bcquality/microsoft/knowledge/events/do-not-bypass-critical-operations-with-ishandled.md
Jesper Schulz-Wedde f19f0618fb
Add events knowledge domain and review leaf skill (#43)
* Add events knowledge domain and review leaf skill

Add a new `events` knowledge domain covering AL events & subscribers,
wired into the AL review pipeline.

- 3 atomic articles (+ .good.al/.bad.al samples) under
  microsoft/knowledge/events/: the IsHandled override pattern, thin
  OnBefore/OnAfter integration-event publishers, and static vs manual
  subscribers.
- New leaf skill microsoft/skills/review/al-events-review.md sourcing the
  events domain.
- Wired into microsoft/skills/review/al-code-review.md (sub-skills + Source
  + description) and README.md (leaf-skill count + domain list).

AL event syntax verified against Microsoft Learn. Samples are
demonstration-only (not compiled by CI). Additive change; no contract change.

Part of #34.

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

* Add 12 general AL event-design articles to events domain

Add 12 atomic knowledge articles under microsoft/knowledge/events covering
general AL event-design best practices: IsHandled initialization and OnAfter
preservation, appending new event parameters, position-based event naming,
reusing/extending events, avoiding per-iteration publishing, Temp-prefixing
temporary record parameters, unabbreviated parameter names, preferring the
this keyword over IncludeSender, avoiding loosely typed parameters, not
mutating existing event contracts, and not bypassing critical operations
with IsHandled. Each article ships a .good.al and .bad.al demonstration
sample (object IDs 50240-50296; not compiled by CI). Extend the
al-events-review leaf Worklist with one targeted check per new rule.

Additive only; no contract or wiring change (events leaf already wired).

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

* Refine events articles after review feedback

Correct wording in five events articles to reflect that AL event
subscribers bind by parameter name, not position:

- add-new-event-parameters-at-the-end: drop the inaccurate claim that
  appending a parameter forces subscribers to be updated or causes wrong
  values; keep the append-at-end best practice.
- do-not-add-ishandled-to-an-existing-event: reframe from "breaking
  change" to the semantic/purpose shift that leaves existing subscribers
  pointless; rename the breaking-change keyword to semantic-change.
- name-events-by-publisher-position: extend the good sample with
  position-named publishers raised from table and report trigger
  contexts.
- initialize-ishandled-to-false-before-publishing: scope the detection
  and best practice to events that actually carry a var IsHandled, so an
  OnBefore with no IsHandled is not flagged.
- do-not-bypass-critical-operations-with-ishandled: add a litmus-test
  definition of a critical operation (code that cannot stand as an
  independent, self-contained unit).

Knowledge-only; no contract or wiring change.

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

* Soften Anti Pattern wording in add-new-event-parameters article

Remove the last name-vs-position misconception from the Anti Pattern so it
is consistent with the corrected Description: mid-list insertion is framed
as noisy and harder to review rather than as forcing subscriber re-mapping.
Detection sentence unchanged.

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

* Add events domain reviewers to CODEOWNERS

Add @AleksandricMarko and @pchriste-microsoft-com as required reviewers
for the events knowledge domain, matching the existing per-domain expert
ownership convention. Inserted in alphabetical order ahead of the
performance line.

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

---------

Co-authored-by: Jesper Schulz-Wedde <jesper.schulzwedde@microsoft.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-06-25 12:24:25 +02:00

2 KiB

bc-version domain keywords technologies countries application-area
all
events
ishandled
critical-operations
posting
data-integrity
ledger
integration-event
safety
al
w1
all

Do not bypass critical operations with IsHandled

Description

The IsHandled override pattern lets a subscriber skip the guarded code entirely. A critical operation is one that cannot stand as an independent, self-contained unit — code whose partial execution or omission leaves the system inconsistent (imbalanced ledgers, orphaned documents, gaps in a number series, or skipped permission checks). That is acceptable around a pure, side-effect-free calculation, but dangerous around critical operations — posting, ledger-entry creation, number-series consumption, and referential-integrity or permission validation. Wrapping those in OnBeforeX(…; var IsHandled); if IsHandled then exit; lets any subscriber silently suppress them, risking imbalanced ledgers, orphaned documents, skipped permission checks, or duplicated numbers — corruption that surfaces far from the subscriber that caused it. Make the calculation overridable, not the commit: expose the value computation through IsHandled, or offer a regular OnAfter… event to adjust results, while the critical work runs unconditionally.

Best Practice

Scope IsHandled to a safe value-calculation block and run the critical operations unconditionally afterwards; or expose a positive OnAfter… event for subscribers to adjust results, rather than a bypass around the commit.

See sample: do-not-bypass-critical-operations-with-ishandled.good.al.

Anti Pattern

An OnBefore… IsHandled guard wrapping a posting or ledger routine — if IsHandled then exit; around the code that creates ledger entries and updates document status — letting subscribers skip the commit. Detection: an if IsHandled then exit; whose skipped body performs posting, ledger writes, number-series consumption, or integrity and permission validation.

See sample: do-not-bypass-critical-operations-with-ishandled.bad.al.