feat: let build.jbang auto-select sources

quintesse · quintesse · commit ed4d92716a5e · 2025-10-11T00:59:25.000+02:00
When no sources are specified, we now look for common source locations.
diff --git a/src/main/java/dev/jbang/resources/ResourceRef.java b/src/main/java/dev/jbang/resources/ResourceRef.java
@@ -6,6 +6,7 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.function.Function;
+import java.util.stream.Stream;
 
 import org.jspecify.annotations.NonNull;
 import org.jspecify.annotations.Nullable;
@@ -65,6 +66,28 @@ static boolean isStdin(@NonNull String scriptResource) {
 		return scriptResource.equals("-") || scriptResource.equals("/dev/stdin");
 	}
 
+	default ResourceRef parent() {
+		throw new ResourceNotFoundException(getOriginalResource(), "Getting parent resource not supported");
+	}
+
+	default boolean isParent() {
+		return false;
+	}
+
+	interface ResourceChildren extends ResourceResolver {
+		Stream<Path> list() throws IOException;
+
+		@Override
+		@Nullable
+		default ResourceRef resolve(String resource) {
+			return resolve(resource, true);
+		}
+	}
+
+	default ResourceChildren children() {
+		throw new ResourceNotFoundException(getOriginalResource(), "Resource is not a parent");
+	}
+
 	/**
 	 * Returns a file representation for this resource reference. If an original
 	 * resource was provided, this method will return a resolved file representation
@@ -77,6 +100,9 @@ static boolean isStdin(@NonNull String scriptResource) {
 	 */
 	@NonNull
 	default Path getFile() {
+		if (isParent()) {
+			throw new ResourceNotFoundException(getOriginalResource(), "Resource is a parent");
+		}
 		throw new ResourceNotFoundException(getOriginalResource(), "Getting contents from resource not supported");
 	}
 
@@ -96,6 +122,9 @@ default Path getFile() {
 	 * @return an InputStream for the resource, or null if no file is associated
 	 */
 	default InputStream getInputStream() {
+		if (isParent()) {
+			throw new ResourceNotFoundException(getOriginalResource(), "Resource is a parent");
+		}
 		try {
 			return Files.newInputStream(getFile());
 		} catch (IOException e) {
diff --git a/src/main/java/dev/jbang/resources/resolvers/FileResourceResolver.java b/src/main/java/dev/jbang/resources/resolvers/FileResourceResolver.java
@@ -1,12 +1,15 @@
 package dev.jbang.resources.resolvers;
 
+import java.io.IOException;
+import java.nio.file.FileVisitOption;
 import java.nio.file.Files;
 import java.nio.file.InvalidPathException;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.function.Function;
+import java.util.stream.Stream;
 
 import org.jspecify.annotations.NonNull;
 import org.jspecify.annotations.Nullable;
@@ -81,7 +84,7 @@ public String getOriginalResource() {
 		@Override
 		public boolean exists() {
 			try {
-				return Files.isRegularFile(getFile());
+				return Files.exists(getFile());
 			} catch (ResourceNotFoundException e) {
 				return false;
 			}
@@ -96,6 +99,9 @@ public Path getFile() {
 			if (!file.isPresent()) {
 				throw new ResourceNotFoundException(getOriginalResource(), "Could not obtain file resource");
 			}
+			if (isParent()) {
+				throw new ResourceNotFoundException(getOriginalResource(), "Resource is a parent");
+			}
 			return file.get();
 		}
 
