Scope DataClassification inheritance to fields declared in the table

Table-level DataClassification is the effective default only for Normal
fields declared inside that table object. A tableextension cannot set the
property (AL0246) and its added fields do not inherit the base table value,
so AS0016 still requires each of them to classify itself. State this in both
privacy articles so the guidance cannot suppress genuine findings on the
tableextension pattern, which is how most partner code adds fields.

Also narrow the inheritance claim to verified AppSourceCop behaviour rather
than asserting platform-level resolution, and make the sample's table-level
default semantically representative of its fields while keeping a legitimate
field-level override and demonstrating the tableextension boundary.

Verified with alc.exe 18.0.37.11445 + Microsoft.Dynamics.Nav.AppSourceCop.dll:
the revised sample produces no AS0016, and removing the explicit
classification from the tableextension field makes AS0016 fire.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

microsoft/knowledge/privacy/data-classification-required-on-pii-fields.md

@@ -11,7 +11,7 @@ application-area: [all]
 
 ## Description
 
-`DataClassification` tells the platform what kind of data a table field stores so that telemetry, GDPR data-subject requests, and the platform's audit surfaces can treat it correctly. A field can declare its own value or inherit the table-level value. When neither scope supplies a valid classification, the field remains `ToBeClassified` — a placeholder meaning "not yet reviewed", not a safe default. Leaving a field that actually holds PII (an email address, a customer name, an employee code) as `ToBeClassified`, or classifying it as `SystemMetadata` ("no user or customer data"), are both under-classifications and privacy bugs, even though the code still compiles.
+`DataClassification` tells the platform what kind of data a table field stores so that telemetry, GDPR data-subject requests, and the platform's audit surfaces can treat it correctly. A field declared inside a table object can set its own value or inherit a valid table-level value; a field added by a `tableextension` has no table-level value to inherit and must always set its own. When neither scope supplies a valid classification, the field remains `ToBeClassified` — a placeholder meaning "not yet reviewed", not a safe default. Leaving a field that actually holds PII (an email address, a customer name, an employee code) as `ToBeClassified`, or classifying it as `SystemMetadata` ("no user or customer data"), are both under-classifications and privacy bugs, even though the code still compiles.
 
 ## Best Practice
 

microsoft/knowledge/privacy/table-level-data-classification-cascades.good.al

@@ -7,17 +7,16 @@ table 50202 "System Configuration Log"
         field(1; "Entry No."; Integer)
         {
         }
-        field(2; "Changed By"; Code[50])
+        field(2; "Setting Name"; Text[100])
+        {
+        }
+        field(3; "Changed At"; DateTime)
+        {
+        }
+        field(4; "Changed By"; Code[50])
         {
             DataClassification = EndUserIdentifiableInformation;
         }
-        field(3; "Change Description"; Text[250])
-        {
-            DataClassification = CustomerContent;
-        }
-        field(4; "Changed At"; DateTime)
-        {
-        }
     }
 
     keys
@@ -25,3 +24,17 @@ table 50202 "System Configuration Log"
         key(PK; "Entry No.") { Clustered = true; }
     }
 }
+
+tableextension 50203 "System Config Log Correlation" extends "System Configuration Log"
+{
+    fields
+    {
+        // A table extension cannot set the table-level property and does not inherit
+        // the base table's default, so this field must classify itself even though
+        // SystemMetadata is the value the base table already declares.
+        field(50203; "Correlation Id"; Guid)
+        {
+            DataClassification = SystemMetadata;
+        }
+    }
+}

microsoft/knowledge/privacy/table-level-data-classification-cascades.md

@@ -1,7 +1,7 @@
 ---
 bc-version: [all]
 domain: privacy
-keywords: [data-classification, table-level, field-inheritance, appsourcecop, as0016, false-positive]
+keywords: [data-classification, table-level, field-inheritance, tableextension, appsourcecop, as0016, false-positive]
 technologies: [al]
 countries: [w1]
 application-area: [all]
@@ -11,14 +11,14 @@ application-area: [all]
 
 ## Description
 
-A valid table-level `DataClassification` is the effective default for fields that do not declare their own value. A field-level value overrides that default only for the field on which it is set. AppSourceCop AS0016 accepts Normal fields that inherit a valid table classification; they do not remain `ToBeClassified`. FlowFields and FlowFilters are handled separately by the platform and are covered by `flowfield-flowfilter-classification-systemmetadata.md`.
+A valid table-level `DataClassification` is the effective default for the Normal fields declared inside that table object when they do not declare their own value, and AppSourceCop AS0016 accepts those fields rather than reporting them as unclassified. A field-level value overrides that default only for the field on which it is set. The default does not cross object boundaries: a `tableextension` cannot set the table-level property, and the fields it adds do not inherit the base table's value, so every Normal field a table extension adds must classify itself. FlowFields and FlowFilters are handled separately by the platform and are covered by `flowfield-flowfilter-classification-systemmetadata.md`.
 
 ## Best Practice
 
-Use a table-level classification when it accurately describes the table's fields, and add a field-level classification only where a field stores a different kind of data. Do not flag a Normal field solely because it omits an explicit property when its table supplies a valid default; verify whether the inherited value matches the field's data instead.
+Use a table-level classification when it accurately describes the table's fields, and add a field-level classification only where a field stores a different kind of data. Do not flag a Normal field solely because it omits an explicit property when its own table supplies a valid default; verify whether the inherited value matches the field's data instead. A `tableextension` has no default to inherit, so require an explicit `DataClassification` on every Normal field it adds.
 
 See sample: `table-level-data-classification-cascades.good.al`.
 
 ## Anti Pattern
 
-Reporting every Normal field without an explicit `DataClassification` when the table already supplies a valid default, or requiring redundant field-level declarations that repeat the table value. A real issue exists when neither scope supplies a valid classification, or when a field's data requires an override of the inherited value.
+Reporting every Normal field without an explicit `DataClassification` when its own table already supplies a valid default, or requiring redundant field-level declarations that repeat the table value. The mirror-image mistake is waving through an unclassified Normal field added by a `tableextension` because the base table carries a default — a table extension inherits nothing. A real issue exists when neither scope supplies a valid classification, when a field's data requires an override of the inherited value, or when the field is added by a table extension.