Add project metadata for local saved state

Summary:
Add a project metadata field to all saved state implementations that
can be used to differentiate multiple saved states for a given project at a
given source control revision. For example, a tool using saved states might
want multiple saved states for a particular revision, one for each supported
version of the tool.

Update the local saved state interface to use the project metadata, if
specified, by appending it, separated by an underscore, to the end of the hash
in the filename.

Reviewed By: wez

Differential Revision: D14789784

fbshipit-source-id: d92d730e4362ff0d8eb1791b840c632ba14be539

saved_state/LocalSavedStateInterface.cpp

@@ -80,6 +80,12 @@ LocalSavedStateInterface::getMostRecentSavedStateImpl(
 }
 
 w_string LocalSavedStateInterface::getLocalPath(w_string_piece commitId) const {
-  return w_string::pathCat({localStoragePath_, project_, commitId});
+  w_string filename;
+  if (!projectMetadata_) {
+    filename = w_string::build(commitId);
+  } else {
+    filename = w_string::build(commitId, w_string("_"), projectMetadata_);
+  }
+  return w_string::pathCat({localStoragePath_, project_, filename});
 }
 } // namespace watchman

saved_state/LocalSavedStateInterface.h

@@ -10,7 +10,10 @@ namespace watchman {
 // stored on the local filesystem. The local storage path must contain a
 // subdirectory for the project, and within the project directory the saved
 // state for a given commit must be in a file whose name is the source control
-// commit hash.
+// commit hash. If project metadata is not specified, then only saved states
+// with no project metadata will be returned. If project metadata is specified,
+// then the most recent saved state with the specified project metadata will be
+// returned.
 //
 // Checks the most recent n commits to find a saved state, if available. If a
 // saved state is not available, returns an error message in the saved state

saved_state/SavedStateInterface.cpp

@@ -39,6 +39,15 @@ SavedStateInterface::SavedStateInterface(const json_ref& savedStateConfig) {
     throw QueryParseError("'project' must be a string");
   }
   project_ = json_to_w_string(project);
+  auto projectMetadata = savedStateConfig.get_default("project-metadata");
+  if (projectMetadata) {
+    if (!projectMetadata.isString()) {
+      throw QueryParseError("'project-metadata' must be a string");
+    }
+    projectMetadata_ = json_to_w_string(projectMetadata);
+  } else {
+    projectMetadata_ = w_string();
+  }
 }
 
 SavedStateInterface::SavedStateResult

saved_state/SavedStateInterface.h

@@ -46,6 +46,7 @@ class SavedStateInterface {
 
  protected:
   w_string project_;
+  w_string projectMetadata_;
 
   explicit SavedStateInterface(const json_ref& savedStateConfig);
   virtual SavedStateResult getMostRecentSavedStateImpl(

tests/LocalSavedStateInterfaceTest.cpp

@@ -89,6 +89,21 @@ void test_project() {
   ok(true, "expected constructor to succeed");
 }
 
+void test_project_metadata() {
+  auto localStoragePath = w_string_to_json("/absolute/path");
+  expect_query_parse_error(
+      json_object({{"local-storage-path", localStoragePath},
+                   {"project", w_string_to_json("relative/path")},
+                   {"project-metadata", json_integer(5)}}),
+      "failed to parse query: 'project-metadata' must be a string");
+  LocalSavedStateInterface interface(
+      json_object({{"local-storage-path", localStoragePath},
+                   {"project", w_string_to_json("foo")},
+                   {"project-metadata", w_string_to_json("meta")}}),
+      nullptr);
+  ok(true, "expected constructor to succeed");
+}
+
 void test_path() {
   auto localStoragePath = w_string_to_json("/absolute/path");
   LocalSavedStateInterface interface(
@@ -101,13 +116,25 @@ void test_path() {
      "Expected path to be \"%s\" but observed \"%s\"",
      expectedPath,
      path.c_str());
+  interface = LocalSavedStateInterface(
+      json_object({{"local-storage-path", localStoragePath},
+                   {"project", w_string_to_json("foo")},
+                   {"project-metadata", w_string_to_json("meta")}}),
+      nullptr);
+  path = interface.getLocalPath("hash");
+  expectedPath = "/absolute/path/foo/hash_meta";
+  ok(!strcmp(path.c_str(), expectedPath),
+     "Expected path to be \"%s\" but observed \"%s\"",
+     expectedPath,
+     path.c_str());
 }
 
 int main(int, char**) {
-  plan_tests(22);
+  plan_tests(26);
   test_max_commits();
   test_localStoragePath();
   test_project();
+  test_project_metadata();
   test_path();
 
