MesonPackage: make "default_library" a multi-valued variant (#23540)

Currently if one package does `depends_on('pkg default_library=shared')`
and another does `depends_on('pkg default_library=both')`, you'd get a
concretization error.

With this PR one package can do `depends_on('pkg default_library=shared')` 
and another depends_on('default_library=static'), and it would concretize to 
`pkg default_library=shared,static`

Co-authored-by: Massimiliano Culpo <massimiliano.culpo@gmail.com>

2 files changed, 11 insertions, 12 deletions

diff --git a/lib/spack/spack/build_systems/meson.py b/lib/spack/spack/build_systems/meson.py
index 8f9972ba2e..14fe093f28 100644
--- a/lib/spack/spack/build_systems/meson.py
+++ b/lib/spack/spack/build_systems/meson.py
@@ -55,9 +55,8 @@ class MesonPackage(PackageBase):
     variant('buildtype', default='debugoptimized',
             description='Meson build type',
             values=('plain', 'debug', 'debugoptimized', 'release', 'minsize'))
-    variant('default_library', default='shared',
-            description=' Default library type',
-            values=('shared', 'static', 'both'))
+    variant('default_library', default='shared', values=('shared', 'static'),
+            multi=True, description='Build shared libs, static libs or both')
     variant('strip', default=False, description='Strip targets on install')
 
     depends_on('meson', type='build')
@@ -102,9 +101,11 @@ class MesonPackage(PackageBase):
 
         strip = 'true' if '+strip' in pkg.spec else 'false'
 
-        try:
-            default_library = pkg.spec.variants['default_library'].value
-        except KeyError:
+        if 'libs=static,shared' in pkg.spec:
+            default_library = 'both'
+        elif 'libs=static' in pkg.spec:
+            default_library = 'static'
+        else:
             default_library = 'shared'
 
         args = [
diff --git a/var/spack/repos/builtin/packages/libfuse/package.py b/var/spack/repos/builtin/packages/libfuse/package.py
index 8df03c5366..298c0decdf 100644
--- a/var/spack/repos/builtin/packages/libfuse/package.py
+++ b/var/spack/repos/builtin/packages/libfuse/package.py
@@ -68,12 +68,10 @@ class Libfuse(MesonPackage):
             "INIT_D_PATH={0}".format(self.prefix.etc),
         ]
 
-        if 'default_library=shared' in self.spec:
-            args.extend(['--enable-shared', '--disable-static'])
-        elif 'default_library=static' in self.spec:
-            args.extend(['--disable-shared', '--enable-static'])
-        else:
-            args.extend(['--enable-shared', '--enable-static'])
+        args.append('--enable-static' if 'libs=static' in self.spec
+                    else '--disable-static')
+        args.append('--enable-shared' if 'libs=shared' in self.spec
+                    else '--disable-shared')
 
         configure(*args)