fix: ConcurrencyMode=Fixed property marked Creatable in OData import (issue #525)

When importing entities from an OData service (e.g. TripPin Airline.Concurrency),
properties with ConcurrencyMode="Fixed" (OData v3 optimistic concurrency token)
were being marked Creatable=true in the generated external entity. Studio Pro
then rejected the model with:

  'Concurrency' is marked Creatable=True in the OData service, but False in the app.

Root cause: xmlProperty did not capture the ConcurrencyMode XML attribute, so
parseXmlEntityType never set Computed=true for those properties. The creatable
flag check (p.Computed → creatable=false) was therefore never triggered.

Fix: parse ConcurrencyMode from the <Property> element and treat "Fixed" as
equivalent to Computed=true — the server owns the value, the client cannot set it.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: ako

mdl/types/edmx.go

@@ -317,6 +317,11 @@ func parseXmlEntityType(et *xmlEntityType) *EdmEntityType {
 			v := p.Nullable != "false"
 			prop.Nullable = &v
 		}
+		// ConcurrencyMode="Fixed" (OData v3) marks a property as an optimistic
+		// concurrency token — the server manages it, the client cannot set it.
+		if p.ConcurrencyMode == "Fixed" {
+			prop.Computed = true
+		}
 		for _, ann := range p.Annotations {
 			switch ann.Term {
 			case "Org.OData.Core.V1.Computed":
@@ -474,12 +479,13 @@ type xmlPropertyRef struct {
 }
 
 type xmlProperty struct {
-	Name        string          `xml:"Name,attr"`
-	Type        string          `xml:"Type,attr"`
-	Nullable    string          `xml:"Nullable,attr"`
-	MaxLength   string          `xml:"MaxLength,attr"`
-	Scale       string          `xml:"Scale,attr"`
-	Annotations []xmlAnnotation `xml:"Annotation"`
+	Name            string          `xml:"Name,attr"`
+	Type            string          `xml:"Type,attr"`
+	Nullable        string          `xml:"Nullable,attr"`
+	MaxLength       string          `xml:"MaxLength,attr"`
+	Scale           string          `xml:"Scale,attr"`
+	ConcurrencyMode string          `xml:"ConcurrencyMode,attr"` // OData v3: "Fixed" = optimistic concurrency token
+	Annotations     []xmlAnnotation `xml:"Annotation"`
 }
 
 type xmlNavigationProperty struct {

mdl/types/edmx_test.go

@@ -353,3 +353,48 @@ func TestParseEdmx_ExternalAnnotations_WithoutSlash(t *testing.T) {
 		t.Error("expected Updatable=true from external annotation without slash prefix")
 	}
 }
+
+// TestParseEdmx_ConcurrencyModeFixed verifies that a property with
+// ConcurrencyMode="Fixed" (OData v3 ETag token) is treated as Computed=true
+// so that mxcli does not mark it as Creatable in the generated external entity.
+// Regression test for issue #525 (TripPin Airline.Concurrency).
+func TestParseEdmx_ConcurrencyModeFixed(t *testing.T) {
+	xml := `<?xml version="1.0" encoding="utf-8"?>
+<edmx:Edmx Version="1.0" xmlns:edmx="http://schemas.microsoft.com/ado/2007/06/edmx">
+  <edmx:DataServices m:DataServiceVersion="3.0" xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata">
+    <Schema Namespace="TripPin" xmlns="http://schemas.microsoft.com/ado/2009/11/edm">
+      <EntityType Name="Airline">
+        <Key><PropertyRef Name="AirlineCode" /></Key>
+        <Property Name="AirlineCode" Type="Edm.String" Nullable="false" />
+        <Property Name="Name"        Type="Edm.String" Nullable="false" />
+        <Property Name="Concurrency" Type="Edm.Int64"  ConcurrencyMode="Fixed" />
+      </EntityType>
+      <EntityContainer Name="TripPinServiceRW" m:IsDefaultEntityContainer="true">
+        <EntitySet Name="Airlines" EntityType="TripPin.Airline" />
+      </EntityContainer>
+    </Schema>
+  </edmx:DataServices>
+</edmx:Edmx>`
+
+	doc, err := ParseEdmx(xml)
+	if err != nil {
+		t.Fatalf("ParseEdmx error: %v", err)
+	}
+	if len(doc.Schemas) == 0 || len(doc.Schemas[0].EntityTypes) == 0 {
+		t.Fatal("expected at least one entity type")
+	}
+	et := doc.Schemas[0].EntityTypes[0]
+	var concProp *EdmProperty
+	for _, p := range et.Properties {
+		if p.Name == "Concurrency" {
+			concProp = p
+			break
+		}
+	}
+	if concProp == nil {
+		t.Fatal("expected Concurrency property in parsed entity type")
+	}
+	if !concProp.Computed {
+		t.Error("ConcurrencyMode='Fixed' must set Computed=true so the attribute is not marked Creatable (issue #525)")
+	}
+}