core: skip finally extract visitor on error

jadx-core/src/main/java/jadx/core/dex/visitors/DepthTraversal.java

@@ -34,4 +34,7 @@ public class DepthTraversal {
 					e.getClass().getSimpleName() + " in pass: " + visitor.getClass().getSimpleName(), e);
 		}
 	}
+
+	private DepthTraversal() {
+	}
 }

jadx-core/src/main/java/jadx/core/dex/visitors/blocksmaker/BlockFinallyExtract.java

 package jadx.core.dex.visitors.blocksmaker;
 
+import java.util.ArrayList;
+import java.util.BitSet;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import jadx.core.Jadx;
 import jadx.core.dex.attributes.AFlag;
 import jadx.core.dex.attributes.AType;
 import jadx.core.dex.attributes.nodes.IgnoreEdgeAttr;
@@ -14,26 +29,15 @@ import jadx.core.dex.trycatch.ExceptionHandler;
 import jadx.core.dex.trycatch.SplitterBlockAttr;
 import jadx.core.dex.trycatch.TryCatchBlock;
 import jadx.core.dex.visitors.AbstractVisitor;
+import jadx.core.dex.visitors.DepthTraversal;
+import jadx.core.dex.visitors.IDexTreeVisitor;
 import jadx.core.dex.visitors.blocksmaker.helpers.BlocksPair;
 import jadx.core.dex.visitors.blocksmaker.helpers.BlocksRemoveInfo;
 import jadx.core.dex.visitors.ssa.LiveVarAnalysis;
 import jadx.core.utils.BlockUtils;
+import jadx.core.utils.ErrorsCounter;
 import jadx.core.utils.exceptions.JadxRuntimeException;
 
-import java.util.ArrayList;
-import java.util.BitSet;
-import java.util.HashSet;
-import java.util.Iterator;
-import java.util.LinkedList;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
-
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
 import static jadx.core.dex.visitors.blocksmaker.BlockSplitter.connect;
 import static jadx.core.dex.visitors.blocksmaker.BlockSplitter.insertBlockBetween;
 import static jadx.core.dex.visitors.blocksmaker.BlockSplitter.removeConnection;
@@ -46,16 +50,34 @@ public class BlockFinallyExtract extends AbstractVisitor {
 		if (mth.isNoCode() || mth.isNoExceptionHandlers()) {
 			return;
 		}
-
-		boolean reloadBlocks = false;
-		for (ExceptionHandler excHandler : mth.getExceptionHandlers()) {
-			if (processExceptionHandler(mth, excHandler)) {
-				reloadBlocks = true;
+		try {
+			boolean reloadBlocks = false;
+			for (ExceptionHandler excHandler : mth.getExceptionHandlers()) {
+				if (processExceptionHandler(mth, excHandler)) {
+					reloadBlocks = true;
+				}
+			}
+			if (reloadBlocks) {
+				mergeReturnBlocks(mth);
+				BlockProcessor.rerun(mth);
+			}
+		} catch (Exception e) {
+			LOG.warn("Undo finally extract visitor, mth: {}", mth, e);
+			try {
+				// reload method without applying this visitor
+				// TODO: make more common and less hacky
+				mth.unload();
+				mth.load();
+				List<IDexTreeVisitor> passes = Jadx.getPassesList(mth.root().getArgs());
+				for (IDexTreeVisitor visitor : passes) {
+					if (visitor instanceof BlockFinallyExtract) {
+						break;
+					}
+					DepthTraversal.visit(visitor, mth);
+				}
+			} catch (Exception ee) {
+				LOG.error("Undo finally extract failed, mth: {}", mth, e);
 			}
-		}
-		if (reloadBlocks) {
-			mergeReturnBlocks(mth);
-			BlockProcessor.rerun(mth);
 		}
 	}
 
@@ -221,7 +243,7 @@ public class BlockFinallyExtract extends AbstractVisitor {
 	}
 
 	private static void performVariablesReMap(MethodNode mth, List<BlocksRemoveInfo> removes,
-			LiveVarAnalysis laBefore, LiveVarAnalysis laAfter) {
+	                                          LiveVarAnalysis laBefore, LiveVarAnalysis laAfter) {
 		BitSet processed = new BitSet(mth.getRegsCount());
 		for (BlocksRemoveInfo removeInfo : removes) {
 			processed.clear();
@@ -390,7 +412,7 @@ public class BlockFinallyExtract extends AbstractVisitor {
 	}
 
 	private static boolean checkInsns(List<InsnNode> remInsns, List<InsnNode> startInsns, int delta,
-			@Nullable BlocksRemoveInfo removeInfo) {
+	                                  @Nullable BlocksRemoveInfo removeInfo) {
 		for (int i = startInsns.size() - 1; i >= 0; i--) {
 			InsnNode startInsn = startInsns.get(i);
 			InsnNode remInsn = remInsns.get(delta + i);
@@ -402,7 +424,7 @@ public class BlockFinallyExtract extends AbstractVisitor {
 	}
 
 	private static boolean checkBlocksTree(BlockNode remBlock, BlockNode startBlock,
-			@NotNull BlocksRemoveInfo removeInfo, BitSet bs) {
+	                                       @NotNull BlocksRemoveInfo removeInfo, BitSet bs) {
 		// skip check on start block
 		if (!removeInfo.getProcessed().isEmpty()
 				&& !sameBlocks(remBlock, startBlock, removeInfo)) {
@@ -436,7 +458,7 @@ public class BlockFinallyExtract extends AbstractVisitor {
 	}
 
 	private static boolean sameBlocks(BlockNode remBlock, BlockNode finallyBlock,
-			@NotNull BlocksRemoveInfo removeInfo) {
+	                                  @NotNull BlocksRemoveInfo removeInfo) {
 		List<InsnNode> first = remBlock.getInstructions();
 		List<InsnNode> second = finallyBlock.getInstructions();
 		if (first.size() < second.size()) {
@@ -495,6 +517,12 @@ public class BlockFinallyExtract extends AbstractVisitor {
 			LOG.warn("Finally extract failed: remBlock pred: {}, {}, method: {}", remBlock, remBlock.getPredecessors(), mth);
 			return false;
 		}
+		if (removeInfo.getOuts().isEmpty()) {
+			ErrorsCounter.methodError(mth, "Failed to extract finally block: empty outs");
+			return false;
+		}
+		// safe checks finished, altering blocks tree
+		// all error must throw exception to undo changes
 
 		BlockNode remBlockPred = remBlock.getPredecessors().get(0);
 		removeInfo.setStartPredecessor(remBlockPred);
@@ -534,7 +562,11 @@ public class BlockFinallyExtract extends AbstractVisitor {
 			}
 		}
 
-		BlocksPair out = removeInfo.getOuts().iterator().next();
+		Set<BlocksPair> outs = removeInfo.getOuts();
+		if (outs.isEmpty()) {
+			throw new JadxRuntimeException("Failed to extract finally block: all outs is deleted");
+		}
+		BlocksPair out = outs.iterator().next();
 		BlockNode rOut = out.getFirst();
 		BlockNode sOut = out.getSecond();
 
@@ -556,8 +588,7 @@ public class BlockFinallyExtract extends AbstractVisitor {
 			BlockNode pred = filtPreds.get(0);
 			BlockNode repl = removeInfo.getBySecond(pred);
 			if (repl == null) {
-				LOG.error("Block not found by {}, in {}, method: {}", pred, removeInfo, mth);
-				return false;
+				throw new JadxRuntimeException("Block not found by " + pred + ", in " + removeInfo);
 			}
 			removeConnection(pred, rOut);
 			addIgnoredEdge(repl, rOut);