@@ -109,6 +115,51 @@ public String getExtension() {
 			}
 		}
 
+		@Override
+		public ResourceRef parent() {
+			Path parentPath = Paths.get(originalResource).getParent();
+			return new FileResourceRef(parentPath.toString(), parentPath, resolver);
+		}
+
+		@Override
+		public boolean isParent() {
+			if (file == null) {
+				file = Optional.ofNullable(obtainer.apply(getOriginalResource()));
+			}
+			return file.isPresent() && Files.isDirectory(file.get());
+		}
+
+		@Override
+		public ResourceChildren children() {
+			if (!isParent()) {
+				throw new ResourceNotFoundException(getOriginalResource(), "Resource is not a parent");
+			}
+			return new ResourceChildren() {
+				@Override
+				public Stream<Path> list() throws IOException {
+					if (file == null) {
+						file = Optional.ofNullable(obtainer.apply(getOriginalResource()));
+					}
+					return file.isPresent() ? Files.walk(file.get(), FileVisitOption.FOLLOW_LINKS) : Stream.empty();
+				}
+
+				@Override
+				public @Nullable ResourceRef resolve(String resource, boolean trusted) {
+					if (!Util.isValidPath(resource)) {
+						return null;
+					}
+					Path baseDir = Paths.get(originalResource);
+					String childRef = baseDir.resolve(resource).toString();
+					return resolver.resolve(childRef, trusted);
+				}
+
+				@Override
+				public @NonNull String description() {
+					return "Children of " + FileResourceRef.this.description();
+				}
+			};
+		}
+
 		@Override
 		public @Nullable ResourceRef resolve(String resource, boolean trusted) {
 			if (!Util.isValidPath(resource)) {
diff --git a/src/main/java/dev/jbang/resources/resolvers/RenamingScriptResourceResolver.java b/src/main/java/dev/jbang/resources/resolvers/RenamingScriptResourceResolver.java
@@ -1,5 +1,7 @@
 package dev.jbang.resources.resolvers;
 
+import static dev.jbang.util.Util.MAIN_JAVA;
+
 import java.io.File;
 import java.io.IOException;
 import java.nio.file.InvalidPathException;
@@ -59,7 +61,7 @@ public ResourceRef resolve(String resource) {
 						&& !knownExtensions.contains(ext)
 						&& (!Util.isPreview() || !Project.BuildFile.fileNames().contains(probe.getName()))) {
 					if (probe.isDirectory()) {
-						File defaultApp = new File(probe, "main.java");
+						File defaultApp = new File(probe, MAIN_JAVA);
 						File buildFile = new File(probe, Project.BuildFile.jbang.fileName);
 						if (Util.isPreview() && buildFile.exists()) {
 							Util.verboseMsg("Directory where build.jbang exists. Running build.jbang.");
diff --git a/src/main/java/dev/jbang/source/ProjectBuilder.java b/src/main/java/dev/jbang/source/ProjectBuilder.java
@@ -1,5 +1,7 @@
 package dev.jbang.source;
 
+import static dev.jbang.util.Util.MAIN_JAVA;
+
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
@@ -366,7 +368,24 @@ private Project createJbangProject(ResourceRef resourceRef) {
 		}
 
 		boolean first = true;
-		List<Source> includedSources = allToSource(directives.sources(), resourceRef, sibRes2);
+		List<String> sources = directives.sources();
+		if (sources.isEmpty()) {
+			// if no sources are defined, we go look for a couple of possible options
+			if (resourceRef.resolve(MAIN_JAVA) != null) {
+				sources.add(MAIN_JAVA);
+			} else {
+				if (resourceRef.resolve("src/main/java") != null) {
+					sources.add("src/main/java/**.java");
+				}
+				if (resourceRef.resolve("src/main/kotlin") != null) {
+					sources.add("src/main/kotlin/**.kt");
+				}
+				if (resourceRef.resolve("src/main/groovy") != null) {
+					sources.add("src/main/groovy/**.groovy");
+				}
+			}
+		}
+		List<Source> includedSources = allToSource(sources, resourceRef, sibRes2);
 		for (Source includedSource : includedSources) {
 			updateProject(includedSource, prj, resolver);
 			if (first) {
diff --git a/src/main/java/dev/jbang/util/Util.java b/src/main/java/dev/jbang/util/Util.java
@@ -96,6 +96,8 @@ public class Util {
 	private static final Pattern subUrlPattern = Pattern.compile(
 			"^(%?%https?://.+$)|(%?%\\{[a-z]+:[^}]+})");
 
