[flang][runtime] Handle incomplete NAMELIST input derived type compon… (#66831)

…ent list

When a derived type value appears in NAMELIST input, its components'
values appear in sequence. This sequence can be truncated by a NAME=
that begins the next NAMELIST input item, or by the terminal '/' that
ends the NAMELIST group. Extend the mechanism already in place for
truncated array item lists in NAMELIST input so that it also applies to
derived type component sequences, and rename things appropriately.

Author: klausler

flang/runtime/descriptor-io.h

@@ -288,7 +288,11 @@ static bool DefaultComponentwiseIO(IoStatementState &io,
           *compArray.Element<typeInfo::Component>(at)};
       if (!DefaultComponentIO<DIR>(
               io, component, descriptor, subscripts, handler, table)) {
-        return false;
+        // Truncated nonempty namelist input sequence?
+        auto *listInput{
+            io.get_if<ListDirectedStatementState<Direction::Input>>()};
+        return DIR == Direction::Input && (j > 0 || k > 0) && listInput &&
+            listInput->inNamelistSequence();
       }
     }
   }

flang/runtime/io-stmt.h

@@ -295,8 +295,7 @@ template <>
 class ListDirectedStatementState<Direction::Input>
     : public FormattedIoStatementState<Direction::Input> {
 public:
-  bool inNamelistArray() const { return inNamelistArray_; }
-  void set_inNamelistArray(bool yes = true) { inNamelistArray_ = yes; }
+  bool inNamelistSequence() const { return inNamelistSequence_; }
 
   // Skips value separators, handles repetition and null values.
   // Vacant when '/' appears; present with descriptor == ListDirectedNullValue
@@ -308,11 +307,11 @@ class ListDirectedStatementState<Direction::Input>
   // input statement.  This member function resets some state so that
   // repetition and null values work correctly for each successive
   // NAMELIST input item.
-  void ResetForNextNamelistItem(bool inNamelistArray) {
+  void ResetForNextNamelistItem(bool inNamelistSequence) {
     remaining_ = 0;
     eatComma_ = false;
     realPart_ = imaginaryPart_ = false;
-    inNamelistArray_ = inNamelistArray;
+    inNamelistSequence_ = inNamelistSequence;
   }
 
 private:
@@ -322,7 +321,7 @@ class ListDirectedStatementState<Direction::Input>
   bool hitSlash_{false}; // once '/' is seen, nullify further items
   bool realPart_{false};
   bool imaginaryPart_{false};
-  bool inNamelistArray_{false};
+  bool inNamelistSequence_{false};
 };
 
 template <Direction DIR>

flang/runtime/namelist.cpp

@@ -522,15 +522,18 @@ bool IONAME(InputNamelist)(Cookie cookie, const NamelistGroup &group) {
     }
     io.HandleRelativePosition(byteCount);
     // Read the values into the descriptor.  An array can be short.
-    listInput->ResetForNextNamelistItem(useDescriptor->rank() > 0);
     if (const auto *addendum{useDescriptor->Addendum()};
         addendum && addendum->derivedType()) {
       const NonTbpDefinedIoTable *table{group.nonTbpDefinedIo};
+      listInput->ResetForNextNamelistItem(/*inNamelistSequence=*/true);
       if (!IONAME(InputDerivedType)(cookie, *useDescriptor, table)) {
         return false;
       }
-    } else if (!descr::DescriptorIO<Direction::Input>(io, *useDescriptor)) {
-      return false;
+    } else {
+      listInput->ResetForNextNamelistItem(useDescriptor->rank() > 0);
+      if (!descr::DescriptorIO<Direction::Input>(io, *useDescriptor)) {
+        return false;
+      }
     }
     next = io.GetNextNonBlank(byteCount);
     if (next && *next == comma) {
@@ -549,7 +552,7 @@ bool IONAME(InputNamelist)(Cookie cookie, const NamelistGroup &group) {
 bool IsNamelistNameOrSlash(IoStatementState &io) {
   if (auto *listInput{
           io.get_if<ListDirectedStatementState<Direction::Input>>()}) {
-    if (listInput->inNamelistArray()) {
+    if (listInput->inNamelistSequence()) {
       SavedPosition savedPosition{io};
       std::size_t byteCount{0};
       if (auto ch{io.GetNextNonBlank(byteCount)}) {