[Bug 47809] New: mscrt: strftime is missing some substutions

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=47809

Bug ID: 47809
           Summary: mscrt: strftime is missing some substutions
           Product: Wine
           Version: unspecified
          Hardware: x86
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: msvcrt
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

I realize that I am using a non-standard config to report this bug, but please
read it all the way through.

I first realized this issue when installing a few Lua addons into Elder Scrolls
Online (run via Proton because that's the only way I can get it work).

In the process I found that a couple of addons I had added were crashing. After
verifying that the issue does not appear in Windows under the same
circumstances I opted to have a look.

After a little digging I found that these crashes were due to addon calls to
Lua os.date. I dug through the Lua code and found that os.date calls strftime
for its results.

The addons that were giving me issues were LibDateTime and LibDebugLogger,
which begin their failure due to the following calls:

LibDateTime: os.date("%V", timestamp)
LibDebugLogger: os.date("%F %T.%%03.0f %z", timestamp / 1000)

After looking at the code in msvcrt (linked to by crtdll) I can see that there
is no implementation of the %V token (which gives the first error). I did fix
the second error by using the 3-token substitutions of %F and %T, but I had to
substitute both (%F simply isn't implemented, but even expanding %F and leaving
%T -- which is implemented -- didn't work either) to get it working.

Cross-referencing the Microsoft docs about the substitutions, I ran across the
following missing substitutions:

%C - Century, year dividied by 100 and truncated to integer
%D - Same as %m/%d/%y
%e - Day of month as decimal, with leaded space if requried
%F - Same as %Y-%m-%d
%g - Two-digit ISO 8601 week-based year
%G - ISO 8601 week-based year
%h - Same as %b
%n - newline character
%R - Same as %H:%M
%r - Locale's 12-hour clock time
%t - horizontal tab
%u - ISO 8601 week day
%V - ISO 8601 week number

I'm not sure if %T is working correctly, so I'll have to find some way to test
that.

Reference:
https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/strftime-wc...