Regenerate microsoft/knowledge from upstream BCApps instructions

The previous LLM-generated knowledge files contained factual
hallucinations. The most visible was the claim that `FindFirst` /
`FindLast` "forces a full-table scan" on an unfiltered record - it does
not; those APIs return a single row via the current key.

Other inaccuracies the audit found and fixed:

* `FindSet(true)` was described as "taking a LockTable". The correct
  upstream phrasing is that `FindSet(true)` sets
  `ReadIsolation::UpdLock` on the read. UpdLock and LockTable are
  related but distinct mechanisms.
* The list of production-scale tables had been invented beyond the
  upstream source (e.g. "Detailed Cust. Ledg. Entry") without a
  citation. The regenerated list matches the ten tables upstream lists
  with their P95 row counts.
* `SetLoadFields` guidance had been augmented with an extra mechanism
  claim ("the database resolves the filter using the index without
  hydrating the value") not present in upstream.

Approach: full regeneration of `microsoft/knowledge/` from the six
upstream BCApps Code Review instruction files, with Microsoft Learn /
the AL language reference as a secondary source. Every claim in every
regenerated file is anchored to a verbatim upstream quote (or a Learn
URL); the audit trail lives in artifacts/trace-<domain>.json on the
session workspace.

The PR #11 transaction/error-handling cluster is preserved verbatim:

* performance/understand-implicit-transaction-boundary.md
* performance/codeunit-run-as-atomic-sub-operation.{md,good.al,bad.al}
* performance/codeunit-run-requires-prior-commit-inside-transaction.{md,good.al,bad.al}
* performance/use-tryfunction-for-error-catching-not-rollback.{md,good.al,bad.al}
* performance/avoid-commit-inside-loops.{md,good.al,bad.al}
* security/commitbehavior-attribute-scopes-explicit-commits.{md,good.al,bad.al}
* testing/transactionmodel-attribute-governs-test-transactions.{md,good.al,bad.al}

These articles already cite Microsoft Learn and were carefully
cross-referenced; the regeneration skips their topics rather than
duplicating them.

File counts after regeneration:

  performance   35 .md  (5 preserved + 30 new)
  privacy       17 .md
  security      18 .md  (1 preserved + 17 new)
  style         33 .md
  testing        1 .md  (preserved)
  ui            19 .md
  upgrade       18 .md

Total 141 atomic knowledge files, each strictly one rule. All pass
.github/scripts/validate_frontmatter.py with 0 errors and 0 warnings.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
This commit is contained in:
Jesper Schulz-Wedde 2026-05-21 09:53:09 +02:00
parent 613c4b4019
commit a9f3c50863
562 changed files with 6293 additions and 4869 deletions

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---
bc-version: [all]
domain: privacy
keywords: [error, strsubstno, direct-substitution, telemetry, classification, label]
technologies: [al]
countries: [w1]
application-area: [all]
---
# `Error()` with direct substitution parameters is always safe for telemetry
## Description
When `Error()` is called with a format string and direct substitution parameters (`%1`, `%2`, …), the BC platform intercepts the call, inspects each parameter individually, and applies the `DataClassification` of the source field — stripping or masking sensitive data before writing the message to telemetry. This is true regardless of whether a parameter is a record field reference, a local variable, a function return value, or any other expression. Patterns such as `Error('Invalid email: %1', Customer."E-Mail")` are therefore safe even when the parameter is PII: the platform sees `Customer."E-Mail"` as a `CustomerContent` field reference and handles it correctly.
## Best Practice
Pass values to `Error()` as direct substitution parameters — either inline or via a `Label` with `Comment = '%1 = …'` placeholders. Let the platform do the per-parameter classification. This works equally well for record fields, local text variables, and document IDs.
See sample: `error-direct-substitution-safe-for-telemetry.good.al`.
## Anti Pattern
Treating any `Error()` call that mentions PII as a leak. A review skill that flags `Error('Invalid email: %1', EmailAddress)` is wrong; the platform handles that pattern correctly. The only `Error()` shape that genuinely leaks PII to telemetry is the pre-built `StrSubstNo` form covered in `avoid-strsubstno-prebuild-before-error.md`.