Only adjust .idea/vcs.xml if it exists (#532)

While working on #491, I saw that buildSrc/build.gradle was
failing if the .idea directory existed but .idea/vcs.xml did not,
which is what was happened for me with my version of IntelliJ IDEA.

This commit makes the build script more lenient by only trying to
append issue-related XML tags to .idea/vcs.xml if it exists,
rather than relying on the presence of just the .idea directory.

Related discussion: #491
PR: #532

README.md

@@ -117,9 +117,10 @@ The least we can do is to thank them and list some of their accomplishments here
 
 * [Cory Thomas](https://github.com/dump247) contributed the `minSuccess` attribute in [retrying tests](https://junit-pioneer.org/docs/retrying-test/) (#408 / #430)
 * [Daniel Kraus](https://github.com/beatngu13) fixed bugs in the environment variable and system property extensions (#432 / #433, #448 / #449, and more), revamped their annotation handling (#460 / #485), and improved the build process (#482 / #483) before becoming a maintainer
-*  [John Lehne](https://github.com/johnlehne) resolved an issue with the latest build status not showing correctly in README.md (#530)
+* [John Lehne](https://github.com/johnlehne) resolved an issue with the latest build status not showing correctly in README.md (#530)
 * [Slawomir Jaranowski](https://github.com/slawekjaranowski) Migrate to new Shipkit plugins (#410 / #419)
 * [Stefano Cordio](https://github.com/scordio) contributed [the Cartesian Enum source](https://junit-pioneer.org/docs/cartesian-product/#cartesianenumsource) (#379 / #409 and #414 / #453)
+* [Jonathan Bluett-Duncan](https://github.com/jbduncan) contributed a fix to `buildSrc/build.gradle` which was failing when a `.idea` directory did not contain a `vcs.xml` file (#532)
 
 #### 2020
 

buildSrc/build.gradle

@@ -3,24 +3,26 @@ import groovy.xml.XmlUtil
 build {
 	doLast {
 		def ideaFolder = new File('.idea');
-		if(ideaFolder.exists() && ideaFolder.isDirectory()) {
+		if (ideaFolder.exists() && ideaFolder.isDirectory()) {
 			def xmlFile = new File(".idea/vcs.xml")
-			def xml = new XmlSlurper().parse(xmlFile)
-			xml.component.find {it.@name == 'IssueNavigationConfiguration'}.replaceNode {}
-			xml.appendNode {
-				component(name: "IssueNavigationConfiguration") {
-					option(name: 'links') {
-						list {
-							IssueNavigationLink {
-								option(name: "issueRegexp", value: '#(\\d+)')
-								option(name: "linkRegexp", value: 'https://github.com/junit-pioneer/junit-pioneer/issues/$1')
+			if (xmlFile.exists() && xmlFile.isFile()) {
+				def xml = new XmlSlurper().parse(xmlFile)
+				xml.component.find { it.@name == 'IssueNavigationConfiguration' }.replaceNode {}
+				xml.appendNode {
+					component(name: "IssueNavigationConfiguration") {
+						option(name: 'links') {
+							list {
+								IssueNavigationLink {
+									option(name: "issueRegexp", value: '#(\\d+)')
+									option(name: "linkRegexp", value: 'https://github.com/junit-pioneer/junit-pioneer/issues/$1')
+								}
 							}
 						}
 					}
 				}
-			}
-			xmlFile.withWriter {out->
-				XmlUtil.serialize(xml, out)
+				xmlFile.withWriter { out ->
+					XmlUtil.serialize(xml, out)
+				}
 			}
 		}
 	}