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Re: new tar behavior and --wildcards (proposed middle ground)

Both sides in this discussion seem to have valid concerns:

 FOR making --wildcard the default

   - compatibility with upstream
   - compatibility with standards
   - compatibility with other distributions
   - whatever reasons POSIX had for this were probably sensible
   - upstream's judgement on this is likely to be correct

 AGAINST making --wildcard the default

   - very difficult to figure out what scrips are affected
   - mysterious breakage far into the future
   - requires grubbing around and inserting --wildcard in many places

As a compromise that addresses some of the issues I would suggest the
following: go with upstream, but add some convenience code, to whit:

(1) Hot-wire tar to check an environment variable TAR_WILDCARD_DEFAULT
    and activate the --wildcard option if set.

(2) Hot-wire tar to print a warning message to stderr if it
    (a) is defaulting to the --no-wildcard behaviour and,
    (b) it notices a filename that, had tar instead been
        in --wildcards mode, would have been expanded.
    If stderr is not hooked up, the warning could reasonably be sent
    using syslog() instead.  I wouldn't bother adding any mechanism
    to shut these warnings off; if one really wants them shut off,
    use either --wildcards or --no-wildcards.

Point (1) would allow people to easily check if some breakage is
caused by this change, or to use old scripts/sources without
contortions; and point (2) would serve to catch problems in scripts
that might otherwise elude us.  Point (2) would be especially helpful
given that we're coming up on a release, so it would be nice to find
and correct all affected scripts as rapidly as possible.
Barak A. Pearlmutter
 Hamilton Institute & Dept Comp Sci, NUI Maynooth, Co. Kildare, Ireland

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