From 8b13dbcef179975d976729f940451e347ea4f511 Mon Sep 17 00:00:00 2001
From: Kristian Bendiksen <kristian.bendiksen@gmail.com>
Date: Tue, 20 Jan 2026 14:03:49 +0100
Subject: [PATCH] #12940 Fix empty vector parsing and ReadPastEnd handling for
 Python GRPC

- Handle empty arrays [] in std::vector<cvf::Vec3d> parser
- Only treat ReadCorruptData as error in generic template (ReadPastEnd
  is expected for types like caf::FilePath that consume all input)
- Use strict mode (allowExtraCharacters=false) for Python GRPC parsing
---
 .../cafPdmFieldScriptingCapability.h          | 20 ++++---------------
 ...cafPdmFieldScriptingCapabilityCvfVec3d.cpp | 11 +++++++++-
 GrpcInterface/RiaGrpcServiceInterface.cpp     |  2 +-
 3 files changed, 15 insertions(+), 18 deletions(-)

diff --git a/Fwk/AppFwk/cafPdmScripting/cafPdmFieldScriptingCapability.h b/Fwk/AppFwk/cafPdmScripting/cafPdmFieldScriptingCapability.h
index f17c0a07a0..12c0d5b404 100644
--- a/Fwk/AppFwk/cafPdmScripting/cafPdmFieldScriptingCapability.h
+++ b/Fwk/AppFwk/cafPdmScripting/cafPdmFieldScriptingCapability.h
@@ -210,23 +210,11 @@ struct PdmFieldScriptingCapabilityIOHandler
                               bool                 allowExtraCharacters = true )
     {
         inputStream >> fieldValue;
-        if ( inputStream.status() != QTextStream::Ok )
+        // Only report ReadCorruptData as an error. ReadPastEnd just means the stream was fully
+        // consumed, which is expected for types like caf::FilePath that read all available input.
+        if ( inputStream.status() == QTextStream::ReadCorruptData )
         {
-            QString errorMessage;
-            if ( inputStream.status() == QTextStream::ReadPastEnd )
-            {
-                errorMessage = "Read past end of argument";
-            }
-            else if ( inputStream.status() == QTextStream::ReadCorruptData )
-            {
-                errorMessage = "Argument value is unreadable";
-            }
-            else
-            {
-                errorMessage = "Unknown read error";
-            }
-
-            errorMessageContainer->addError( errorMessage + ": \"" + errorMessageContainer->currentArgument +
+            errorMessageContainer->addError( "Argument value is unreadable: \"" + errorMessageContainer->currentArgument +
                                              "\" in the command: \"" + errorMessageContainer->currentCommand + "\"" );
             inputStream.setStatus( QTextStream::Ok );
         }
diff --git a/Fwk/AppFwk/cafPdmScripting/cafPdmFieldScriptingCapabilityCvfVec3d.cpp b/Fwk/AppFwk/cafPdmScripting/cafPdmFieldScriptingCapabilityCvfVec3d.cpp
index d300d53697..d259cf874d 100644
--- a/Fwk/AppFwk/cafPdmScripting/cafPdmFieldScriptingCapabilityCvfVec3d.cpp
+++ b/Fwk/AppFwk/cafPdmScripting/cafPdmFieldScriptingCapabilityCvfVec3d.cpp
@@ -99,6 +99,15 @@ void PdmFieldScriptingCapabilityIOHandler<std::vector<cvf::Vector3<double>>>::wr
     {
         while ( !inputStream.atEnd() )
         {
+            // Check for closing bracket first (handles empty array case)
+            errorMessageContainer->skipWhiteSpaceWithLineNumberCount( inputStream );
+            QChar nextChar = errorMessageContainer->peekNextChar( inputStream );
+            if ( nextChar == QChar( ']' ) )
+            {
+                nextChar = errorMessageContainer->readCharWithLineNumberCount( inputStream );
+                break;
+            }
+
             std::vector<double> fieldVectorValue;
 
             PdmFieldScriptingCapabilityIOHandler<std::vector<double>>::writeToField( fieldVectorValue,
@@ -120,7 +129,7 @@ void PdmFieldScriptingCapabilityIOHandler<std::vector<cvf::Vector3<double>>>::wr
             }
 
             errorMessageContainer->skipWhiteSpaceWithLineNumberCount( inputStream );
-            QChar nextChar = errorMessageContainer->peekNextChar( inputStream );
+            nextChar = errorMessageContainer->peekNextChar( inputStream );
             if ( nextChar == QChar( ']' ) )
             {
                 nextChar = errorMessageContainer->readCharWithLineNumberCount( inputStream );
diff --git a/GrpcInterface/RiaGrpcServiceInterface.cpp b/GrpcInterface/RiaGrpcServiceInterface.cpp
index 58e66245f2..e83a25c33e 100644
--- a/GrpcInterface/RiaGrpcServiceInterface.cpp
+++ b/GrpcInterface/RiaGrpcServiceInterface.cpp
@@ -282,7 +282,7 @@ std::expected<void, QString> RiaGrpcServiceInterface::assignFieldValue( const QS
     // Step 1: Save old value for potential rollback
     if ( valueField ) *oldValue = valueField->toQVariant();
 
-    // Step 2: Parse and set new value
+    // Step 2: Parse and set new value (strict mode for GRPC)
     QTextStream stream( stringValue.toLatin1() );
     scriptability->writeToField( stream, nullptr, messages, false, RimProject::current(), false );