interpreter: Cache found dependency before converting for include_type

Fixes: #8516.

mesonbuild/interpreter.py

@@ -3775,13 +3775,6 @@ external dependencies (including libraries) must go to "dependencies".''')
         if not d.found() and not_found_message:
             self.message_impl([not_found_message])
             self.message_impl([not_found_message])
-        # Ensure the correct include type
-        if 'include_type' in kwargs:
-            wanted = kwargs['include_type']
-            actual = d.include_type_method([], {})
-            if wanted != actual:
-                mlog.debug('Current include type of {} is {}. Converting to requested {}'.format(name, actual, wanted))
-                d = d.as_system_method([wanted], {})
         # Override this dependency to have consistent results in subsequent
         # dependency lookups.
         if name and d.found():
@@ -3790,6 +3783,13 @@ external dependencies (including libraries) must go to "dependencies".''')
             if identifier not in self.build.dependency_overrides[for_machine]:
                 self.build.dependency_overrides[for_machine][identifier] = \
                     build.DependencyOverride(d.held_object, node, explicit=False)
+        # Ensure the correct include type
+        if 'include_type' in kwargs:
+            wanted = kwargs['include_type']
+            actual = d.include_type_method([], {})
+            if wanted != actual:
+                mlog.debug('Current include type of {} is {}. Converting to requested {}.format(name, actual, wanted)')
+                d = d.as_system_method([wanted], {})
         return d
 
     def dependency_impl(self, name, display_name, kwargs, force_fallback=False):

test cases/common/239 dependency include_type inconsistency/bar/meson.build

@@ -0,0 +1,5 @@
+baz_dep = dependency('baz',
+    fallback: ['baz', 'baz_dep'],
+    include_type: 'system',
+    method: 'pkg-config', # if we comment this out or change to 'auto' the build is successful
+    required: false)

test cases/common/239 dependency include_type inconsistency/meson.build

@@ -0,0 +1,5 @@
+project('test', 'c', 'cpp')
+
+foo_dep = subproject('foo').get_variable('foo_dep')
+
+subdir('bar')

test cases/common/239 dependency include_type inconsistency/subprojects/baz.wrap

@@ -0,0 +1,3 @@
+[wrap-file]
+source_url = http://host.invalid/baz.tar.gz
+source_filename = baz.tar.gz

test cases/common/239 dependency include_type inconsistency/subprojects/baz/meson.build

@@ -0,0 +1,3 @@
+project('baz', 'cpp')
+
+baz_dep = declare_dependency()

test cases/common/239 dependency include_type inconsistency/subprojects/foo.wrap

@@ -0,0 +1,3 @@
+[wrap-file]
+source_url = http://host.invalid/foo.tar.gz
+source_filename = foo.tar.gz

test cases/common/239 dependency include_type inconsistency/subprojects/foo/meson.build

@@ -0,0 +1,9 @@
+project('foo', 'c', 'cpp')
+
+baz_dep = dependency('baz',
+    fallback: ['baz', 'baz_dep'],
+    include_type: 'system',
+    method: 'pkg-config',
+    required: false)
+
+foo_dep = declare_dependency(dependencies: baz_dep)