MINOR: add dependency analysis debugging tasks

Author: Arvind Thirunarayanan <athirunar@confluent.io>

Reviewers: Colin Patrick McCabe <colin@cmccabe.xyz>

Closes #7694 from arvindth/ath-debugdeps-task

README.md

@@ -200,6 +200,18 @@ The following options should be set with a `-P` switch, for example `./gradlew -
 * `testLoggingEvents`: unit test events to be logged, separated by comma. For example `./gradlew -PtestLoggingEvents=started,passed,skipped,failed test`.
 * `xmlSpotBugsReport`: enable XML reports for spotBugs. This also disables HTML reports as only one can be enabled at a time.
 
+### Dependency Analysis ###
+
+The gradle [dependency debugging documentation](https://docs.gradle.org/current/userguide/viewing_debugging_dependencies.html) mentions using the `dependencies` or `dependencyInsight` tasks to debug dependencies for the root project or individual subprojects.
+
+Alternatively, use the `allDeps` or `allDepInsight` tasks for recursively iterating through all subprojects:
+
+    ./gradlew allDeps
+
+    ./gradlew allDepInsight --configuration runtime --dependency com.fasterxml.jackson.core:jackson-databind
+
+These take the same arguments as the builtin variants.
+
 ### Running system tests ###
 
 See [tests/README.md](tests/README.md).

build.gradle

@@ -143,6 +143,14 @@ if (file('.git').exists()) {
 
 
 subprojects {
+
+  // enable running :dependencies task recursively on all subprojects
+  // eg: ./gradlew allDeps
+  task allDeps(type: DependencyReportTask) {}
+  // enable running :dependencyInsight task recursively on all subprojects
+  // eg: ./gradlew allDepInsight --configuration runtime --dependency com.fasterxml.jackson.core:jackson-databind
+  task allDepInsight(type: DependencyInsightReportTask) doLast {}
+
   apply plugin: 'java'
   // apply the eclipse plugin only to subprojects that hold code. 'connect' is just a folder.
   if (!project.name.equals('connect')) {