qt: Assimp dependency specificationa is more nuanced (#30460)

libassimp has been a dependency for all of 5.x but expressing that has
varied significantly throughout the 5.x lifecycle:

  v5.0:  qt3d uses internal-only libassimp
  v5.5:  external-only libassimp
  v5.6:  either internal or external libassimp via autodetection
  v5.9:  user-selectable internal-vs-external via -assimp
  v5.14: additional qtquick3d module uses -assimp
  v5.15: qtquick3d switches to the -quick3d-assimp option
    * current bug where the incorrect target is setup

2 files changed, 29 insertions, 18 deletions

diff --git a/var/spack/repos/builtin/packages/qt/package.py b/var/spack/repos/builtin/packages/qt/package.py
index 8bc9e920af..467413a82b 100644
--- a/var/spack/repos/builtin/packages/qt/package.py
+++ b/var/spack/repos/builtin/packages/qt/package.py
@@ -134,7 +134,7 @@ class Qt(Package):
     patch('qt514.patch', when='@5.14')
     patch('qt514-isystem.patch', when='@5.14.2')
     # https://bugreports.qt.io/browse/QTBUG-84037
-    patch('qt514-quick3d-assimp.patch', when='@5.14:5')
+    patch('qt515-quick3d-assimp.patch', when='@5.15:5')
     # https://bugreports.qt.io/browse/QTBUG-90395
     patch('https://src.fedoraproject.org/rpms/qt5-qtbase/raw/6ae41be8260f0f5403367eb01f7cd8319779674a/f/qt5-qtbase-gcc11.patch',
           sha256='9378afd071ad5c0ec8f7aef48421e4b9fab02f24c856bee9c0951143941913c5',
@@ -183,7 +183,7 @@ class Qt(Package):
     depends_on("libpng", when='@4:')
     depends_on("dbus", when='@4:+dbus')
     depends_on("gl", when='@4:+opengl')
-    depends_on("assimp@5.0.0:5", when='@5.14:+opengl')
+    depends_on("assimp@5.0.0:5", when='@5.5:+opengl')
 
     depends_on("harfbuzz", when='@5:')
     depends_on("double-conversion", when='@5.7:')
@@ -510,6 +510,13 @@ class Qt(Package):
             with open(conf_file, 'a') as f:
                 f.write("QMAKE_CXXFLAGS += -std=gnu++98\n")
 
+    def _use_spack_dep(spec, config_args, spack_pkg, qt_name=None):
+        pkg = spec[spack_pkg]
+        config_args.append('-system-' + (qt_name or spack_pkg))
+        if not pkg.external:
+            config_args.extend(pkg.libs.search_flags.split())
+            config_args.extend(pkg.headers.include_flags.split())
+
     @property
     def common_config_args(self):
         spec = self.spec
@@ -527,12 +534,8 @@ class Qt(Package):
             '-no-pch',
         ]
 
-        def use_spack_dep(spack_pkg, qt_name=None):
-            pkg = spec[spack_pkg]
-            config_args.append('-system-' + (qt_name or spack_pkg))
-            if not pkg.external:
-                config_args.extend(pkg.libs.search_flags.split())
-                config_args.extend(pkg.headers.include_flags.split())
+        use_spack_dep = lambda spack_pkg, qt_name=None: _use_spack_dep(
+            spec, config_args, spack_pkg, qt_name)
 
         if '+gui' in spec:
             use_spack_dep('freetype')
@@ -585,12 +588,6 @@ class Qt(Package):
                 '-no-nis',
             ])
 
-        if '+opengl' in spec:
-            if version >= Version('5.14'):
-                use_spack_dep('assimp')
-            else:
-                config_args.append('-no-assimp')
-
         # COMPONENTS
 
         if '~examples' in spec:
@@ -677,6 +674,9 @@ class Qt(Package):
                 '' if version >= Version('5.7') else 'style')
         ])
 
+        use_spack_dep = lambda spack_pkg, qt_name=None: _use_spack_dep(
+            spec, config_args, spack_pkg, qt_name)
+
         if MACOS_VERSION:
             if version < Version('5.9'):
                 config_args.append('-no-xcb-xlib')
@@ -724,17 +724,28 @@ class Qt(Package):
 
         if '~opengl' in spec:
             config_args.extend(['-skip', 'multimedia'])
+            config_args.extend(['-skip', 'qt3d'])
+
             if version >= Version('5.10'):
-                config_args.extend([
-                    '-skip', 'webglplugin',
-                    '-skip', 'qt3d',
-                ])
+                config_args.extend(['-skip', 'webglplugin'])
 
             if version >= Version('5.14'):
                 config_args.extend(['-skip', 'qtquick3d'])
 
             if version >= Version('5.15'):
                 config_args.extend(['-skip', 'qtlocation'])
+
+            # v5.0: qt3d uses internal-only libassimp
+            # v5.5: external-only libassimp
+            # v5.6: either internal or external libassimp via autodetection
+            # v5.9: user-selectable internal-vs-external via -assimp
+            # v5.14: additional qtquick3d module uses -assimp
+            # v5.15: qtquick3d switched to the -quick3d-assimp option
+            if version >= Version('5.9'):
+                use_spack_dep('assimp')
+            if version >= Version('5.15'):
+                use_spack_dep('assimp', 'quick3d-assimp')
+
         elif MACOS_VERSION:
             # These options are only valid if 'multimedia' is enabled, i.e.
             # +opengl is selected. Force them to be off on macOS, but let other
diff --git a/var/spack/repos/builtin/packages/qt/qt514-quick3d-assimp.patch b/var/spack/repos/builtin/packages/qt/qt515-quick3d-assimp.patch
index 68f4e14c60..68f4e14c60 100644
--- a/var/spack/repos/builtin/packages/qt/qt514-quick3d-assimp.patch
+++ b/var/spack/repos/builtin/packages/qt/qt515-quick3d-assimp.patch