wrap: wraps from subprojects can replace directories found with no wrap

If main project finds a directory subprojects/foo with no corresponding
foo.wrap, it creates a dummy PackageDefinition for it. If we later find
a subproject that has foo.wrap, replace the dummy wrap with it.

This happens for example when wrap-redirect have been deleted. It also
happens for subprojects downloaded from some Cargo.lock which does not
create a wrap-redirect.

Avoid loading the same location twice, which can happen when preparing
cargo subprojects.

5 files changed, 42 insertions, 6 deletions

diff --git a/mesonbuild/wrap/wrap.py b/mesonbuild/wrap/wrap.py
index a9d1b7bf6..1cc2cee61 100644
--- a/mesonbuild/wrap/wrap.py
+++ b/mesonbuild/wrap/wrap.py
@@ -354,6 +354,7 @@ class Resolver:
         self.wrapdb: T.Dict[str, T.Any] = {}
         self.wrapdb_provided_deps: T.Dict[str, str] = {}
         self.wrapdb_provided_programs: T.Dict[str, str] = {}
+        self.loaded_dirs: T.Set[str] = set()
         self.load_wraps()
         self.load_netrc()
         self.load_wrapdb()
@@ -395,6 +396,7 @@ class Resolver:
         # Add provided deps and programs into our lookup tables
         for wrap in self.wraps.values():
             self.add_wrap(wrap)
+        self.loaded_dirs.add(self.subdir)
 
     def add_wrap(self, wrap: PackageDefinition) -> None:
         for k in wrap.provided_deps.keys():
@@ -439,16 +441,25 @@ class Resolver:
 
     def _merge_wraps(self, other_resolver: 'Resolver') -> None:
         for k, v in other_resolver.wraps.items():
-            self.wraps.setdefault(k, v)
-        for k, v in other_resolver.provided_deps.items():
-            self.provided_deps.setdefault(k, v)
-        for k, v in other_resolver.provided_programs.items():
-            self.provided_programs.setdefault(k, v)
+            prev_wrap = self.wraps.get(v.directory)
+            if prev_wrap and prev_wrap.type is None and v.type is not None:
+                # This happens when a subproject has been previously downloaded
+                # using a wrap from another subproject and the wrap-redirect got
+                # deleted. In that case, the main project created a bare wrap
+                # for the download directory, but now we have a proper wrap.
+                # It also happens for wraps coming from Cargo.lock files, which
+                # don't create wrap-redirect.
+                del self.wraps[v.directory]
+                del self.provided_deps[v.directory]
+            if k not in self.wraps:
+                self.wraps[k] = v
+                self.add_wrap(v)
 
     def load_and_merge(self, subdir: str, subproject: SubProject) -> None:
-        if self.wrap_mode != WrapMode.nopromote:
+        if self.wrap_mode != WrapMode.nopromote and subdir not in self.loaded_dirs:
             other_resolver = Resolver(self.source_dir, subdir, subproject, self.wrap_mode, self.wrap_frontend, self.allow_insecure, self.silent)
             self._merge_wraps(other_resolver)
+            self.loaded_dirs.add(subdir)
 
     def find_dep_provider(self, packagename: str) -> T.Tuple[T.Optional[str], T.Optional[str]]:
         # Python's ini parser converts all key values to lowercase.
diff --git a/test cases/common/282 wrap override/meson.build b/test cases/common/282 wrap override/meson.build
new file mode 100644
index 000000000..76c84d6a1
--- /dev/null
+++ b/test cases/common/282 wrap override/meson.build
@@ -0,0 +1,8 @@
+project('wrap override')
+
+
+subproject('sub')
+
+# sub has subsub.wrap that provides subsub-1.0 dependency. Even if sub itself
+# does not use it, that dependency should now be available.
+dependency('subsub-1.0')
diff --git a/test cases/common/282 wrap override/subprojects/sub/meson.build b/test cases/common/282 wrap override/subprojects/sub/meson.build
new file mode 100644
index 000000000..abefb30fc
--- /dev/null
+++ b/test cases/common/282 wrap override/subprojects/sub/meson.build
@@ -0,0 +1,7 @@
+project('sub')
+
+# Simulate an optional feature that requires subsub.wrap, but that feature is
+# not enabled.
+if false
+  dependency('subsub-1.0')
+endif
diff --git a/test cases/common/282 wrap override/subprojects/sub/subprojects/subsub.wrap b/test cases/common/282 wrap override/subprojects/sub/subprojects/subsub.wrap
new file mode 100644
index 000000000..85a1a7c51
--- /dev/null
+++ b/test cases/common/282 wrap override/subprojects/sub/subprojects/subsub.wrap
@@ -0,0 +1,5 @@
+[wrap-file]
+
+
+[provide]
+dependency_names = subsub-1.0
diff --git a/test cases/common/282 wrap override/subprojects/subsub/meson.build b/test cases/common/282 wrap override/subprojects/subsub/meson.build
new file mode 100644
index 000000000..668dcb3b0
--- /dev/null
+++ b/test cases/common/282 wrap override/subprojects/subsub/meson.build
@@ -0,0 +1,5 @@
+project('sub')
+
+# This simulates a subproject we previously downloaded using
+# subproject/sub/subproject/subsub.wrap
+meson.override_dependency('subsub-1.0', declare_dependency())