Merge 49b14834c4 into b503249751

microsoft/knowledge/data-modeling/tablerelation-field-length-must-match-related-field.bad.al

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+table 50100 "Sample Category"
+{
+    fields
+    {
+        field(1; "Code"; Code[20]) { }
+    }
+    keys
+    {
+        key(PK; "Code") { Clustered = true; }
+    }
+}
+
+table 50102 "Sample Contract"
+{
+    fields
+    {
+        field(1; "Code"; Code[20]) { }
+        // Code[10] cannot hold every "Sample Category"."Code" value (Code[20]).
+        // Compiles without a diagnostic; assigning or validating a category code
+        // longer than 10 characters fails at runtime.
+        field(2; "Category Code"; Code[10])
+        {
+            TableRelation = "Sample Category"."Code";
+        }
+    }
+    keys
+    {
+        key(PK; "Code") { Clustered = true; }
+    }
+}

microsoft/knowledge/data-modeling/tablerelation-field-length-must-match-related-field.good.al

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+enum 50100 "Sample Source Type"
+{
+    Extensible = true;
+
+    value(0; Category) { }
+    value(1; Region) { }
+}
+
+table 50100 "Sample Category"
+{
+    fields
+    {
+        field(1; "Code"; Code[20]) { }
+    }
+    keys
+    {
+        key(PK; "Code") { Clustered = true; }
+    }
+}
+
+table 50101 "Sample Region"
+{
+    fields
+    {
+        field(1; "Code"; Code[10]) { }
+    }
+    keys
+    {
+        key(PK; "Code") { Clustered = true; }
+    }
+}
+
+table 50102 "Sample Contract"
+{
+    fields
+    {
+        field(1; "Code"; Code[20]) { }
+        // Unconditional relation: same type and exactly the same length as
+        // "Sample Category"."Code".
+        field(2; "Category Code"; Code[20])
+        {
+            TableRelation = "Sample Category"."Code";
+        }
+        field(3; "Source Type"; Enum "Sample Source Type") { }
+        // All branches conditional: at least as long as the longest related
+        // field (Code[20] covers both Code[20] and Code[10]).
+        field(4; "Source Code"; Code[20])
+        {
+            TableRelation = if ("Source Type" = const(Category)) "Sample Category"."Code"
+            else
+            if ("Source Type" = const(Region)) "Sample Region"."Code";
+        }
+        // Filter field: holds a filter expression, not one code, so it is
+        // deliberately longer and opts out of relation validation.
+        field(5; "Category Filter"; Code[250])
+        {
+            TableRelation = "Sample Category"."Code";
+            ValidateTableRelation = false;
+        }
+    }
+    keys
+    {
+        key(PK; "Code") { Clustered = true; }
+    }
+}

microsoft/knowledge/data-modeling/tablerelation-field-length-must-match-related-field.md

