[Nmh-workers] sortm -check (was: sortm's Default of all is Brain-Damaged.)

[David Levine]

Norm wrote:

> While people are thinking about sortm, here are some thoughts.
>
> Generally, mh avoided doing anything if a command found anything
> wrong anywhere.  This is the extreme opposite to the de-facto UNIX
> standard, which is always to do whatever you can. There are some
> exceptions. In particular sortm will try to do its thing even if it
> encounters messages with no date field, or an unparseable date
> field. There are two good reasons for this, both most relevant to
> sorting lots of messages.
>
> First, having to check first would probably impact performance.
> Secondly, consider the plight of a user trying sort 15000 messages,
> who is told he can't sortm them until he deals with three bad
> messages.
>
> BUT, after sortm has done its thing, the errant message numbers it
> reports are no longer valid.
>
> This is what leads me to suggest two more options "-check" and
> "-nocheck", with -nocheck the default. With -check, sortm would do
> nothing if it encountered a problem.

Added.  It actually does something with -check:  it still
prints its warning for each such message.

I also removed this note under BUGS in the sortm man page:

   If sortm encounters a message without a date-field, or if
   the  message has  a date-field  that sortm  cannot parse,
   then  sortm attempts  to  keep the  message  in the  same
   relative  position.   This  does not  always  work.   For
   instance, if  the first message encountered  lacks a date
   which can  be parsed, then  it will usually be  placed at
   the end of the messages being sorted.

because it was incorrect.  Since March of 1990, the code has
used the file modification times in those cases.

Here's the man page addition for -check/-nocheck:

   sortm always  issues a warning  for each message  that is
   missing a "Date:" field, has  a "Date:" field that cannot
   be parsed,  or has  a format error  in any  header field.
   With the -check switch,  sortm inhibits all modifications
   to the folder if there  any such messages, and exits with
   non-zero  status.  With  the default  of -nocheck,  sortm
   sorts messages  with a  missing or invalid  "Date:" field
   using their file modification times.

David