Re: pg_ls_tmpdir to show directories and shared filesets (and pg_ls_*)

In an attempt to get this patch set off the ground again, I took a
look at the first 5 patches.

0001: This one is a very small documentation update for pg_stat_file
to point out that isdir will be true for symbolic links to
directories. Given this is true, I think the patch looks good.

0002: This patch adds some very basic testing for pg_ls_dir(). The
only comment that I have for this one is that I might also check
whether '..' is included in the results of the include_dot_dirs tests.
The docs specifically note that include_dot_dirs indicates whether
both '.' and '..' are included, so IMO we might as well verify that.

0003: This one didn't apply cleanly until I used 'git apply -3', so it
likely needs a rebase. This patch introduces the pg_ls_dir_metadata()
function, which appears to just be pg_ls_dir() with some additional
columns for the size and modification time. My initial reaction to
this one is that we should just add those columns to pg_ls_dir() to
match all the other pg_ls_* functions (and not bother attempting to
maintain historic behavior for things like hidden and special files).
I believe there is some existing discussion on this point upthread, so
perhaps there is a good reason to make a new function. In any case, I
like the idea of having pg_ls_dir() use pg_ls_dir_files() internally
like the rest of the pg_ls_* functions.

0004: This one changes pg_ls_tmpdir to show directories as well. I
think this is a reasonable change. On it's own, the patch looks
alright, although it might look different if my suggestions for 0003
were followed.

0005: This one adjusts the rest of the pg_ls_* functions to show
directories. Again, I think this is a reasonable change. As noted in
0003, I think it'd be alright just to have all the pg_ls_* functions
show special and hidden files as well. It's simple enough already to
filter our files that start with '.' if necessary, and I'm not sure
there's any strong reason for leaving out special files. If special
files are included, perhaps isdir should be changed to indicate the
file type instead of just whether it is a directory. (Reading ahead,
it looks like this is what 0009 might do.)

I haven't looked at the following patches too much, but I'm getting
the idea that they might address a lot of the feedback above and that
the first bunch of patches are more like staging patches that add the
abilities without changing the behavior. I wonder if just going
straight to the end goal behavior might simplify the patch set a bit.
I can't say I feel too strongly about this, but I figure I'd at least
share my thoughts.

Nathan