   return exit_status();

tests/integration/test_local_saved_state.py

@@ -119,14 +119,20 @@ def getQuery(self, config):
             },
         }
 
+    def getLocalFilename(self, saved_state_rev, metadata):
+        if metadata:
+            return saved_state_rev + "_" + metadata
+        return saved_state_rev
+
     # Creates a saved state (with no content) for the specified project at the
     # specified bookmark within the specified local storage path.
-    def saveState(self, project, bookmark, local_storage):
+    def saveState(self, project, bookmark, local_storage, metadata=None):
         saved_state_rev = self.resolveCommitHash(bookmark, cwd=self.root)
         project_dir = os.path.join(local_storage, project)
         if not os.path.isdir(project_dir):
             os.mkdir(project_dir)
-        self.touchRelative(project_dir, saved_state_rev)
+        filename = self.getLocalFilename(saved_state_rev, metadata)
+        self.touchRelative(project_dir, filename)
         return saved_state_rev
 
     def getConfig(self, result):
@@ -229,6 +235,70 @@ def test_localSavedStateLookupSuccess(self):
         self.assertSavedStateInfo(res, expected_path, saved_state_rev_feature3)
         self.assertFileListsEqual(res["files"], ["f1", "bar", "car"])
 
+    def test_localSavedStateLookupSuccessWithMetadata(self):
+        local_storage = self.mkdtemp()
+        metadata = "metadata"
+        saved_state_rev_feature3 = self.saveState(
+            "example_project", "feature3", local_storage, metadata
+        )
+        self.saveState("example_project", "feature0", local_storage, metadata)
+        config = {
+            "local-storage-path": local_storage,
+            "project": "example_project",
+            "project-metadata": metadata,
+            "max-commits": 10,
+        }
+        test_query = self.getQuery(config)
+        res = self.watchmanCommand("query", self.root, test_query)
+        expected_mergebase = self.resolveCommitHash("TheMaster", cwd=self.root)
+        self.assertMergebaseEquals(res, expected_mergebase)
+        self.assertStorageTypeLocal(res)
+        self.assertCommitIDEquals(res, saved_state_rev_feature3)
+        self.assertEqual(self.getConfig(res), config)
+        project_dir = os.path.join(local_storage, "example_project")
+        filepath = self.getLocalFilename(saved_state_rev_feature3, metadata)
+        expected_path = os.path.join(project_dir, filepath)
+        self.assertSavedStateInfo(res, expected_path, saved_state_rev_feature3)
+        self.assertFileListsEqual(res["files"], ["f1", "bar", "car"])
+
+    def test_localSavedStateFailureIfMetadataDoesNotMatch(self):
+        local_storage = self.mkdtemp()
+        self.saveState("example_project", "feature3", local_storage)
+        self.saveState("example_project", "feature0", local_storage)
+        config = {
+            "local-storage-path": local_storage,
+            "project": "example_project",
+            "project-metadata": "meta",
+            "max-commits": 10,
+        }
+        test_query = self.getQuery(config)
+        res = self.watchmanCommand("query", self.root, test_query)
+        self.assertSavedStateErrorEquals(res, "No suitable saved state found")
+        self.assertEqual(self.getConfig(res), config)
+        self.assertStorageTypeLocal(res)
+        expected_mergebase = self.resolveCommitHash("TheMaster", cwd=self.root)
+        self.assertMergebaseEquals(res, expected_mergebase)
+        self.assertFileListsEqual(res["files"], ["foo", "p1", "m2", "bar", "car", "f1"])
+
+    def test_localSavedStateFailureIfNoMetadataForFileThatHasIt(self):
+        local_storage = self.mkdtemp()
+        metadata = "metadata"
+        self.saveState("example_project", "feature3", local_storage, metadata)
+        self.saveState("example_project", "feature0", local_storage, metadata)
+        config = {
+            "local-storage-path": local_storage,
+            "project": "example_project",
+            "max-commits": 10,
+        }
+        test_query = self.getQuery(config)
+        res = self.watchmanCommand("query", self.root, test_query)
+        self.assertSavedStateErrorEquals(res, "No suitable saved state found")
+        self.assertEqual(self.getConfig(res), config)
+        self.assertStorageTypeLocal(res)
+        expected_mergebase = self.resolveCommitHash("TheMaster", cwd=self.root)
+        self.assertMergebaseEquals(res, expected_mergebase)
+        self.assertFileListsEqual(res["files"], ["foo", "p1", "m2", "bar", "car", "f1"])
+
     def test_localSavedStateSubscription(self):
         local_storage = self.mkdtemp()
         saved_state_rev_feature3 = self.saveState(