mshow: rendering a message numbers mime parts inconsistently with list mode

[ashiire]

When mshow renders a message, the numbering of structure markers differs from that shown by its list mode. This becomes a problem when browsing messages (i.e. using mless) and wanting to extract a specific attachment.

The discrepancy seems to arise from parts not rendered due to multipart/alternative preferences, as they are neither mentioned in the structure markers, nor counted. Perhaps they should be both mentioned and counted but not rendered?

Structure as rendered:

--- 1: multipart/related size=27924 ---
--- --- 2: multipart/alternative size=11924 ---
--- --- --- 3: text/plain size=885 ---

[...]

--- --- 4: image/jpeg size=11547 name="image001.jpg" ---

Structure as listed:

  1: multipart/related size=27924
    2: multipart/alternative size=11924
      3: text/plain size=885
      4: text/html size=9819
    5: image/jpeg size=11547 name="image001.jpg"

[leahneukirchen]

This has been reported by Ruda before, the problem is that we need to run filters to make this work...