Why is afw recompiling when nothing appears to have changed?

I just ran rebuild ci_hsc and then perhaps 15 minutes later rebuild validation_data_hsc.

Why did the second invocation trigger a rebuild of afw (2.2016.10-8-g2cef314+2), whose last commit to master was March 31?

The rebuild ci_hsc did not trigger a rebuild of afw.

[serenity ~] rebuild validation_data_hsc
 validation_data_hsc:  ok (2470.3 sec).
          obs_subaru:  ok (0.3 sec).
     daf_persistence:  ok (0.3 sec).
       mariadbclient:  ok (0.2 sec).
         pex_logging:  ok (0.3 sec).
      pex_exceptions:  ok (0.3 sec).
                base:  ok (0.3 sec).
               boost:  ok (0.2 sec).
              python:  ok (0.2 sec).
          sconsUtils:  ok (0.3 sec).
               scons:  ok (0.2 sec).
             doxygen:  ok (0.2 sec).
                swig:  ok (0.2 sec).
            daf_base:  ok (0.3 sec).
               utils:  ok (0.3 sec).
               numpy:  ok (0.2 sec).
          pex_policy:  ok (0.3 sec).
              pyfits:  ok (0.2 sec).
        python_d2to1:  ok (0.2 sec).
     stsci_distutils:  ok (0.2 sec).
              pyyaml:  ok (0.3 sec).
     daf_butlerUtils:  ok (0.3 sec).
                 afw:  ok (0.5 sec).
          pex_config:  ok (0.4 sec).
             ndarray:  ok (0.5 sec).
               eigen:  ok (0.5 sec).
                fftw:  ok (0.7 sec).
             cfitsio:  ok (0.7 sec).
              wcslib:  ok (0.7 sec).
             minuit2:  ok (0.6 sec).
                 gsl:  ok (0.4 sec).
          matplotlib:  ok (0.4 sec).
             afwdata:  ok (0.3 sec).
              skypix:  ok (0.3 sec).
                geom:  ok (0.2 sec).
          pipe_tasks:  ok (0.3 sec).
           pipe_base:  ok (0.3 sec).
            obs_test:  ok (0.3 sec).
              esutil:  ok (0.2 sec).
           meas_base:  ok (0.4 sec).
         coadd_utils:  ok (0.3 sec).
     meas_algorithms:  ok (0.3 sec).
         meas_astrom:  ok (0.3 sec).
      astrometry_net:  ok (0.2 sec).
      meas_deblender:  ok (0.4 sec).
 astrometry_net_data:  ok (0.3 sec).
              ip_isr:  ok (0.4 sec).
           ip_diffim:  ok (0.3 sec).
    coadd_chisquared:  ok (0.3 sec).
              skymap:  ok (0.3 sec).
       meas_modelfit:  ok (0.3 sec).
            shapelet:  ok (0.3 sec).
meas_extensions_psfex:  ok (0.3 sec).
               psfex:  ok (0.3 sec).
     testdata_subaru:  ok (0.2 sec).
# BUILD ID: b1973
             cfitsio: 3360.lsst4 (already installed).
             minuit2: 5.28.00.lsst2-1-gdae2fb7 (already installed).
               eigen: 3.2.5-1-g70497dd (already installed).
              python: 0.0.3 (already installed).
                swig: 3.0.2.lsst1 (already installed).
       mariadbclient: 10.1.11.lsst2 (already installed).
              pyyaml: 3.11.lsst1 (already installed).
             doxygen: 1.8.5.lsst1 (already installed).
              wcslib: 5.13.lsst1 (already installed).
               boost: 1.59.lsst5 (already installed).
                fftw: 3.3.4.lsst2 (already installed).
               scons: 2.3.5 (already installed).
     testdata_subaru: master-gf9ba9abdbe (already installed).
        python_d2to1: 0.2.12.lsst1 (already installed).
          sconsUtils: 2016_01.0-4-g49bc714 (already installed).
               numpy: 0.0.2 (already installed).
                 gsl: 1.16.lsst3 (already installed).
      astrometry_net: 0.50.lsst2+6 (already installed).
          matplotlib: 0.0.2 (already installed).
                base: 2.2016.10+2 (already installed).
             afwdata: 2.2016.10+2 (already installed).
      pex_exceptions: 2016_01.0+6 (already installed).
             ndarray: 2016_01.0-1-g4d828c7 ok (31.4 sec).
               psfex: 2016_01.0+4 (already installed).
              esutil: 0.5.3 (already installed).
     stsci_distutils: 0.3.7-1-gb22a065+1 (already installed).
                geom: (already installed).
 astrometry_net_data: (already installed).
               utils: 2016_01.0+7 (already installed).
              pyfits: 3.4.0+2 (already installed).
            daf_base: 2016_01.0+7 (already installed).
          pex_policy: 2016_01.0+7 (already installed).
         pex_logging: 2016_01.0-1-g90faa74+3 (already installed).
          pex_config: 2016_01.0+7 (already installed).
     daf_persistence: 2016_01.0-8-geb625e2 (already installed).
                 afw: 2.2016.10-8-g2cef314+2 ............................................................................................................

Because a dependency was rebuilt.

Ah, thank you. Missed that one.

Ah, this was the ndarray bug that @jbosch fixed indeed just today.