commit 5df4d7dfd8d77dd16aa3a0b398d50a22f4c85daa
author Jeff Genovy <29107334+jefgen@users.noreply.github.com> Wed Apr 24 14:02:06 2019 -0700
committer Jeff Genovy <29107334+jefgen@users.noreply.github.com> Thu Apr 25 15:39:20 2019 -0700
tree 13ca6b96de925356e8858978594f90f5e5d8ba69
parent 4f715ae124c418a15a3fa4d8fb14f406576a7ee5

ICU-20558 Fix regression in DateTimePatternGenerator (Backport for 63)

Backporting to ICU 63. This is manually cherry-picked from
commit: 693adf3987c192c9ec649bc88e3e41b52f23204d

This fixes a regression introduced by commit
b12a927c9365bb38831afbf76fdd0999f8f33deb for issue ICU-13778.

The above commit improved the error checking in the
DateTimePatternGenerator class, adding checks for errors/failures
where there previously was none at all. This was done in order to
catch catastrophic errors like out-of-memory (OOM), and properly
report them to the caller, rather than ignoring/hiding these errors.

However, in doing so it exposed a case where the code was depending
on ignoring errors in order to fall-back to the Gregorian calendar
when the default ICU locale is set to root.

This restores the previous behavior, by allowing the error of
U_MISSING_RESOURCE_ERROR to fall-though and continue without
reporting back an error to the caller.

Note: This regression was technically introduced in ICU 63, and
also effects ICU 64 as well.