##

* Python is executing a script on behalf of a web server (e.g. Apache httpd) following the CGI protocol.
* cgitb is enabled and configured to use the 'text' format.
* An unhandled exception occurs before any CGI response headers have been emitted.


## Expected behaviour ##

A valid response is returned from the CGI script to the web server and ultimately to the client.


## Observed behaviour ##

The response is rejected by the web server because it does not begin with a valid CGI header block.

    [cgi:error] [pid xxxxx] [client xxx.xxx.xxx.xxx:xxxxx] malformed header from script 'web.py': Bad header: <p>A problem occurred in a Pyt

Any traceback info included (if display=1) gets discarded and the web server returns its own Internal Server Error response instead.


## Comments ##

A valid response is observed if format='html'. This bug only concerns format='text'.
The behaviour is the same regardless of whether display=0 or display=1.

I imagine this is because cgitb.reset (which emits the headers) is only called when format='html'.
We could resolve this by always calling cgitb.reset regardless of the format, or by introducing separate text-format and HTML-format versions of cgitb.reset.
I'm happy to prepare a patch if you agree on the approach.

I would think the use case for 'text' is to not print the output to a web page, so you wouldn't want the headers. The documentation says that cgitb was generalized to not only produce output for web pages. The 'text' format provides this generalization.

Changing to an enhancement request for 3.11. We can't change the 'text' format because it would break existing code. so this is really an enhancement request for a new format. But I don't see what the use case would be, so I don't think it would be accepted.

What's the case where you need this functionality? How is the 'html' format unacceptable?

Having not heard back about a use case for this, I'm going to close it. If you want to move this forward, I suggest proposing it on the python-ideas mailing list.