my_timegm was introduced in 1900c7 to add a mktime fallback used in
4a6241, the subsequently removed in c53823. As a result of this code
shuffling, the jq mktime function (f_mktime) wound up using a fallback
even on systems where timegm is available, with incorrect results in
some time zones with DST, e.g.
% TZ=America/New_York jq -n '"2018-08-31T00:00:00Z"|fromdate|todate'
"2018-08-31T01:00:00Z"
This undoes 1900c7 and moves the workaround it added into the #else of
my_mktime.
This has been a complicated issue to fix for a number of reasons.
The core of it is that the behavior is different between different
versions of macOS, some of which set possible-but-incorrect values.
This commit addresses the issue by always using our computation for
tm_wday and tm_yday on macOS. As a side-effect, strptime format
strings that specify %u and %j will no longer work on macOS.
strptime() on OS X and *BSDs (reputedly) does not set tm_wday and
tm_yday unless corresponding %U and %j format specifiers were used.
That can be... surprising when one parsed year, month, and day anyways.
Glibc's strptime() conveniently sets tm_wday and tm_yday in those cases,
but OS X's does not, ignoring them completely.
This commit makes jq compute those where possible, though the day of
week computation may be wrong for dates before 1900-03-01 or after
2099-12-31.
OS X (and *BSD) strptime() does not set tm_wday nor tm_yday unless
corresponding format options are used. That means we must call timegm()
to set them.
It needs to be possible to do something like
getpath($paths[]) += 1
meaning: increment all the paths in . that are listed in $paths[].
In order to do this getpath() needs to update the jq->path and
jq->value_at_path as necessary.
Configure should still allow use of prebuilt onigurumas (whether
system-installed or in a special prefix). If these are not found, and
configure was not called with `--without-oniguruma`, then use the vendored
oniguruma module. If configure was called with `--without-oniguruma`, then we
do not build regex functionality into jq.
strptime() is an XPG4v2 function, on OpenBSD the prototype
is not included in time.h unless visibility is set, it needs
either "#define _XOPEN_SOURCE_EXTENDED 1" or _XOPEN_SOURCE
>= 500. Without this the prototype isn't included and
strptime's returned pointer is truncated to an int, causing
SEGV on 64-bit arches when using it.
Thanks @sthen
Derrick Pallas