Merge pull request #71782 from ahoppen/ahoppen/incomplete-output-file-map

[Driver] Don’t crash if the output file map is incomplete

Author: ahoppen

lib/Basic/OutputFileMap.cpp

@@ -209,6 +209,12 @@ OutputFileMap::parse(std::unique_ptr<llvm::MemoryBuffer> Buffer,
       llvm::yaml::Node *Key = OutputPair.getKey();
       llvm::yaml::Node *Value = OutputPair.getValue();
 
+      if (!Key)
+        return constructError("bad kind");
+
+      if (!Value)
+        return constructError("bad path");
+
       auto *KindNode = dyn_cast<llvm::yaml::ScalarNode>(Key);
       if (!KindNode)
         return constructError("kind not a ScalarNode");

test/Driver/malformed-ofm.swift

@@ -0,0 +1,14 @@
+// Ensure that an incomplete output-file-map path does not crash the driver,
+// but instead outputs a nice diagnostic.
+//
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: not %swiftc_driver -c %S/../Inputs/empty.swift -output-file-map %t/malformed-output-file-map.json 2>&1 | %FileCheck %s
+//
+// CHECK: error: Expected quote at end of scalar
+// CHECK-NOT: Assertion failed
+
+//--- malformed-output-file-map.json
+{
+  "/path/to/some/file.swift": {
+    "dependencies": "