Merge pull request #588 from diffplug/feat/outside-project-dir

Better error message if you try to format a file outside the project directory.

Author: nedtwigg

plugin-gradle/CHANGES.md

@@ -9,6 +9,7 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 * Users can now run `spotlessCheck` and `spotlessApply` in the same build. ([#584](https://github.com/diffplug/spotless/pull/584))
 * Fixed intermittent `UnsatisfiedLinkError` in nodejs-based steps. ([#586](https://github.com/diffplug/spotless/pull/586))
   * Also, a shared library used by the nodejs steps used to be extracted into the user home directory, but now it is extracted into `{rootProject}/build/spotless-nodejs-cache`.
+* Starting in `4.0`, it is no longer possible for a project to format files which are not within its project folder (for example, `:a` can no longer format files in `:b`).  We did not explicitly note this in the changelog entry for `4.0`, and we gave a very confusing error message if users tried.  We now give a more helpful error message, and this breaking change has been retroactively noted in the changelog for `4.0.0`. ([#588](https://github.com/diffplug/spotless/pull/588))
 
 ## [4.0.1] - 2020-05-21
 ### Fixed
@@ -21,6 +22,7 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 * Support for the gradle build cache. ([#576](https://github.com/diffplug/spotless/pull/576))
   * The local cache will work great, but the remote cache will always miss until [#566](https://github.com/diffplug/spotless/issues/566) is resolved.
 ### Removed
+* **BREAKING** it used to be possible for any project to format files in any other project.  For example, `:a` could format files in `:b`.  It is now only possible to format files within the project directory.  It is okay (but not advised) to format files in subprojects, since they are within the project directory.
 * (Power users only) **BREAKING** `void SpotlessTask::setCheck()` and `setApply()` have been removed. ([#576](https://github.com/diffplug/spotless/pull/576))
   * Previously, the `check` and `apply` tasks were just marker tasks, and they called `setCheck` and `setApply` on the "worker" task.  Now `check` and `apply` are real tasks in their own right, so the marker-task kludge is no longer necessary.
 ### Changed

plugin-gradle/src/main/java/com/diffplug/gradle/spotless/SpotlessTask.java

@@ -44,6 +44,7 @@
 import org.gradle.api.tasks.incremental.IncrementalTaskInputs;
 
 import com.diffplug.common.base.Errors;
+import com.diffplug.common.base.StringPrinter;
 import com.diffplug.spotless.FormatExceptionPolicy;
 import com.diffplug.spotless.FormatExceptionPolicyStrict;
 import com.diffplug.spotless.Formatter;
@@ -245,7 +246,11 @@ private void deletePreviousResult(File input) throws IOException {
 	private File getOutputFile(File input) {
 		String outputFileName = FormatExtension.relativize(getProject().getProjectDir(), input);
 		if (outputFileName == null) {
-			outputFileName = input.getAbsolutePath();
+			throw new IllegalArgumentException(StringPrinter.buildString(printer -> {
+				printer.println("Spotless error! All target files must be within the project root. In project " + getProject().getPath());
+				printer.println("  root dir: " + getProject().getProjectDir().getAbsolutePath());
+				printer.println("    target: " + input.getAbsolutePath());
+			}));
 		}
 		return new File(outputDirectory, outputFileName);
 	}