From c59a6407f76f16872e8528035bd6dc56bfc11f7a Mon Sep 17 00:00:00 2001
From: David Gil <dgilperez@gmail.com>
Date: Mon, 30 May 2022 21:30:48 +0200
Subject: [PATCH 1/2] test: create a failing case for a wrongly resolved
 dependency chain of multiple links

---
 src/examples/happy/depend-on-dependencies-hub-bis.js |  7 +++++++
 src/examples/happy/depend-on-dependencies-hub.js     |  7 +++++++
 src/pluginus.test.js                                 | 10 +++++++++-
 3 files changed, 23 insertions(+), 1 deletion(-)
 create mode 100644 src/examples/happy/depend-on-dependencies-hub-bis.js
 create mode 100644 src/examples/happy/depend-on-dependencies-hub.js

diff --git a/src/examples/happy/depend-on-dependencies-hub-bis.js b/src/examples/happy/depend-on-dependencies-hub-bis.js
new file mode 100644
index 0000000..e711b72
--- /dev/null
+++ b/src/examples/happy/depend-on-dependencies-hub-bis.js
@@ -0,0 +1,7 @@
+export default {
+  depend: ["DependOnDependenciesHub"],
+
+  create: () => ({
+    dependOn: "hub",
+  }),
+}
diff --git a/src/examples/happy/depend-on-dependencies-hub.js b/src/examples/happy/depend-on-dependencies-hub.js
new file mode 100644
index 0000000..d1fb9d6
--- /dev/null
+++ b/src/examples/happy/depend-on-dependencies-hub.js
@@ -0,0 +1,7 @@
+export default {
+  depend: ["DependOnPlain"],
+
+  create: () => ({
+    dependOn: "hub",
+  }),
+}
diff --git a/src/pluginus.test.js b/src/pluginus.test.js
index 395a701..6625db7 100644
--- a/src/pluginus.test.js
+++ b/src/pluginus.test.js
@@ -23,7 +23,15 @@ test("Happy", async t => {
 
   t.deepEquals(
     Object.keys(plugins).sort(),
-    ["DependOnPlain", "ExplicitName", "Object", "Plain", "PromisePlugin"],
+    [
+      "DependOnDependenciesHub",
+      "DependOnDependenciesHubBis",
+      "DependOnPlain",
+      "ExplicitName",
+      "Object",
+      "Plain",
+      "PromisePlugin",
+    ],
     'given [pluginus called with invalid values in "source" param] should [sanitize and load only valid]'
   )
 

From a97db4ec447dad9e5d0238bb0c7e1498bc00b497 Mon Sep 17 00:00:00 2001
From: David Gil <dgilperez@gmail.com>
Date: Mon, 30 May 2022 23:03:56 +0200
Subject: [PATCH 2/2] feat: use topological sort to deal with slightly more
 complex dependency trees

---
 src/pluginus.js | 42 +++++++++++++++++++++++++++++-------------
 1 file changed, 29 insertions(+), 13 deletions(-)

diff --git a/src/pluginus.js b/src/pluginus.js
index 841180b..98a66dd 100644
--- a/src/pluginus.js
+++ b/src/pluginus.js
@@ -3,8 +3,10 @@
 import fs from "fs"
 import path from "path"
 import {
+  all,
   pipe,
-  sortBy,
+  pick,
+  findWith,
   reduce,
   distinct,
   remove,
@@ -18,7 +20,7 @@ import {
   toLower,
   is,
   isEmpty,
-  has,
+  any,
 } from "@asd14/m"
 
 const capitalizeFirstLetter = string =>
@@ -168,6 +170,30 @@ const resolve = unresolvedPlugins => {
   )(unresolvedPlugins)
 }
 
+// Sort based on dependency topology, using TSort
+// https://en.wikipedia.org/wiki/Topological_sorting
+const tSort = (names, input, start = [], depth = 0) => {
+  const processed = reduce((accum, item) => {
+    const plugin = findWith({ name: item }, {})(input)
+
+    const allDependenciesIncluded = pipe(
+      read("depend", []),
+      all(dependency => any(dependency, pick("name")(accum)))
+    )(plugin)
+
+    if (allDependenciesIncluded) {
+      accum.push(plugin)
+    }
+
+    return accum
+  }, start)(names)
+
+  const nextNames = names.filter(n => !processed.includes(n)),
+    goAgain = nextNames.length !== 0 && depth <= names.length
+
+  return goAgain ? tSort(nextNames, input, processed, depth + 1) : processed
+}
+
 export const pluginus = ({ source, nameFn = defaultNameFn }) =>
   pipeP(
     // Sanitize
@@ -179,17 +205,7 @@ export const pluginus = ({ source, nameFn = defaultNameFn }) =>
     plugins => Promise.all(plugins),
     prepare(nameFn),
 
-    // Sort based on dependency. Plugins without dependencies first
-    sortBy((a, b) => {
-      const aHasB = has(b.name, a.depend)
-      const bHasA = has(a.name, b.depend)
-
-      if (!aHasB && !bHasA) {
-        return a.depend.length > b.depend.length ? 1 : -1
-      }
-
-      return bHasA ? -1 : 1
-    }),
+    plugins => tSort(pick("name", plugins), plugins),
 
     //
     resolve