From 6b28d464715b59a096a7f388564d94fe4aab2ceb Mon Sep 17 00:00:00 2001
From: caalador <mikael.grankvist@vaadin.com>
Date: Tue, 21 Sep 2021 10:48:15 +0300
Subject: [PATCH] fix: pinned dependency only adds when modified (#11893)

Do not mark pin if no version is actually
added or changed.
With this npm install will not always be
executed on reload and the copied
modules will not disappear.

Fixes #11888
---
 .../server/frontend/TaskUpdatePackages.java   | 17 ++++++++----
 .../frontend/TaskUpdatePackagesNpmTest.java   | 27 +++++++++++++++++++
 2 files changed, 39 insertions(+), 5 deletions(-)

diff --git a/flow-server/src/main/java/com/vaadin/flow/server/frontend/TaskUpdatePackages.java b/flow-server/src/main/java/com/vaadin/flow/server/frontend/TaskUpdatePackages.java
index 6a9580e26b6..46c94065651 100644
--- a/flow-server/src/main/java/com/vaadin/flow/server/frontend/TaskUpdatePackages.java
+++ b/flow-server/src/main/java/com/vaadin/flow/server/frontend/TaskUpdatePackages.java
@@ -288,11 +288,18 @@ private boolean pinPlatformDependency(JsonObject packageJson,
         final JsonObject vaadinDeps = packageJson.getObject(VAADIN_DEP_KEY)
                 .getObject(DEPENDENCIES);
         final JsonObject packageJsonDeps = packageJson.getObject(DEPENDENCIES);
-        assert vaadinDeps != null; // exists at this point
-        assert packageJsonDeps != null;
-        packageJsonDeps.put(pkg, platformPinnedVersion.getFullVersion());
-        vaadinDeps.put(pkg, platformPinnedVersion.getFullVersion());
-        return true;
+        assert vaadinDeps != null :  "vaadin{ dependencies { } } should exist"; // exists at this point
+        assert packageJsonDeps != null : "dependencies { } should exist";
+        if (!packageJsonDeps.hasKey(pkg) || !vaadinDeps.hasKey(pkg)
+                || !platformPinnedVersion.equals(
+                        new FrontendVersion(packageJsonDeps.getString(pkg)))
+                || !platformPinnedVersion.equals(
+                        new FrontendVersion(vaadinDeps.getString(pkg)))) {
+            packageJsonDeps.put(pkg, platformPinnedVersion.getFullVersion());
+            vaadinDeps.put(pkg, platformPinnedVersion.getFullVersion());
+            return true;
+        }
+        return false;
     }
 
     /**
diff --git a/flow-server/src/test/java/com/vaadin/flow/server/frontend/TaskUpdatePackagesNpmTest.java b/flow-server/src/test/java/com/vaadin/flow/server/frontend/TaskUpdatePackagesNpmTest.java
index 851390b9022..6c7bb11d7e1 100644
--- a/flow-server/src/test/java/com/vaadin/flow/server/frontend/TaskUpdatePackagesNpmTest.java
+++ b/flow-server/src/test/java/com/vaadin/flow/server/frontend/TaskUpdatePackagesNpmTest.java
@@ -464,6 +464,33 @@ public void npmIsInUse_versionsJsonHasVaadinCoreVersionPinned_vaadinCoreVersionI
                 vaadinDependencies.hasKey(VAADIN_CORE_NPM_PACKAGE));
     }
 
+    // #11888
+    @Test
+    public void npmIsInUse_versionsJsonContainsSameVersions_nothingIsModified()
+            throws IOException {
+        String versionJsonString = //@formatter:off
+                "{ \"core\": {"
+                        + "\"vaadin-element-mixin\": {\n"
+                        + "    \"jsVersion\": \"" + PLATFORM_DIALOG_VERSION + "\",\n"
+                        + "    \"npmName\": \"" + VAADIN_DIALOG
+                        + "\"\n"
+                        + "},\n"
+                + "}}},\n";//@formatter:on
+        FileUtils.write(versionJsonFile, versionJsonString,
+                StandardCharsets.UTF_8);
+
+        TaskUpdatePackages task = createTask(
+                createApplicationDependencies());
+        task.execute();
+        Assert.assertTrue("Creation of package.json should be marked with modified", task.modified);
+
+        // Rewriting with the same packages should not mark as modified
+        task = createTask(
+                createApplicationDependencies());
+        task.execute();
+        Assert.assertFalse("PackageJson modified without changes.", task.modified);
+    }
+
     private void createBasicVaadinVersionsJson() {
         createVaadinVersionsJson(PLATFORM_DIALOG_VERSION,
                 PLATFORM_ELEMENT_MIXIN_VERSION, PLATFORM_OVERLAY_VERSION);