Warn if wrap file changes

Save off the hash of the wrap file when first configuring a subproject.
When reconfiguring a subproject, check the hash of the wrap file
against the stored hash. If they don't match then warn the user.

mesonbuild/msubprojects.py

@@ -394,19 +394,22 @@ class Runner:
 
     def update(self) -> bool:
         self.log(f'Updating {self.wrap.name}...')
+        success = False
         if self.wrap.type == 'file':
-            return self.update_file()
+            success = self.update_file()
         elif self.wrap.type == 'git':
-            return self.update_git()
+            success = self.update_git()
         elif self.wrap.type == 'hg':
-            return self.update_hg()
+            success = self.update_hg()
         elif self.wrap.type == 'svn':
-            return self.update_svn()
+            success = self.update_svn()
         elif self.wrap.type is None:
             self.log('  -> Cannot update subproject with no wrap file')
         else:
             self.log('  -> Cannot update', self.wrap.type, 'subproject')
-        return True
+        if success:
+            self.wrap.update_hash_cache(self.wrap_resolver.dirname)
+        return success
 
     def checkout(self) -> bool:
         options = T.cast('CheckoutArguments', self.options)

mesonbuild/wrap/wrap.py

@@ -132,7 +132,9 @@ class PackageDefinition:
         self.redirected = False
         if self.has_wrap:
             self.parse_wrap()
-        self.directory = self.values.get('directory', self.name)
+            self.directory = self.values.get('directory', self.name)
+            with open(fname, 'r', encoding='utf-8') as file:
+                self.wrapfile_hash = hashlib.sha256(file.read().encode('utf-8')).hexdigest()
         if os.path.dirname(self.directory):
             raise WrapException('Directory key must be a name and not a path')
         if self.type and self.type not in ALL_TYPES:
@@ -221,6 +223,14 @@ class PackageDefinition:
         except KeyError:
             raise WrapException(f'Missing key {key!r} in {self.basename}')
 
+    def get_hashfile(self, subproject_directory: str) -> str:
+        return os.path.join(subproject_directory, '.meson-subproject-wrap-hash.txt')
+
+    def update_hash_cache(self, subproject_directory: str) -> None:
+        if self.has_wrap:
+            with open(self.get_hashfile(subproject_directory), 'w', encoding='utf-8') as file:
+                file.write(self.wrapfile_hash + '\n')
+
 def get_directory(subdir_root: str, packagename: str) -> str:
     fname = os.path.join(subdir_root, packagename + '.wrap')
     if os.path.isfile(fname):
@@ -367,6 +377,7 @@ class Resolver:
 
         # The directory is there and has meson.build? Great, use it.
         if method == 'meson' and os.path.exists(meson_file):
+            self.validate()
             return rel_path
         if method == 'cmake' and os.path.exists(cmake_file):
             return rel_path
@@ -403,6 +414,11 @@ class Resolver:
         if method == 'cmake' and not os.path.exists(cmake_file):
             raise WrapException('Subproject exists but has no CMakeLists.txt file')
 
+        # At this point, the subproject has been successfully resolved for the
+        # first time so save off the hash of the entire wrap file for future
+        # reference.
+        self.wrap.update_hash_cache(self.dirname)
+
         return rel_path
 
     def check_can_download(self) -> None:
@@ -504,6 +520,26 @@ class Resolver:
             if push_url:
                 verbose_git(['remote', 'set-url', '--push', 'origin', push_url], self.dirname, check=True)
 
+    def validate(self) -> None:
+        # This check is only for subprojects with wraps.
+        if not self.wrap.has_wrap:
+            return
+
+        # Retrieve original hash, if it exists.
+        hashfile = self.wrap.get_hashfile(self.dirname)
+        if os.path.isfile(hashfile):
+            with open(hashfile, 'r', encoding='utf-8') as file:
+                expected_hash = file.read().strip()
+        else:
+            # If stored hash doesn't exist then don't warn.
+            return
+
+        actual_hash = self.wrap.wrapfile_hash
+
+        # Compare hashes and warn the user if they don't match.
+        if expected_hash != actual_hash:
+            mlog.warning(f'Subproject {self.wrap.name}\'s revision may be out of date; its wrap file has changed since it was first configured')
+
     def is_git_full_commit_id(self, revno: str) -> bool:
         result = False
         if len(revno) in (40, 64): # 40 for sha1, 64 for upcoming sha256

unittests/allplatformstests.py

@@ -3733,10 +3733,26 @@ class AllPlatformTests(BasePlatformTests):
                   patch_directory = wrap_git_builddef
                   revision = master
                 '''.format(upstream_uri)))
-            self.init(srcdir)
+            out = self.init(srcdir)
             self.build()
             self.run_tests()
 
+            # Make sure the warning does not occur on the first init.
+            out_of_date_warning = 'revision may be out of date'
+            self.assertNotIn(out_of_date_warning, out)
+
+            # Change the wrap's revisions, reconfigure, and make sure it does
+            # warn on the reconfigure.
+            with open(os.path.join(srcdir, 'subprojects', 'wrap_git.wrap'), 'w', encoding='utf-8') as f:
+                f.write(textwrap.dedent('''
+                  [wrap-git]
+                  url = {}
+                  patch_directory = wrap_git_builddef
+                  revision = not-master
+                '''.format(upstream_uri)))
+            out = self.init(srcdir, extra_args='--reconfigure')
+            self.assertIn(out_of_date_warning, out)
+
     def test_extract_objects_custom_target_no_warning(self):
         testdir = os.path.join(self.common_test_dir, '22 object extraction')