+	public static final String MAIN_JAVA = "main.java";
+
 	private static boolean verbose;
 	private static boolean quiet;
 	private static boolean offline;
@@ -1297,7 +1299,7 @@ public static String swizzleURL(String url) {
 				URI u = new URI(url);
 				if (u.getPath().endsWith("/")) {
 					verboseMsg("Directory url, assuming user want to get default application at main.java");
-					url = url + "main.java";
+					url = url + MAIN_JAVA;
 				}
 			} catch (URISyntaxException e) {
 				// ignore
diff --git a/src/test/java/dev/jbang/source/TestProjectBuilder.java b/src/test/java/dev/jbang/source/TestProjectBuilder.java
@@ -1,10 +1,12 @@
 package dev.jbang.source;
 
+import static dev.jbang.util.Util.MAIN_JAVA;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.aMapWithSize;
 import static org.hamcrest.Matchers.anEmptyMap;
 import static org.hamcrest.Matchers.contains;
 import static org.hamcrest.Matchers.containsInAnyOrder;
+import static org.hamcrest.Matchers.endsWith;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.hasEntry;
 import static org.hamcrest.Matchers.instanceOf;
@@ -13,13 +15,15 @@
 import static org.hamcrest.Matchers.nullValue;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import java.io.File;
 import java.io.IOException;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.Arrays;
 import java.util.stream.Collectors;
 
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
 
 import dev.jbang.BaseTest;
 import dev.jbang.cli.ExitException;
@@ -346,4 +350,43 @@ void testMissingFilesTags() {
 			.filter(rt -> rt.getSource() instanceof ResourceRef.UnresolvableResourceRef)
 			.collect(Collectors.toList()), iterableWithSize(2));
 	}
+
+	@Test
+	void testBuildJbangAutoSourcesMainJava(@TempDir Path tmpDir) throws IOException {
+		Util.setPreview(true);
+
+		Path src = tmpDir.resolve("build.jbang");
+		Util.writeString(src, "//DESCRIPTION Test\n");
+		Util.writeString(tmpDir.resolve(MAIN_JAVA), "//Dummy source file");
+
+		ProjectBuilder pb = Project.builder();
+		Project prj = pb.build(src);
+		assertThat(prj.getMainSourceSet().getSources(), iterableWithSize(1));
+		assertThat(prj.getMainSourceSet().getSources().get(0).getFile().toString(),
+				endsWith(File.separator + MAIN_JAVA));
+		assertThat(prj.getMainSourceSet().getSources(), containsInAnyOrder(
+				ResourceRef.forFile(tmpDir.resolve(MAIN_JAVA))));
+	}
+
+	@Test
+	void testBuildJbangAutoSourcesDirs(@TempDir Path tmpDir) throws IOException {
+		Util.setPreview(true);
+
+		Path src = tmpDir.resolve("build.jbang");
+		Util.writeString(src, "//DESCRIPTION Test\n");
+		Path dirs = tmpDir.resolve("src/main/java");
+		dirs.toFile().mkdirs();
+		Util.writeString(dirs.resolve("Foo.java"), "//Dummy source file");
+		Util.writeString(dirs.resolve("Bar.java"), "//Dummy source file");
+		dirs.resolve("baz").toFile().mkdirs();
+		Util.writeString(dirs.resolve("baz/Baz.java"), "//Dummy source file");
+
+		ProjectBuilder pb = Project.builder();
+		Project prj = pb.build(src);
+		assertThat(prj.getMainSourceSet().getSources(), iterableWithSize(3));
+		assertThat(prj.getMainSourceSet().getSources(), containsInAnyOrder(
+				ResourceRef.forFile(dirs.resolve("Foo.java")),
+				ResourceRef.forFile(dirs.resolve("Bar.java")),
+				ResourceRef.forFile(dirs.resolve("baz/Baz.java"))));
+	}
 }
