[BACKPORT] fix #4089

- postgres provider: fix detection of field length and precision for char and numeric fields.
- attribute editor: fix validation in case the field length is unknown

Author: jef-n

src/gui/qgsfieldvalidator.cpp

@@ -58,7 +58,7 @@ QgsFieldValidator::QgsFieldValidator( QObject *parent, const QgsField &field )
       }
       else if ( mField.precision() > 0 )
       {
-        QString re = QString( "-?\\d*(\\.\\d{0,%1))?" ).arg( mField.precision() );
+        QString re = QString( "-?\\d*(\\.\\d{0,%1})?" ).arg( mField.precision() );
         mValidator = new QRegExpValidator( QRegExp( re ), parent );
       }
       else

src/providers/postgres/qgspostgresprovider.cpp

@@ -909,7 +909,7 @@ bool QgsPostgresProvider::loadFields()
 
     int fldtyp = PQftype( result, i );
     QString typOid = QString().setNum( fldtyp );
-    int fieldModifier = PQfmod( result, i );
+    int fieldPrec = -1;
     QString fieldComment( "" );
     int tableoid = PQftable( result, i );
 
@@ -924,13 +924,15 @@ bool QgsPostgresProvider::loadFields()
     QString fieldElem = QString::fromUtf8( PQgetvalue( oidResult, 0, 2 ) );
     int fieldSize = QString::fromUtf8( PQgetvalue( oidResult, 0, 3 ) ).toInt();
 
+    QString formattedFieldType;
     if ( tableoid > 0 )
     {
-      sql = QString( "SELECT attnum FROM pg_attribute WHERE attrelid=%1 AND attname=%2" )
+      sql = QString( "SELECT attnum,pg_catalog.format_type(atttypid,atttypmod) FROM pg_attribute WHERE attrelid=%1 AND attname=%2" )
             .arg( tableoid ).arg( quotedValue( fieldName ) );
 
       Result tresult = connectionRO->PQexec( sql );
       QString attnum = QString::fromUtf8( PQgetvalue( tresult, 0, 0 ) );
+      formattedFieldType = QString::fromUtf8( PQgetvalue( tresult, 0, 1 ) );
 
       sql = QString( "SELECT description FROM pg_description WHERE objoid=%1 AND objsubid=%2" )
             .arg( tableoid ).arg( attnum );
@@ -953,20 +955,41 @@ bool QgsPostgresProvider::loadFields()
       {
         fieldType = QVariant::LongLong;
         fieldSize = -1;
+        fieldPrec = 0;
       }
       else if ( fieldTypeName.startsWith( "int" ) ||
                 fieldTypeName == "serial" )
       {
         fieldType = QVariant::Int;
         fieldSize = -1;
+        fieldPrec = 0;
       }
       else if ( fieldTypeName == "real" ||
                 fieldTypeName == "double precision" ||
-                fieldTypeName.startsWith( "float" ) ||
-                fieldTypeName == "numeric" )
+                fieldTypeName.startsWith( "float" ) )
       {
         fieldType = QVariant::Double;
         fieldSize = -1;
+        fieldPrec = 0;
+      }
+      else if ( fieldTypeName == "numeric" )
+      {
+        fieldType = QVariant::Double;
+
+        QRegExp re( "numeric\\((\\d+),(\\d+)\\)" );
+        if ( re.exactMatch( formattedFieldType ) && re.captureCount() == 2 )
+        {
+          fieldSize = re.cap( 1 ).toInt();
+          fieldPrec = re.cap( 2 ).toInt();
+        }
+        else
+        {
+          QgsDebugMsg( QString( "unexpected formatted field type '%1' for field %2" )
+                       .arg( formattedFieldType )
+                       .arg( fieldName ) );
+          fieldSize = -1;
+          fieldPrec = -1;
+        }
       }
       else if ( fieldTypeName == "text" ||
                 fieldTypeName == "bpchar" ||
@@ -983,6 +1006,20 @@ bool QgsPostgresProvider::loadFields()
       else if ( fieldTypeName == "char" )
       {
         fieldType = QVariant::String;
+
+        QRegExp re( "char\\((\\d+)\\)" );
+        if ( re.exactMatch( formattedFieldType ) && re.captureCount() == 1 )
+        {
+          fieldSize = re.cap( 1 ).toInt();
+        }
+        else
+        {
+          QgsDebugMsg( QString( "unexpected formatted field type '%1' for field %2" )
+                       .arg( formattedFieldType )
+                       .arg( fieldName ) );
+          fieldSize = -1;
+          fieldPrec = -1;
+        }
       }
       else
       {
@@ -1018,7 +1055,7 @@ bool QgsPostgresProvider::loadFields()
 
     fields << fieldName;
 
-    attributeFields.insert( i, QgsField( fieldName, fieldType, fieldTypeName, fieldSize, fieldModifier, fieldComment ) );
+    attributeFields.insert( i, QgsField( fieldName, fieldType, fieldTypeName, fieldSize, fieldPrec, fieldComment ) );
   }
 
   return true;