Re: emacs-25 b6b47AF: Properly encode/decode base64Binary data in SOAP

[Eli Zaretskii <eliz@gnu.org>]

> From: Thomas Fitzsimmons <fitzsim@fitzsim.org>
> Cc: monnier@iro.umontreal.ca,  emacs-devel@gnu.org
> Date: Sun, 13 Mar 2016 13:57:32 -0400
> 
>    (defun soap-parse-server-response ()
>      "Error-check and parse the XML contents of the current buffer."
>      (let ((mime-part (mm-dissect-buffer t t)))
>        (unless mime-part
>          (error "Failed to decode response from server"))
>        (unless (equal (car (mm-handle-type mime-part)) "text/xml")
>          (error "Server response is not an XML document"))
>        (with-temp-buffer
>          (mm-insert-part mime-part)
>          (prog1
>              (car (xml-parse-region (point-min) (point-max)))
>            (kill-buffer)
>            (mm-destroy-part mime-part)))))
> 
> mm-insert-part does:
> 
>    (string-to-multibyte (mm-get-part handle no-cache))

Why does it do that?  string-to-multibyte is one of those functions
that should never be used.

> In cases where the caller is expecting an xsd:string, the idea is for
> soap-client to return a native Emacs string, for the caller's
> convenience.

But that's not what string-to-multibyte does.

> I guess soap-client assumes that the mm and xml packages will do the
> right thing to convert XML string values into Emacs's internal
> format.

I'm not sure we are not mis-communicating: conversion into internal
format is what decoding does.  Whereas you just said a few messages
upthread that you thought strings should be returned undecoded,
i.e. as binary streams of bytes.  What am I missing?

> >> Is the attached patch OK for master and emacs-25?
> >
> > Doesn't it bring back the bug which caused Andreas to make the change
> > you want to undo?
> 
> It brings back the behavior of soap-client returning base64-decoded
> xsd:base64Binary values as unibyte strings.

I'm confused: you've just demonstrated that it returns them as
multibyte strings with raw bytes in their multibyte encoding.

> The debate on this thread is about whether that behavior is buggy or
> not.  But yes, I want to revert Andreas's change on both master and
> emacs-25 branches, because I don't consider the old behavior buggy.

That'll bring the bug in the debbugs package back, I think.  Once
again, if you want to return undecoded strings, they should at the
very least be unibyte, not multibyte.  Apologies if I'm too confused
to talk intelligently about this.