fix: Fixes dependent source discovery

Parent directories for sources are now added to the compiler's source
path so any types referenced in them that are available in the same
directories can be found even when they are not explicitely mentioned
in any `//SOURCES` lines. This also fixes the problem where adding a
`//DEPS` line would cause the compiler to be unable to find those same
types.

Fixes jbangdev#1502

itests/extending/Bar.java

@@ -0,0 +1,3 @@
+package extending;
+
+public class Bar {}

itests/extending/Foo.java

@@ -0,0 +1,10 @@
+///usr/bin/env jbang "$0" "$@" ; exit $?
+///DEPS com.github.lalyos:jfiglet:0.0.9
+
+package extending;
+
+public class Foo extends Bar {
+    public static void main(String... args) {
+        System.out.println("hello JBang");
+    }
+}

src/main/java/dev/jbang/dependencies/ModularClassPath.java

@@ -50,12 +50,16 @@ public List<String> getClassPaths() {
 
 	public String getClassPath() {
 		if (classPath == null) {
-			classPath = String.join(CP_SEPARATOR, getClassPaths());
+			classPath = toClassPath(getClassPaths());
 		}
 
 		return classPath;
 	}
 
+	public static String toClassPath(List<String> pathElements) {
+		return String.join(CP_SEPARATOR, pathElements);
+	}
+
 	public String getManifestPath() {
 		if (manifestPath == null) {
 			manifestPath = artifacts.stream()

src/main/java/dev/jbang/source/buildsteps/CompileBuildStep.java

@@ -10,6 +10,7 @@
 
 import dev.jbang.cli.ExitException;
 import dev.jbang.dependencies.MavenCoordinate;
+import dev.jbang.dependencies.ModularClassPath;
 import dev.jbang.source.Builder;
 import dev.jbang.source.Project;
 import dev.jbang.util.CommandBuffer;
@@ -42,10 +43,24 @@ protected Project compile() throws IOException {
 		optionList.addAll(project.getMainSourceSet().getCompileOptions());
 		String path = project.resolveClassPath().getClassPath();
 		if (!Util.isBlankString(path)) {
-			optionList.addAll(Arrays.asList("-classpath", path));
+			optionList.add("-classpath");
+			optionList.add(path);
 		}
 		optionList.addAll(Arrays.asList("-d", compileDir.toAbsolutePath().toString()));
 
+		// add -sourcepath for all source folders
+		List<String> srcDirs = project	.getMainSourceSet()
+										.getSources()
+										.stream()
+										.map(x -> x.getFile().getParent().toAbsolutePath())
+										.distinct()
+										.map(Path::toString)
+										.collect(Collectors.toList());
+		if (!srcDirs.isEmpty()) {
+			optionList.add("-sourcepath");
+			optionList.add(ModularClassPath.toClassPath(srcDirs));
+		}
+
 		// add source files to compile
 		optionList.addAll(project	.getMainSourceSet()
 									.getSources()

src/main/java/dev/jbang/source/generators/JshCmdGenerator.java

@@ -12,6 +12,7 @@
 
 import org.apache.commons.text.StringEscapeUtils;
 
+import dev.jbang.dependencies.ModularClassPath;
 import dev.jbang.source.*;
 import dev.jbang.util.JavaUtil;
 import dev.jbang.util.Util;
@@ -98,6 +99,19 @@ protected List<String> generateCommandLineList() throws IOException {
 		fullArgs.addAll(optionalArgs);
 
 		if (project.isJShell()) {
+			// add -sourcepath for all source folders
+			List<String> srcDirs = project	.getMainSourceSet()
+											.getSources()
+											.stream()
+											.map(x -> x.getFile().getParent().toAbsolutePath())
+											.distinct()
+											.map(Path::toString)
+											.collect(Collectors.toList());
+			if (!srcDirs.isEmpty()) {
+				fullArgs.add("-C-sourcepath");
+				fullArgs.add(ModularClassPath.toClassPath(srcDirs));
+			}
+
 			ArrayList<ResourceRef> revSources = new ArrayList<>(project.getMainSourceSet().getSources());
 			Collections.reverse(revSources);
 			for (ResourceRef s : revSources) {

src/test/java/dev/jbang/source/TestBuilder.java

@@ -204,6 +204,7 @@ void testAdditionalSourcesFolder() throws IOException {
 		Util.setCwd(examplesTestFolder);
 		String mainFile = examplesTestFolder.resolve("foo.java").toString();
 		String incFile = examplesTestFolder.resolve("bar/Bar.java").toString();
+		String srcPath = examplesTestFolder + File.pathSeparator + examplesTestFolder.resolve("bar");
 
 		ProjectBuilder pb = ProjectBuilder.create();
 		pb.additionalSources(Arrays.asList("bar"));
@@ -217,6 +218,7 @@ protected Builder<Project> getCompileBuildStep() {
 					protected void runCompiler(List<String> optionList) {
 						assertThat(optionList, hasItem(mainFile));
 						assertThat(optionList, hasItem(incFile));
+						assertThat(optionList, hasItems("-sourcepath", srcPath));
 						// Skip the compiler
 					}
 				};
@@ -490,4 +492,25 @@ protected void runNativeBuilder(List<String> optionList) throws IOException {
 			}
 		}.setFresh(true).build();
 	}
+
+	@Test
+	void testMultiSourceWithDeps() throws IOException {
+		Path fooDir = examplesTestFolder.resolve("extending").toAbsolutePath();
+		Path foo = fooDir.resolve("Foo.java");
+		ProjectBuilder pb = ProjectBuilder.create();
+		Project prj = pb.build(foo.toString());
+
+		new JavaSource.JavaAppBuilder(prj) {
+			@Override
+			protected Builder<Project> getCompileBuildStep() {
+				return new JavaCompileBuildStep() {
+					@Override
+					protected void runCompiler(List<String> optionList) {
+						assertThat(optionList, hasItems("-sourcepath", fooDir.toString(), foo.toString()));
+						// Skip the compiler
+					}
+				};
+			}
+		}.setFresh(true).build();
+	}
 }