Fix Tomcat TldScanner issues by returning raw zip data for nested jars

Update JarUrlConnection so that the full raw zip data is returned from
nested jars when no entry name is specified. This update allows
Tomcat's `WarURLConnection` to work with our nested connections since
they can parse the returned raw zip data.

Fixes gh-38047

spring-boot-project/spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/jar/NestedJarFile.java

@@ -17,6 +17,7 @@
 package org.springframework.boot.loader.jar;
 
 import java.io.File;
+import java.io.FilterInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.UncheckedIOException;
@@ -143,6 +144,13 @@ public class NestedJarFile extends JarFile {
 		this.version = (version != null) ? version.feature() : baseVersion().feature();
 	}
 
+	public InputStream getRawZipDataInputStream() throws IOException {
+		RawZipDataInputStream inputStream = new RawZipDataInputStream(
+				this.resources.zipContent().openRawZipData().asInputStream());
+		this.resources.addInputStream(inputStream);
+		return inputStream;
+	}
+
 	@Override
 	public Manifest getManifest() throws IOException {
 		try {
@@ -799,4 +807,27 @@ public class NestedJarFile extends JarFile {
 
 	}
 
+	/**
+	 * {@link InputStream} for raw zip data.
+	 */
+	private class RawZipDataInputStream extends FilterInputStream {
+
+		private volatile boolean closed;
+
+		protected RawZipDataInputStream(InputStream in) {
+			super(in);
+		}
+
+		@Override
+		public void close() throws IOException {
+			if (this.closed) {
+				return;
+			}
+			this.closed = true;
+			super.close();
+			NestedJarFile.this.resources.removeInputStream(this);
+		}
+
+	}
+
 }

spring-boot-project/spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/net/protocol/jar/JarUrlConnection.java

@@ -175,11 +175,12 @@ final class JarUrlConnection extends java.net.JarURLConnection {
 		if (this.notFound != null) {
 			throwFileNotFound();
 		}
-		if (this.entryName == null) {
+		URL jarFileURL = getJarFileURL();
+		if (this.entryName == null && !UrlJarFileFactory.isNestedUrl(jarFileURL)) {
 			throw new IOException("no entry name specified");
 		}
-		if (!getUseCaches() && Optimizations.isEnabled(false)) {
-			JarFile cached = jarFiles.getCached(getJarFileURL());
+		if (!getUseCaches() && Optimizations.isEnabled(false) && this.entryName != null) {
+			JarFile cached = jarFiles.getCached(jarFileURL);
 			if (cached != null) {
 				if (cached.getEntry(this.entryName) != null) {
 					return emptyInputStream;
@@ -188,6 +189,12 @@ final class JarUrlConnection extends java.net.JarURLConnection {
 		}
 		connect();
 		if (this.jarEntry == null) {
+			if (this.jarFile instanceof NestedJarFile nestedJarFile) {
+				// In order to work with Tomcat's TLD scanning and WarURLConnection we
+				// return the raw zip data rather than failing because there is no entry.
+				// See gh-38047 for details.
+				return nestedJarFile.getRawZipDataInputStream();
+			}
 			throwFileNotFound();
 		}
 		return new ConnectionInputStream();

spring-boot-project/spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/net/protocol/jar/UrlJarFileFactory.java

@@ -80,10 +80,6 @@ class UrlJarFileFactory {
 		return new UrlJarFile(new File(path), version, closeAction);
 	}
 
-	private boolean isNestedUrl(URL url) {
-		return url.getProtocol().equalsIgnoreCase("nested");
-	}
-
 	private JarFile createJarFileForNested(URL url, Runtime.Version version, Consumer<JarFile> closeAction)
 			throws IOException {
 		NestedLocation location = NestedLocation.fromUrl(url);
@@ -120,4 +116,8 @@ class UrlJarFileFactory {
 		}
 	}
 
+	static boolean isNestedUrl(URL url) {
+		return url.getProtocol().equalsIgnoreCase("nested");
+	}
+
 }

spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/net/protocol/jar/JarUrlConnectionTests.java

@@ -22,6 +22,7 @@ import java.io.FileOutputStream;
 import java.io.FilterInputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.OutputStream;
 import java.net.URL;
 import java.net.URLConnection;
 import java.nio.charset.StandardCharsets;
@@ -237,8 +238,8 @@ class JarUrlConnectionTests {
 	}
 
 	@Test
-	void getInputStreamWhenHasNoEntryThrowsException() throws Exception {
-		JarUrlConnection connection = JarUrlConnection.open(this.url);
+	void getInputStreamWhenNotNestedAndHasNoEntryThrowsException() throws Exception {
+		JarUrlConnection connection = JarUrlConnection.open(JarUrl.create(this.file));
 		assertThatIOException().isThrownBy(() -> connection.getInputStream()).withMessage("no entry name specified");
 	}
 
@@ -271,6 +272,18 @@ class JarUrlConnectionTests {
 			.withMessageContaining("JAR entry missing.dat not found in");
 	}
 
+	@Test // gh-38047
+	void getInputStreamWhenNoEntryAndNestedReturnsFullJarInputStream() throws Exception {
+		JarUrlConnection connection = JarUrlConnection.open(JarUrl.create(this.file, "nested.jar"));
+		File outFile = new File(this.temp, "out.zip");
+		try (OutputStream out = new FileOutputStream(outFile)) {
+			connection.getInputStream().transferTo(out);
+		}
+		try (JarFile outJar = new JarFile(outFile)) {
+			assertThat(outJar.getEntry("3.dat")).isNotNull();
+		}
+	}
+
 	@Test
 	void getInputStreamReturnsInputStream() throws IOException {
 		JarUrlConnection connection = JarUrlConnection.open(JarUrl.create(this.file, "nested.jar", "3.dat"));