Add TransferFields SkipFieldsNotMatchingType guidance

[Yahya Touil (yahyatouil-dev)]

What

One knowledge rule: don't use TransferFields(..., SkipFieldsNotMatchingType: true)
as a blanket way to keep two evolving tables transferring without
errors, when the destination actually depends on every source field
being copied.

Why this belongs in BCQuality

TransferFields only errors on a type mismatch when both tables are
in the same extension - cross-extension mismatches are already
skipped by default, flag or not. That distinction isn't obvious from
the method signature, and it's exactly the kind of thing where an AI
(or a dev in a hurry) reaches for SkipFieldsNotMatchingType = true
to make a compile/runtime error go away without noticing a field
silently stopped being copied.

Files

• community/knowledge/data-modeling/transferfields-skip-type-mismatch-can-drop-data.md
• .good.al - explicit field-by-field mapping with Evaluate for the
  type conversion, so a bad value fails loudly instead of vanishing
• .bad.al - two tables in the same app, TransferFields(Source, true, true),
  Reference silently dropped because it's Code[20] on one side and
  Integer on the other

Verified against

• Record.TransferFields(var Record, Boolean, Boolean) - Microsoft Learn
• Confirmed the same-extension vs. cross-extension error behavior
  independently against community testing before writing the rule

One concern, one file, community layer.

[Yahya Touil (yahyatouil-dev)]

@microsoft-github-policy-service agree