random header generation failures (maybe when parallel building?)

[jku]

Sometimes the header generation seems to fail. I've seen these issues pop up randomly mostly when using icecc (distributed build system) but have reproduced on a single machine as well.

A Full log of failing compile is in gist but the failure looks like this:

| In file included from /home/jku/src/poky/build/tmp/work/core2-64-poky-linux/libical/1.0.1-r0/libical-1.0.1/src/libicalvcal/icalvcal.h:29:0,
|                  from /home/jku/src/poky/build/tmp/work/core2-64-poky-linux/libical/1.0.1-r0/libical-1.0.1/src/libicalvcal/icalvcal.c:46:
| /home/jku/src/poky/build/tmp/work/core2-64-poky-linux/libical/1.0.1-r0/build/src/libical/ical.h:1019:1: error: unknown type name 'icalvalue'
| /home/jku/src/poky/build/tmp/work/core2-64-poky-linux/libical/1.0.1-r0/build/src/libical/ical.h:1019:26: error: unknown type name 'icalvalue_kind'
| /home/jku/src/poky/build/tmp/work/core2-64-poky-linux/libical/1.0.1-r0/build/src/libical/ical.h:1021:1: error: unknown type name 'icalvalue'
| /home/jku/src/poky/build/tmp/work/core2-64-poky-linux/libical/1.0.1-r0/build/src/libical/ical.h:1021:38: error: unknown type name 'icalvalue'
| /home/jku/src/poky/build/tmp/work/core2-64-poky-linux/libical/1.0.1-r0/build/src/libical/ical.h:1023:1: error: unknown type name 'icalvalue'
| /home/jku/src/poky/build/tmp/work/core2-64-poky-linux/libical/1.0.1-r0/build/src/libical/ical.h:1023:38: error: unknown type name 'icalvalue_kind'
| /home/jku/src/poky/build/tmp/work/core2-64-poky-linux/libical/1.0.1-r0/build/src/libical/ical.h:1025:21: error: unknown type name 'icalvalue'
| /home/jku/src/poky/build/tmp/work/core2-64-poky-linux/libical/1.0.1-r0/build/src/libical/ical.h:1027:30: error: unknown type name 'icalvalue'
| /home/jku/src/poky/build/tmp/work/core2-64-poky-linux/libical/1.0.1-r0/build/src/libical/ical.h:1029:44: error: unknown type name 'icalvalue'
| /home/jku/src/poky/build/tmp/work/core2-64-poky-linux/libical/1.0.1-r0/build/src/libical/ical.h:1030:40: error: unknown type name 'icalvalue'
| /home/jku/src/poky/build/tmp/work/core2-64-poky-linux/libical/1.0.1-r0/build/src/libical/ical.h:1032:1: error: unknown type name 'icalvalue_kind'
    (and so on for a long time)

When this failure happens ical.h really is missing parts that should be there -- lines from icalderivedproperty.h.in, icalderivedparameter.h.in and icalderivedvalue.h.in are missing: the individual headers themselves (like icalderivedvalue.h) look correct but maybe they weren't when ical.h was generated? If I re-run make without changes, ical.h gets properly generated -- this seems to agree with the theory.

I've looked in your CMakeLists.txt and I can't see anything wrong with the dependencies though...

[jku]

A different failure but probably the same root cause:

| In file included from /home/jku/src/poky/build/tmp/work/core2-64-poky-linux/libical/1.0.1-r0/libical-1.0.1/src/libicalss/icalclassify.c:30:0:
| /home/jku/src/poky/build/tmp/work/core2-64-poky-linux/libical/1.0.1-r0/build/src/libical/ical.h:1:0: error: unterminated #ifndef
|  #ifndef LIBICAL_ICAL_H
|  ^

Looks like this time ical.h itself wasn't fully written by the time compilation starts. I checked ical.h afterwards and the #endif is there.

[winterz]

I recently fixed parallel builds in master branch.

[jku]

Thanks! This line (and others like it for the executables) from your recent commit does indeed help with 1.0.1:

add_dependencies(ical-static ical-header)