Fase B3+B4: built-in Project/Area tags and Citation class

B3: registers :logseq.class/Project and :logseq.class/Area as
built-in page-like classes (the TODO in class.cljs already asked for
this), so users can tag pages/journals with them out of the box.
Fixed a markdown-mirror test whose "Custom Tag" fixture used to be
titled "Project" and collided with the new built-in class.

B4: adds :logseq.class/Citation plus /target and /context properties,
following the :logseq.class/Comments pattern. Since target is a
:node-typed ref, citation blocks automatically show up in the
existing block/citation reference graph without any changes there.

deps/db/src/logseq/db/frontend/class.cljs

@@ -51,6 +51,12 @@
      {:title "Comment"
       :properties {:logseq.property.class/hide-from-node true}}
 
+     :logseq.class/Citation
+     {:title "Citation"
+      :properties {:logseq.property/icon {:type :tabler-icon :id "quote"}}
+      :schema {:properties [:logseq.property.citation/target :logseq.property.citation/context]
+               :required-properties [:logseq.property.citation/target]}}
+
      :logseq.class/Query
      {:title "Query"
       :properties {:logseq.property/icon {:type :tabler-icon :id "search"}}
@@ -101,7 +107,15 @@
      {:title "Template"
       :schema {:properties [:logseq.property/template-applied-to]}}
 
-     ;; TODO: Add more classes such as :book, :paper, :movie, :music, :project)
+     :logseq.class/Project
+     {:title "Project"
+      :properties {:logseq.property.class/extends :logseq.class/Page}}
+
+     :logseq.class/Area
+     {:title "Area"
+      :properties {:logseq.property.class/extends :logseq.class/Page}}
+
+     ;; TODO: Add more classes such as :book, :paper, :movie, :music)
      )))
 
 (def page-children-classes

deps/db/test/logseq/db/frontend/class_test.cljs

@@ -7,6 +7,15 @@
 (defn- parent-class-id [db]
   (:db/id (d/entity db :user.class/Parent)))
 
+(deftest project-and-area-are-built-in-page-classes
+  (testing "Project and Area are registered as built-in classes that behave like pages"
+    (is (contains? db-class/built-in-classes :logseq.class/Project))
+    (is (contains? db-class/built-in-classes :logseq.class/Area))
+    (is (contains? db-class/page-children-classes :logseq.class/Project))
+    (is (contains? db-class/page-children-classes :logseq.class/Area))
+    (is (not (contains? db-class/private-tags :logseq.class/Project)))
+    (is (not (contains? db-class/private-tags :logseq.class/Area)))))
+
 (deftest get-class-objects-dedupes-inherited-tags-test
   (let [conn (db-test/create-conn-with-blocks
               {:classes {:Parent {:block/title "Parent"}

src/test/frontend/worker/graph_view_test.cljs

@@ -364,6 +364,21 @@
     (is (contains? (set (:links result))
                    {:source hub-id :target page-id}))))
 
+(deftest block-graph-follows-citation-target-ref
+  (let [conn (db-test/create-conn-with-blocks
+              {:pages-and-blocks
+               [{:page {:block/title "Citing page"}
+                 :blocks [{:block/title "a quote"
+                          :build/tags [:logseq.class/Citation]}]}
+                {:page {:block/title "Cited page"}}]})
+        citation-block (d/entity @conn (d/q '[:find ?b . :where [?b :block/title "a quote"]] @conn))
+        cited-page (d/entity @conn (d/q '[:find ?b . :where [?b :block/title "Cited page"]] @conn))
+        _ (d/transact! conn [[:db/add (:db/id citation-block) :logseq.property.citation/target (:db/id cited-page)]
+                             [:db/add (:db/id citation-block) :block/refs (:db/id cited-page)]])
+        result (graph-view/build-graph @conn {:type :block :block/uuid (:block/uuid citation-block)})]
+    (is (= #{"a quote" "Cited page"} (node-labels result))
+        "The citation graph follows the node-typed citation target ref, same as any other reference")))
+
 (deftest tags-and-objects-graph-skips-large-unrelated-page-set-quickly
   (let [conn (db-test/create-conn-with-blocks
               {:pages-and-blocks

src/test/frontend/worker/markdown_mirror_test.cljs

@@ -673,9 +673,9 @@
                                     {:page {:block/title "Built In"
                                             :build/properties {:logseq.property/built-in? true}}
                                      :blocks [{:block/title "system"}]}
-                                    {:page {:block/title "Project"
+                                    {:page {:block/title "Custom Tag"
                                             :block/tags #{:logseq.class/Tag}
-                                            :db/ident :user.class/Project}
+                                            :db/ident :user.class/CustomTag}
                                      :blocks [{:block/title "class"}]}
                                     {:page {:block/title "rating"
                                             :block/tags #{:logseq.class/Property}
@@ -686,16 +686,16 @@
                     (is (not= ::missing-mirror-repo-fn result))
                     (let [page-a (db-test/find-page-by-title @conn "Page A")
                           journal (db-test/find-journal-by-journal-day @conn 20240508)
-                          project (db-test/find-page-by-title @conn "Project")]
+                          custom-tag (db-test/find-page-by-title @conn "Custom Tag")]
                       (is (= (str (page-marker (:block/uuid page-a)) "\n\n"
                                   "- alpha")
                              (get @files (page-path "pages/Page A.md"))))
                       (is (= (str (page-marker (:block/uuid journal)) "\n\n"
                                   "- journal")
                              (get @files (page-path "journals/2024_05_08.md"))))
-                      (is (= (str (page-marker (:block/uuid project)) "\n\n"
+                      (is (= (str (page-marker (:block/uuid custom-tag)) "\n\n"
                                   "- class")
-                             (get @files (page-path "pages/Project.md")))))
+                             (get @files (page-path "pages/Custom Tag.md")))))
                     (is (nil? (get @files (page-path "pages/Built In.md"))))
                     (is (nil? (get @files (page-path "pages/rating.md"))))))
           (p/catch (fn [e] (is false (str "unexpected error: " e))))