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+---
+bc-version: [all]
+domain: data-modeling
+keywords: [tablerelation, field-length, code, text, conditional-relation, lookup]
+technologies: [al]
+countries: [w1]
+application-area: [all]
+---
+
+# A TableRelation field's length must match the related field
+
+## Description
+
+`TableRelation` points a field at another table, or at a specific field of it with `Table.Field`. The relation is also used to validate entries and to drive the lookup. A referencing field that is shorter than the related field compiles without a length diagnostic: verified with AL compiler 30.0 and the CodeCop, UICop and PerTenantExtensionCop analyzers. Compare `AL0685`, which does warn about an analogous length mismatch for a FlowField's `CalcFormula` target.
+
+A shorter field compiles cleanly and works for every value that happens to fit. It fails only when a real related value is longer than the field. For example, a `Code[10]` field related to a table with a `Code[20]` key fails when a 15-character code is assigned or validated into it. The runtime error reads "The length of the string is N, but it must be less than or equal to M characters."
+
+The length Business Central's own relation check expects depends on whether the field has an unconditional relation:
+
+- **At least one unconditional relation**, either a plain `TableRelation = X` or an unconditional branch: the field must have the **exact** length of the longest related field and the same type.
+- **Only conditional relations** (`if (...) X else if (...) Y`): the field must be **at least** as long as the longest related field. A longer field is accepted.
+
+For the type, the check requires the related field's type, or `Text` when the related fields mix `Code` and `Text`. Only under all-conditional relations, and only when the required type is `Code`, may the field be `Text` instead.
+
+The check skips any field that sets `ValidateTableRelation = false` or `TestTableRelation = false`. The Base Application sets `ValidateTableRelation = false` on filter and totaling fields, which hold a filter expression rather than one key value. Such a field may be longer than the related field. A field that is shorter than the related field is still a defect even with either property set to `false`, because a real related value still overflows it at runtime.
+
+The check is codeunit 134926 "Table Relation Test" in the BC test app. Its validation test is `[Scope('OnPrem')]`, so it runs only on an on-premises test surface. It is not a compile-time guarantee. See [`table-relation-test-exclude-known-invalid-relations-via-event.md`](../testing/table-relation-test-exclude-known-invalid-relations-via-event.md) for how that check evaluates relations and how to exclude a known exception.
+
+## Best Practice
+
+Before you add or change a `TableRelation`, read the declared type and length of every related field from its table definition. Lengths vary from table to table, so don't assume a typical `Code[10]` or `Code[20]`. Then size the field:
+
+- For an unconditional relation, give it the same type and exact length as the related field, unless the field holds a filter expression and sets `ValidateTableRelation = false`.
+- For an all-conditional relation, make it at least as long as the longest branch target.
+
+When a `tableextension` adds a branch with `modify(...)`, check the new target's length against the field's existing declaration too.
+
+See sample: [`tablerelation-field-length-must-match-related-field.good.al`](tablerelation-field-length-must-match-related-field.good.al).
+
+## Anti Pattern
+
+A field whose declared `Code`/`Text` length is shorter than the field it relates to. One example is a `Code[10]` field with `TableRelation` to a table keyed on `Code[20]`. Another is a conditional relation where one branch targets a longer field than the declaration. Both compile without a diagnostic and fail at runtime once a real, longer value is used. This applies whether or not `ValidateTableRelation` or `TestTableRelation` is `false`. The Base Application has an instance: "Financial Report Schedule"."Excel Template Code" is `Code[20]` and relates, with a `where` filter, to "Fin. Report Excel Template".Code, which is `Code[50]`.
+
+A field that is longer than its related field under an unconditional relation, with neither `ValidateTableRelation` nor `TestTableRelation` set to `false`, is a lesser deviation. It holds every valid value, but it is rejected by codeunit 134926's check and accepts values that can never satisfy the relation.
+
+See sample: [`tablerelation-field-length-must-match-related-field.bad.al`](tablerelation-field-length-must-match-related-field.bad.al).
+
+Related: [`transferfields-mirrored-fields-must-match-type-and-length.md`](transferfields-mirrored-fields-must-match-type-and-length.md) covers the same length-mismatch failure between fields that `TransferFields` connects.
+
+## Source
+
+- [TableRelation property](https://learn.microsoft.com/dynamics365/business-central/dev-itpro/developer/properties/devenv-tablerelation-property): syntax `<TableName>[.<FieldName>]`, conditional `IF ... ELSE` relations, and use of the relation to validate entries.
+- [Compiler Warning (future error) AL0685](https://learn.microsoft.com/dynamics365/business-central/dev-itpro/developer/diagnostics/diagnostic-al685): the analogous FlowField length diagnostic, which warns that the mismatch "could result in a runtime error".
+- BCApps [`src/Layers/W1/Tests/Misc/TableRelationTest.Codeunit.al`](https://github.com/microsoft/BCApps/blob/main/src/Layers/W1/Tests/Misc/TableRelationTest.Codeunit.al): line 46 says "Fields must have the exact length of the largest field they relate to". Lines 48-49 skip a field unless both "Test Table Relation" and "Validate Table Relation" are true. Lines 68-84 apply `Field.Len < MaxRelatedFieldLength` when every relation is conditional and `Field.Len <> MaxRelatedFieldLength` otherwise. Line 15 is `[Scope('OnPrem')]`.
+- [ValidateTableRelation property](https://learn.microsoft.com/dynamics365/business-central/dev-itpro/developer/properties/devenv-validatetablerelation-property) and [TestTableRelation property](https://learn.microsoft.com/dynamics365/business-central/dev-itpro/developer/properties/devenv-testtablerelation-property): both default to `true`, and setting `ValidateTableRelation` to `false` should be paired with `TestTableRelation = false`.
+- Deliberately longer filter fields with `ValidateTableRelation = false` in BCApps W1 Base Application:
+  - [`src/Layers/W1/BaseApp/Warehouse/Request/WarehouseSourceFilter.Table.al`](https://github.com/microsoft/BCApps/blob/main/src/Layers/W1/BaseApp/Warehouse/Request/WarehouseSourceFilter.Table.al) lines 44-49: "Variant Code Filter" `Code[100]` relates to "Item Variant".Code (`Code[10]`).
+  - [`src/Layers/W1/BaseApp/Finance/Analysis/AnalysisViewFilter.Table.al`](https://github.com/microsoft/BCApps/blob/main/src/Layers/W1/BaseApp/Finance/Analysis/AnalysisViewFilter.Table.al) lines 49-54: "Dimension Value Filter" `Code[250]` relates to "Dimension Value".Code (`Code[20]`).
+  - [`src/Layers/W1/BaseApp/Projects/Project/Job/JobTask.Table.al`](https://github.com/microsoft/BCApps/blob/main/src/Layers/W1/BaseApp/Projects/Project/Job/JobTask.Table.al) lines 290-295: Totaling `Text[250]` relates to "Job Task"."Job Task No." (`Code[20]`).
+- BCApps [`src/Layers/W1/BaseApp/Finance/FinancialReports/FinancialReportSchedule.Table.al`](https://github.com/microsoft/BCApps/blob/main/src/Layers/W1/BaseApp/Finance/FinancialReports/FinancialReportSchedule.Table.al) lines 48-51: "Excel Template Code" `Code[20]` relates to [`FinReportExcelTemplate.Table.al`](https://github.com/microsoft/BCApps/blob/main/src/Layers/W1/BaseApp/Finance/FinancialReports/FinReportExcelTemplate.Table.al) field Code (`Code[50]`, line 33), an instance of the shorter-field anti-pattern.
+- BCApps [`src/Apps/W1/Subcontracting/Test/Tests/SubcCommentsAttachmentTest.Codeunit.al`](https://github.com/microsoft/BCApps/blob/main/src/Apps/W1/Subcontracting/Test/Tests/SubcCommentsAttachmentTest.Codeunit.al) line 295 asserts the runtime text "The length of the string is 101".

