Produce a single library for multiple file dependencies on the same file

Previously, the Gradle plugin’s ProjectLibraries produced a new library
for every file dependency, even if the dependencies where on the same
file. This would lead to a repackaging failure due to multiple
libraries having the same name.

This commit updates ProjectLibraries to treat file dependencies on the
same file as a single library, thereby resolving the name clash.

Fixes gh-1646

spring-boot-tools/spring-boot-gradle-plugin/src/main/groovy/org/springframework/boot/gradle/repackage/ProjectLibraries.java

@@ -199,6 +199,23 @@ class ProjectLibraries implements Libraries {
 			return name;
 		}
 
+		@Override
+		public int hashCode() {
+			return getFile().hashCode();
+		}
+
+		@Override
+		public boolean equals(Object obj) {
+			if (obj instanceof GradleLibrary) {
+				return getFile().equals(((GradleLibrary) obj).getFile());
+			}
+			return false;
+		}
+
+		@Override
+		public String toString() {
+			return getFile().getAbsolutePath();
+		}
 	}
 
 	/**