Ensure topo sort works with partial graphs

kepler16 · Sep 4, 2024 · 4d77a9d · 4d77a9d
1 parent 8e099ba
commit 4d77a9d
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Showing 2 changed files with 25 additions and 17 deletions.
diff --git a/packages/kmono-core/src/k16/kmono/core/graph.clj b/packages/kmono-core/src/k16/kmono/core/graph.clj
@@ -34,21 +34,27 @@
 (defn parallel-topo-sort
   {:malli/schema [:=> [:cat core.schema/?PackageMap] [:maybe ?ExecOrder]]}
   [packages]
-  (when (seq packages)
-    (when-let [ks (->> packages
-                       (keep
-                        (fn [[fqn package]]
-                          (when (empty? (:depends-on package))
-                            fqn)))
-                       seq
-                       sort)]
-      (into [(vec ks)]
-            (parallel-topo-sort
-             (into {}
-                   (map (fn [[fqn package]]
-                          [fqn (assoc package
-                                      :depends-on (apply disj (:depends-on package) ks))]))
-                   (apply dissoc packages ks)))))))
+  (let [stage
+        (into #{}
+              (comp
+               (filter (fn [[_ pkg]]
+                         (empty? (:depends-on pkg))))
+               (map first))
+              packages)
+
+        remaining
+        (reduce
+         (fn [packages [pkg-name pkg]]
+           (if-not (contains? stage pkg-name)
+             (let [deps (apply disj (:depends-on pkg) stage)
+                   pkg (assoc pkg :depends-on deps)]
+               (assoc packages pkg-name pkg))
+             packages))
+         {}
+         packages)]
+
+    (when (seq stage)
+      (into [(-> stage sort vec)] (parallel-topo-sort remaining)))))
 
 (defn query-dependents
   {:malli/schema [:=> [:cat core.schema/?PackageMap :symbol] [:set :symbol]]}

diff --git a/packages/kmono-core/test/k16/kmono/core/graph_test.clj b/packages/kmono-core/test/k16/kmono/core/graph_test.clj
@@ -46,7 +46,9 @@
         packages (core.packages/resolve-packages *repo* config)]
 
     (is (= [['com.kepler16/b]]
-           (core.graph/parallel-topo-sort (dissoc packages 'com.kepler16/a))))))
+           (core.graph/parallel-topo-sort
+            (core.graph/filter-by #(= 'com.kepler16/b (:fqn %))
+                                  packages))))))
 
 (deftest query-dependents-test
   (fs/create-dirs (fs/file *repo* "packages/c"))
@@ -73,7 +75,7 @@
     (is (match? {'com.kepler16/a {:dependents #{}}}
                 (core.graph/filter-by #(= 'com.kepler16/a (:fqn %)) packages)))
 
-(is (match? {'com.kepler16/b {:depends-on #{}}}
+    (is (match? {'com.kepler16/b {:depends-on #{}}}
                 (core.graph/filter-by #(= 'com.kepler16/b (:fqn %)) packages)))
 
     (is (= ['com.kepler16/b 'com.kepler16/a]