From 5e7cc30564ec261260bddcfd68b82fce7d5827a9 Mon Sep 17 00:00:00 2001
From: Jeff Young <jeff@rokeby.ie>
Date: Fri, 24 Feb 2023 00:37:00 +0000
Subject: [PATCH] Don't mess up user formatting if eval'ing didn't actually
 change value.

Fixes https://gitlab.com/kicad/code/kicad/issues/13989

(cherry picked from commit 8059edff0eb36a7d4263255a66b8f2cb45b8ebad)
---
 eeschema/sim/sim_model.cpp    |  5 ++++-
 eeschema/sim/sim_property.cpp | 20 ++++++++++++++------
 eeschema/sim/sim_value.cpp    | 13 +++++++++++++
 eeschema/sim/sim_value.h      |  6 +-----
 4 files changed, 32 insertions(+), 12 deletions(-)

diff --git a/eeschema/sim/sim_model.cpp b/eeschema/sim/sim_model.cpp
index 74686286ac..9332d71a17 100644
--- a/eeschema/sim/sim_model.cpp
+++ b/eeschema/sim/sim_model.cpp
@@ -859,7 +859,10 @@ void SIM_MODEL::doSetParamValue( int aParamIndex, const std::string& aValue )
 void SIM_MODEL::SetParamValue( int aParamIndex, const std::string& aValue,
                                SIM_VALUE::NOTATION aNotation )
 {
-    doSetParamValue( aParamIndex, SIM_VALUE::Normalize( aValue, aNotation ) );
+    // Note: also converts decimal separators to '.'
+    std::string value = SIM_VALUE::ConvertNotation( aValue, aNotation, SIM_VALUE::NOTATION::SI );
+
+    doSetParamValue( aParamIndex, value );
 }
 
 
diff --git a/eeschema/sim/sim_property.cpp b/eeschema/sim/sim_property.cpp
index eba8d7e953..01788333dd 100644
--- a/eeschema/sim/sim_property.cpp
+++ b/eeschema/sim/sim_property.cpp
@@ -158,16 +158,24 @@ bool SIM_STRING_PROPERTY::StringToValue( wxVariant& aVariant, const wxString& aT
     if( m_disabled )
         return false;
 
-    wxString text;
+    wxString text = aText;
 
     if( allowEval() && m_needsEval && m_eval.Process( aText ) )
-        text = m_eval.Result();
-    else
-        text = aText;
+    {
+        double value = SIM_VALUE::ToDouble( m_eval.Result().ToStdString() );
 
-    m_model.SetParamValue( m_paramIndex, std::string( text.ToUTF8() ) );
-    aVariant = GetParam().value;
+        if( isnan( value ) || value == SIM_VALUE::ToDouble( aText.ToStdString() ) )
+        {
+            // Don't mess up user formatting if eval'ing didn't actually change the value.
+        }
+        else
+        {
+            text = SIM_VALUE::Normalize( value );
+        }
+    }
 
+    m_model.SetParamValue( m_paramIndex, text.ToStdString() );
+    aVariant = text.ToStdString();
     return true;
 }
 
diff --git a/eeschema/sim/sim_value.cpp b/eeschema/sim/sim_value.cpp
index 2e30b52fdd..7007ba26ae 100644
--- a/eeschema/sim/sim_value.cpp
+++ b/eeschema/sim/sim_value.cpp
@@ -395,6 +395,19 @@ std::string SIM_VALUE::ConvertNotation( const std::string& aString, NOTATION aFr
 }
 
 
+std::string SIM_VALUE::Normalize( double aValue )
+{
+    double exponent = std::log10( std::abs( aValue ) );
+    int    expReduction = 0;
+
+    std::string prefix = SIM_VALUE_PARSER::ExponentToUnitPrefix( exponent, expReduction,
+                                                                 NOTATION::SI );
+    double reducedValue = aValue / std::pow( 10, expReduction );
+
+    return fmt::format( "{:g}{}", reducedValue, prefix );
+}
+
+
 double SIM_VALUE::ToDouble( const std::string& aString, double aDefault )
 {
     SIM_VALUE_PARSER::PARSE_RESULT parseResult = SIM_VALUE_PARSER::Parse( aString, NOTATION::SI );
diff --git a/eeschema/sim/sim_value.h b/eeschema/sim/sim_value.h
index 521c841a8f..2f9f23618c 100644
--- a/eeschema/sim/sim_value.h
+++ b/eeschema/sim/sim_value.h
@@ -79,11 +79,7 @@ public:
     static std::string ConvertNotation( const std::string& aString, NOTATION aFromNotation,
                                         NOTATION aToNotation );
 
-    static std::string Normalize( const std::string& aString, NOTATION aNotation )
-    {
-        // Note: also converts decimal separators to '.'
-        return ConvertNotation( aString, aNotation, NOTATION::SI );
-    }
+    static std::string Normalize( double aValue );
 
     static std::string ToSpice( const std::string& aString )
     {