microsoft/knowledge/testing/recordref-open-temp-parameter-defeats-real-table-checks.bad.al

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+// Test-library-style helper (uses "Library - Utility"); not a Subtype = Test codeunit.
+codeunit 50150 "Sample Payment Terms Codes"
+{
+    procedure GenerateUnusedPaymentTermsCode(): Code[10]
+    var
+        PaymentTerms: Record "Payment Terms";
+        LibraryUtility: Codeunit "Library - Utility";
+        RecRef: RecordRef;
+        FieldRef: FieldRef;
+        NewCode: Code[10];
+    begin
+        // Temp = true: RecRef is an empty temporary instance, so IsEmpty()
+        // is true on the first pass and existing Payment Terms are never seen.
+        RecRef.Open(Database::"Payment Terms", true, CompanyName());
+        FieldRef := RecRef.Field(PaymentTerms.FieldNo(Code));
+        repeat
+            NewCode := CopyStr(LibraryUtility.GenerateRandomXMLText(MaxStrLen(NewCode)), 1, MaxStrLen(NewCode));
+            FieldRef.SetRange(NewCode);
+        until RecRef.IsEmpty();
+        exit(NewCode);
+    end;
+}

microsoft/knowledge/testing/recordref-open-temp-parameter-defeats-real-table-checks.good.al

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+// Test-library-style helper (uses "Library - Utility"); not a Subtype = Test codeunit.
+codeunit 50150 "Sample Payment Terms Codes"
+{
+    procedure GenerateUnusedPaymentTermsCode(): Code[10]
+    var
+        PaymentTerms: Record "Payment Terms";
+        LibraryUtility: Codeunit "Library - Utility";
+        RecRef: RecordRef;
+        FieldRef: FieldRef;
+        NewCode: Code[10];
+    begin
+        // Temp = false: the loop checks the persisted Payment Terms rows.
+        RecRef.Open(Database::"Payment Terms", false, CompanyName());
+        FieldRef := RecRef.Field(PaymentTerms.FieldNo(Code));
+        repeat
+            NewCode := CopyStr(LibraryUtility.GenerateRandomXMLText(MaxStrLen(NewCode)), 1, MaxStrLen(NewCode));
+            FieldRef.SetRange(NewCode);
+        until RecRef.IsEmpty();
+        exit(NewCode);
+    end;
+
+    procedure GetFieldFilterFromView(TableNo: Integer; TableView: Text; FieldNo: Integer): Text
+    var
+        RecRef: RecordRef;
+        FieldRef: FieldRef;
+    begin
+        // Temp = true is correct here: the RecordRef only parses a view and
+        // never reads rows.
+        RecRef.Open(TableNo, true);
+        RecRef.SetView(TableView);
+        FieldRef := RecRef.Field(FieldNo);
+        exit(FieldRef.GetFilter());
+    end;
+}

microsoft/knowledge/testing/recordref-open-temp-parameter-defeats-real-table-checks.md

