depends_on cannot handle ^ sigil (#18220)

* depends_on cannot handle ^ sigil

* cardioid+mfem+cuda requires hypre+cuda

* Document this limitation

* Move warning message to Known Issues docs

* Better handling of parmetis dep

var/spack/repos/builtin/packages/cardioid/package.py

@@ -25,8 +25,8 @@ class Cardioid(CMakePackage):
     depends_on('lapack')
     depends_on('mpi')
     depends_on('cuda', when="+cuda")
-    depends_on('mfem+mpi+superlu-dist+lapack', when="+mfem~cuda")
-    depends_on('mfem+mpi+superlu-dist+lapack^hypre+cuda', when="+mfem+cuda")
+    depends_on('mfem+mpi+superlu-dist+lapack', when="+mfem")
+    depends_on('hypre+cuda', when="+mfem+cuda")
     depends_on('cmake@3.1:', type='build')
     depends_on('perl', type='build')
 

var/spack/repos/builtin/packages/parmetis/package.py

@@ -22,10 +22,13 @@ class Parmetis(CMakePackage):
 
     variant('shared', default=True, description='Enables the build of shared libraries.')
     variant('gdb', default=False, description='Enables gdb support.')
+    variant('int64', default=False, description='Sets the bit width of METIS\'s index type to 64.')
 
     depends_on('cmake@2.8:', type='build')
     depends_on('mpi')
     depends_on('metis@5:')
+    depends_on('metis+int64', when='+int64')
+    depends_on('metis~int64', when='~int64')
 
     patch('enable_external_metis.patch')
     # bug fixes from PETSc developers

var/spack/repos/builtin/packages/phist/package.py

@@ -118,8 +118,8 @@ class Phist(CMakePackage):
     depends_on('ghost', when='kernel_lib=ghost')
 
     depends_on('trilinos+anasazi+belos+teuchos', when='+trilinos')
-    depends_on('parmetis ^metis+int64', when='+parmetis +int64')
-    depends_on('parmetis ^metis~int64', when='+parmetis ~int64')
+    depends_on('parmetis+int64', when='+parmetis+int64')
+    depends_on('parmetis~int64', when='+parmetis~int64')
 
     # Fortran 2003 bindings were included in version 1.7, previously they
     # required a separate package

var/spack/repos/builtin/packages/warpx/package.py

@@ -51,7 +51,7 @@ class Warpx(MakefilePackage):
     depends_on('openpmd-api +mpi', when='+openpmd +mpi')
     depends_on('ascent', when='+ascent')
     depends_on('ascent +cuda', when='+ascent backend=cuda')
-    depends_on('ascent +mpi ^conduit~hdf5', when='+ascent +mpi')
+    depends_on('ascent +mpi', when='+ascent +mpi')
 
     resource(name='amrex',
              git='https://github.com/AMReX-Codes/amrex.git',