| name | tmdl-review |
| description | Review a TMDL semantic-model diff for breaking schema changes before merging a PBIP change. Compares two versions of the *.tmdl files (a PR, or two git refs) and classifies every change as BREAKING / WARNING / INFO. Use when the user wants to know whether a Power BI / Fabric model change is safe to merge. Triggers — "revisa el diff TMDL", "breaking changes del modelo", "compara el modelo semántico", "¿este cambio rompe el modelo?", "review the TMDL diff", "detect breaking schema changes".
|
| user-invocable | false |
tmdl-review — detect breaking semantic-model changes
PBIP repos store the Power BI / Fabric semantic model as TMDL (*.tmdl) text
files. A diff over those files is hard to read by eye: a dropped column, a changed
dataType, or a deleted measure will break downstream reports, DAX, and refreshes,
but looks the same in raw text as a harmless display-folder rename.
scripts/Tmdl-DiffReview.ps1 parses the model before/after a change and classifies
every schema change by severity.
When to use
- A PR edits
*.tmdl and you need to know whether it is safe to merge.
- Before opening a PR, to self-check your own model change.
- As part of
/board work step 5 — Board-ReviewGate.ps1 runs this automatically
when the PR touches *.tmdl (warn-only; it does not change the gate verdict).
Two modes
PR mode (no local clone needed) — reads the PR's changed *.tmdl via the GitHub
API, fetching base and head content by ref:
$env:GH_TOKEN = [Environment]::GetEnvironmentVariable('GITHUB_TOKEN_PERSONAL','User')
.\scripts\Tmdl-DiffReview.ps1 -Repo <owner/name> -PR <n>
Local mode — diffs *.tmdl with git in the current working copy:
.\scripts\Tmdl-DiffReview.ps1 -Base main -Head HEAD
Severity rules
| Severity | Change |
|---|
| BREAKING | table / column / measure / hierarchy / relationship / role deleted; column dataType changed; column sourceColumn changed; column/measure renamed |
| WARNING | measure / partition-source expression changed; column summarizeBy changed; object becomes hidden; relationship crossFilteringBehavior changed |
| INFO | any addition; formatString / displayFolder / description / lineageTag changes |
A delete + add of the same kind under the same parent, with identical signature
(column dataType+sourceColumn, or measure expression), is reported as
RENAMED (breaking — references by name break) rather than an unrelated pair.
Flags
-FailOnBreaking — exit 1 when any BREAKING change is found (default: warn only,
exit 0). The M3.3 hard merge-block uses this: Board-ReviewGate.ps1 runs the TMDL review
with -FailOnBreaking (alongside Bpa-GateReview.ps1 -FailOn error) and blocks the merge
when either finds a problem in a PR that touches the model (#16).-Json — emit the findings object as JSON instead of the colored report.
Limits (v1, honest)
- The comparison is per file: only changed
*.tmdl are compared. A cross-file
effect (a relationship in an unchanged file referencing a column dropped in a
changed file) is caught only if both files changed.
- The parser is pragmatic and line-based (indentation), not a full TMDL grammar.
Calculation groups, perspectives, translations, and role filter expressions are
not diffed in detail. Table/column/measure/hierarchy/partition/relationship/role
existence and the key breaking properties are covered.
