Re: [PATCH v2 4/5] bitmap: add trace2 outputs during open "bitmap" file

[Teng Long <dyroneteng@gmail.com>]

> This might just be a style thing, but rather than logging the pathname
> in a separate data_string message, you can use the _printf version of
> region_enter and region_leave to also print the name of the
> path -- like I did in read-cache.c for the "do_read_index"
> calls.
> 
> ... | region_enter | ... | index | label:do_read_index .git/index
> ...
> ... | region_leave | ... | index | label:do_read_index .git/index

Appreciate for the input about the _printf version, we can choose to
let the region_enter and region_leave to print the pathname by moving
the related "midx_bitmap_filename()" and "pack_bitmap_filename" at
front, but it's not enough because both midx and normal bitmap support
multiple opening, so it's likely we keep on the current way using
"trace2_data_string()" in "open_pack_bitmap_1()" and "open_midx_bitmap_1()"
is a simpler solution.

I'm not sure If I totally get the meaning about your suggestion,
so correct me if I understand you wrong.

> As AEvar suggests in another message in this thread, I'm not sure if
> you need the region timing here for reading the bitmap, but all of
> the error and any other data messages will be bounded between the
> region_enter and region_leave events and that might (or might not)
> be helpful.

I think it's needed in my opinion, the bounded between the region is
helpful, especially when we want to know the detailed debug info like
we do in "open_midx_bitmap_1()".  


> Also, I agree with AEvar's statements about using error() and getting
> the trace2 error messages for free and not needing some of the
> trace2_data_string() messages that you have later in this file.
> 
> I wonder if it would be worth adding the pathname of the invalid
> file to those new error messages.  Granted you'll have it in the
> trace2 log, but then you'll also get it on stderr if that would
> be helpful.

I think I will remove the redundant "trace2_data_string()" code when
it will return by "error()".


Thanks.