From b899da6637a5152fc13be5b89688c5f70c85563d Mon Sep 17 00:00:00 2001
From: Jeff Ching <chingor@google.com>
Date: Mon, 10 Apr 2023 15:18:49 -0700
Subject: [PATCH] fix(xml): preserve trailing newline if the xml file had one
 (#1911)

* test: failing test for preserving newlines

* fix(xml): preserve trailing newline if the xml file had one
---
 __snapshots__/pom-xml.js                      | 86 +++++++++++++++++++
 src/updaters/base-xml.ts                      |  6 +-
 .../fixtures/pom-trailing-newline.xml         | 81 +++++++++++++++++
 test/updaters/pom-xml.ts                      | 10 +++
 4 files changed, 182 insertions(+), 1 deletion(-)
 create mode 100644 test/updaters/fixtures/pom-trailing-newline.xml

diff --git a/__snapshots__/pom-xml.js b/__snapshots__/pom-xml.js
index ea0287e73..121b3770c 100644
--- a/__snapshots__/pom-xml.js
+++ b/__snapshots__/pom-xml.js
@@ -1,3 +1,88 @@
+exports['PomXml updateContent preserves trailing newlines 1'] = `
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <parent>
+    <groupId>com.google.auth</groupId>
+    <artifactId>google-auth-library-parent</artifactId>
+    <version>0.16.2</version><!-- {x-version-update:google-auth-library-parent:current} -->
+    <relativePath>../pom.xml</relativePath>
+  </parent>
+
+  <groupId>com.google.auth</groupId>
+  <artifactId>google-auth-library-appengine</artifactId>
+  <version>2.3.4</version><!-- {x-version-update:google-auth-library-parent:current} -->
+  <name>Google Auth Library for Java - Google App Engine</name>
+
+  <distributionManagement>
+    <snapshotRepository>
+      <id>ossrh</id>
+      <url>https://oss.sonatype.org/content/repositories/snapshots</url>
+    </snapshotRepository>
+  </distributionManagement>
+
+  <build>
+    <sourceDirectory>java</sourceDirectory>
+    <testSourceDirectory>javatests</testSourceDirectory>
+    <plugins>
+      <plugin>
+        <groupId>org.sonatype.plugins</groupId>
+        <artifactId>nexus-staging-maven-plugin</artifactId>
+      </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-source-plugin</artifactId>
+      </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-javadoc-plugin</artifactId>
+      </plugin>
+    </plugins>
+  </build>
+
+  <dependencies>
+    <dependency>
+      <groupId>com.google.auth</groupId>
+      <artifactId>google-auth-library-credentials</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>com.google.auth</groupId>
+      <artifactId>google-auth-library-oauth2-http</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>com.google.http-client</groupId>
+      <artifactId>google-http-client</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>com.google.http-client</groupId>
+      <artifactId>google-http-client-jackson2</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>com.google.appengine</groupId>
+      <artifactId>appengine-api-1.0-sdk</artifactId>
+      <scope>provided</scope>
+    </dependency>
+    <dependency>
+      <groupId>com.google.guava</groupId>
+      <artifactId>guava</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>com.google.auth</groupId>
+      <artifactId>google-auth-library-oauth2-http</artifactId>
+      <type>test-jar</type>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+</project>
+
+`
+
 exports['PomXml updateContent updates dependencies 1'] = `
 <?xml version="1.0" encoding="UTF-8"?>
 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
@@ -67,6 +152,7 @@ exports['PomXml updateContent updates project.parent.version 1'] = `
 
   <artifactId>google-auth-library-appengine</artifactId>
 </project>
+
 `
 
 exports['PomXml updateContent updates project.version 1'] = `
diff --git a/src/updaters/base-xml.ts b/src/updaters/base-xml.ts
index f5fbad4e8..3930bbeec 100644
--- a/src/updaters/base-xml.ts
+++ b/src/updaters/base-xml.ts
@@ -29,7 +29,11 @@ export abstract class BaseXml implements Updater {
     const updated = this.updateDocument(document);
 
     if (updated) {
-      return new dom.XMLSerializer().serializeToString(document);
+      const newContent = new dom.XMLSerializer().serializeToString(document);
+      if (content.endsWith('\n') && !newContent.endsWith('\n')) {
+        return `${newContent}\n`;
+      }
+      return newContent;
     } else {
       return content;
     }
diff --git a/test/updaters/fixtures/pom-trailing-newline.xml b/test/updaters/fixtures/pom-trailing-newline.xml
new file mode 100644
index 000000000..e8b4118b0
--- /dev/null
+++ b/test/updaters/fixtures/pom-trailing-newline.xml
@@ -0,0 +1,81 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <parent>
+    <groupId>com.google.auth</groupId>
+    <artifactId>google-auth-library-parent</artifactId>
+    <version>0.16.2</version><!-- {x-version-update:google-auth-library-parent:current} -->
+    <relativePath>../pom.xml</relativePath>
+  </parent>
+
+  <groupId>com.google.auth</groupId>
+  <artifactId>google-auth-library-appengine</artifactId>
+  <version>0.16.2</version><!-- {x-version-update:google-auth-library-parent:current} -->
+  <name>Google Auth Library for Java - Google App Engine</name>
+
+  <distributionManagement>
+    <snapshotRepository>
+      <id>ossrh</id>
+      <url>https://oss.sonatype.org/content/repositories/snapshots</url>
+    </snapshotRepository>
+  </distributionManagement>
+
+  <build>
+    <sourceDirectory>java</sourceDirectory>
+    <testSourceDirectory>javatests</testSourceDirectory>
+    <plugins>
+      <plugin>
+        <groupId>org.sonatype.plugins</groupId>
+        <artifactId>nexus-staging-maven-plugin</artifactId>
+      </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-source-plugin</artifactId>
+      </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-javadoc-plugin</artifactId>
+      </plugin>
+    </plugins>
+  </build>
+
+  <dependencies>
+    <dependency>
+      <groupId>com.google.auth</groupId>
+      <artifactId>google-auth-library-credentials</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>com.google.auth</groupId>
+      <artifactId>google-auth-library-oauth2-http</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>com.google.http-client</groupId>
+      <artifactId>google-http-client</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>com.google.http-client</groupId>
+      <artifactId>google-http-client-jackson2</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>com.google.appengine</groupId>
+      <artifactId>appengine-api-1.0-sdk</artifactId>
+      <scope>provided</scope>
+    </dependency>
+    <dependency>
+      <groupId>com.google.guava</groupId>
+      <artifactId>guava</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>com.google.auth</groupId>
+      <artifactId>google-auth-library-oauth2-http</artifactId>
+      <type>test-jar</type>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+</project>
diff --git a/test/updaters/pom-xml.ts b/test/updaters/pom-xml.ts
index e218dd856..32004f10c 100644
--- a/test/updaters/pom-xml.ts
+++ b/test/updaters/pom-xml.ts
@@ -59,5 +59,15 @@ describe('PomXml', () => {
       const newContent = updater.updateContent(oldContent);
       snapshot(newContent);
     });
+
+    it('preserves trailing newlines', async () => {
+      const oldContent = readFileSync(
+        resolve(fixturesPath, './pom-trailing-newline.xml'),
+        'utf8'
+      ).replace(/\r\n/g, '\n');
+      const updater = new PomXml(Version.parse('v2.3.4'));
+      const newContent = updater.updateContent(oldContent);
+      snapshot(newContent);
+    });
   });
 });