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+---
+bc-version: [all]
+domain: testing
+keywords: [recordref, open, temporary, isempty, existence-check, uniqueness]
+technologies: [al]
+countries: [w1]
+application-area: [all]
+---
+
+# RecordRef.Open with Temp = true cannot check the real table
+
+## Description
+
+`RecordRef.Open(No: Integer [, Temp: Boolean] [, CompanyName: Text])` always takes a real table number. When `Temp` is `true`, though, the `RecordRef` refers to a temporary instance of that table. That instance starts empty and never contains the persisted rows. Microsoft Learn's example opens table 27 temporarily and notes that `Find('-')` "returns false" because "there are no records in a temporary table". So `IsEmpty`, `Find*`, `Next`, `Get` or `Count` on a temp-opened `RecordRef` only sees rows the same code inserted into it. These calls can't answer "does this value already exist in the table?"
+
+The defect is easy to miss at the call site. `Temp` is a positional, unnamed Boolean, the table number is genuine, and the code compiles without a diagnostic. The usual shape is a generate-until-unused loop: the code sets a range on a field and repeats `until RecRef.IsEmpty()`. That loop exits on its first pass and returns a value that may already exist. The defect then shows up later as a duplicate-key error or a wrong lookup, often only once the table holds data.
+
+The shape occurs wherever `RecordRef` is used. This article sits in the testing domain because generic test-library helpers, which work on any table number, are where it typically appears. For how specific `LibraryUtility` helpers behave, including `GenerateRandomCode`'s temporary open, see [`use-generateguid-for-unique-test-fixture-values.md`](use-generateguid-for-unique-test-fixture-values.md). That article owns guidance on which helper to call.
+
+## Best Practice
+
+When the code that follows has to see persisted rows, open with `Temp = false` or omit the parameter. Learn's first example omits it so the table "will not be open as temporary table".
+
+`Temp = true` is correct when the `RecordRef` is deliberately a scratch instance that never answers existence questions about the real table, for example:
+
+- A field-validation sandbox: insert a temporary row, then `Validate` a field on it.
+- Parsing a table view with `SetView` and reading `GetFilter`.
+- Reading table metadata such as `SystemIdNo`.
+
+See sample: [`recordref-open-temp-parameter-defeats-real-table-checks.good.al`](recordref-open-temp-parameter-defeats-real-table-checks.good.al).
+
+## Anti Pattern
+
+`RecRef.Open(<table>, true[, ...])` followed, on the same `RecordRef` and with no `Insert` into it, by `IsEmpty`, `Find`, `FindFirst`, `FindLast`, `FindSet`, `Next`, `Get` or `Count` whose result decides whether a value already exists in the table. The classic case is a uniqueness loop ending `until RecRef.IsEmpty()`.
+
+See sample: [`recordref-open-temp-parameter-defeats-real-table-checks.bad.al`](recordref-open-temp-parameter-defeats-real-table-checks.bad.al).
+
+## Source
+
+- [RecordRef.Open method](https://learn.microsoft.com/dynamics365/business-central/dev-itpro/developer/methods-auto/recordref/recordref-open-method): the syntax, Example 1 (parameters omitted, not temporary) and Example 2 (temporary open is empty, `Find('-')` returns false).
+- BCApps [`src/Layers/W1/Tests/ApplicationTestLibrary/LibraryUtility.Codeunit.al`](https://github.com/microsoft/BCApps/blob/main/src/Layers/W1/Tests/ApplicationTestLibrary/LibraryUtility.Codeunit.al): `GenerateRandomCode` opens with `true` at line 288 and loops `until RecRef.IsEmpty()`. `GenerateRandomCodeWithLength` opens with `false` at line 309.
+- Legitimate `Temp = true` uses in BCApps W1:
+  - [`src/Layers/W1/BaseApp/Inventory/Item/ItemTempl.Table.al`](https://github.com/microsoft/BCApps/blob/main/src/Layers/W1/BaseApp/Inventory/Item/ItemTempl.Table.al) line 1255: temporary `Item` insert plus `Validate`.
+  - [`src/Apps/W1/Quality Management/app/src/Utilities/QltyFilterHelpers.Codeunit.al`](https://github.com/microsoft/BCApps/blob/main/src/Apps/W1/Quality%20Management/app/src/Utilities/QltyFilterHelpers.Codeunit.al) line 942: `SetView` plus `GetFilter`.
+  - [`src/Layers/W1/BaseApp/Integration/SynchEngine/IntegrationRecordSynch.Codeunit.al`](https://github.com/microsoft/BCApps/blob/main/src/Layers/W1/BaseApp/Integration/SynchEngine/IntegrationRecordSynch.Codeunit.al) line 221: `SplitLocalTableFilter` splits a table filter, reading only `SystemIdNo` from the temporary open.