Fix problem with configuring the Spotless plugin

build.gradle

@@ -114,6 +114,31 @@ task installGitHooks(type: Copy, dependsOn: 'setLocalRepo') {
     into localRepo + "/hooks"
 }
 
+spotless {
+  // Resolve the spottless plugin dependencies from the buildscript repositories rather than the
+  // project repositories.  That way the spotless plugin does not use the locally built version of
+  // checker-qual as a dependency. Without this, errors like the follow are issued when running
+  // a spotless task without a locally-built version of checker-qual.jar:
+  // Could not determine the dependencies of task ':checker-qual:spotlessCheck'.
+  //  > Could not create task ':checker-qual:spotlessJavaCheck'.
+  //     > Could not create task ':checker-qual:spotlessJava'.
+  //        > File signature can only be created for existing regular files, given:
+  //          /Users/smillst/jsr308/checker-framework/checker-qual/build/libs/checker-qual-3.25.1-SNAPSHOT.jar
+  predeclareDepsFromBuildscript()
+}
+
+spotlessPredeclare {
+  // Put all the formatters that have dependencies here.  Without this, errors like the following
+  // will happen:
+  // Could not determine the dependencies of task ':spotlessCheck'.
+  //  > Could not create task ':spotlessJavaCheck'.
+  //     > Could not create task ':spotlessJava'.
+  //        > Add a step with [com.google.googlejavaformat:google-java-format:1.15.0] into the `spotlessPredeclare` block in the root project.
+  java {
+    googleJavaFormat()
+  }
+}
+
 allprojects {
     tasks.withType(JavaCompile).configureEach {
         options.fork = true
@@ -196,6 +221,8 @@ allprojects {
     }
 
     spotless {
+        // If you add any formatters to this block that require dependencies here, then you must also
+        // add them to spotlessPredeclare block.
         format 'misc', {
             // define the files to apply `misc` to
             target '*.gradle', '*.md', '.gitignore'