bcquality/microsoft/knowledge/style/no-else-after-terminating-statement.md
Jesper Schulz-Wedde a9f3c50863 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>
2026-05-21 09:53:09 +02:00

1.5 KiB

bc-version domain keywords technologies countries application-area
all
style
else
exit
break
skip
quit
error
terminating
control-flow
al
w1
all

Omit else when the then branch ends with exit, break, skip, quit, or error

Description

When the then branch of an if ends in a terminating statement — exit, break, skip, quit, or error — the else branch becomes the natural fall-through. if Cond then exit; DoX(); and if Cond then exit else DoX(); are equivalent, and the second form adds a layer of nesting that the reader has to mentally flatten. The same applies to Error(...): if IsAdjmtBinCodeChanged() then Error(AdjmtErr) else Error(BinErr); is better written as if IsAdjmtBinCodeChanged() then Error(AdjmtErr); Error(BinErr); — the second Error is always reached when the first branch is not taken.

Best Practice

Drop the else when the then branch unconditionally exits the procedure or the enclosing loop. The body that would have been inside else becomes the unindented continuation.

See sample: no-else-after-terminating-statement.good.al.

Anti Pattern

An if … then Error(…) else Error(…) pair where both branches terminate. The else is structural noise — the reader cannot tell at a glance whether it exists to handle an actual continuation or simply mirrors the then. The fix is to drop else and let the second Error fall through naturally.

See sample: no-else-after-terminating-statement.bad.al.