Merge worktree-fr5c-finalize-2026-05-27 — FR5c finalize (reconcile overlay-attr-last-writer-wins across all 4 ports)

Author: dmealing

fixtures/conformance/overlay-attr-last-writer-wins/expected-errors.json

@@ -0,0 +1,15 @@
+{
+  "errors": [
+    {
+      "code": "ERR_MERGE_CONFLICT",
+      "source": {
+        "format": "merged",
+        "files": [
+          "meta.commerce.json",
+          "meta.commerce.overlay.json"
+        ]
+      }
+    }
+  ],
+  "warnings": []
+}

server/csharp/MetaObjects.Conformance.Tests/conformance-expected-failures.json

@@ -1,8 +1,6 @@
 {
   "language": "csharp",
   "_comment": "FR5a envelope-shape gates: TS is the reference port for source.format / source.files / source.jsonPath. C# is now reconciled with TS on the JSON-side FR5a envelopes (parser malformed-JSON catch builds a $-rooted JsonSource with the source-file name; inline-attr loop reports ERR_RESERVED_ATTR / ERR_UNKNOWN_ATTR / ERR_BAD_ATTR_VALUE at the parent's path — not key-deeper). Keep this file as the documented ledger surface.",
-  "_notes": "FR5c (2026-05-27): ERR_MERGE_CONFLICT now fires when an `overlay: true` reopen sets the same `@attr` to a different non-empty value (cross-port contract per ADR-0009). The `overlay-attr-last-writer-wins` fixture predates FR5c and exercises exactly that case (`@displayName` flips v1→v2 across two files). TS's conformance runner still PASSES this fixture because TS's runner does not gate tree-check on the presence of unexpected errors; C#'s runner DOES gate (matches Java). Listing here documents the cross-port runner-strictness divergence (TS-side runner change is the proper fix; out-of-scope for FR5c port). FR5d (finalized 2026-05-27, all four ports): reference-resolution errors emit format=resolved with referrer + target; the cross-port fixtures now encode the resolved envelope and all four ports load byte-identically.",
-  "fixtures": [
-    "overlay-attr-last-writer-wins"
-  ]
+  "_notes": "FR5c (finalized 2026-05-27, all four ports): merge-phase contributors + ERR_MERGE_CONFLICT envelope + WARN_DUPLICATE_DECLARATION. The `overlay-attr-last-writer-wins` fixture now declares its ERR_MERGE_CONFLICT in `expected-errors.json` and asserts identically across all four ports — no ledger entry needed. FR5d (finalized 2026-05-27, all four ports): reference-resolution errors emit format=resolved with referrer + target; the cross-port fixtures now encode the resolved envelope and all four ports load byte-identically.",
+  "fixtures": []
 }

spec/conformance-tests.md

@@ -116,13 +116,15 @@ Pre-FR5a fixtures using the legacy `[{"code": "..."}]` array shape get only the
 
 ### Multi-file load order (FR5c)
 
-When a fixture's `input/` directory contains more than one `meta.*.json` file, every port loads them in **case-sensitive alphabetical order of basename** before merging. This is a cross-port contract — the order determines:
+Finalized 2026-05-27 across all four ports (TS / C# / Java / Python). When a fixture's `input/` directory contains more than one `meta.*.json` file, every port loads them in **case-sensitive alphabetical order of basename** before merging. This is a cross-port contract — the order determines:
 
 - which file is the `overlay-base` (alphabetically first) and which are `overlay-extension`s on a merged node's `source.contributors[]`;
 - the `files[]` list inside an `ERR_MERGE_CONFLICT` or `WARN_DUPLICATE_DECLARATION` envelope (also alphabetical, byte-identical across ports).
 
 Last-writer-wins still governs non-conflicting attr overlays (one side unset, or both sides set to the same value). When both contributors set the same `@attr` to *different* non-empty values, the loader raises `ERR_MERGE_CONFLICT` with a `format: "merged"` envelope listing both contributors. When two files declare a node and the second contributes no semantic change (per the FR5a `semantic_diff`), the loader emits `WARN_DUPLICATE_DECLARATION` and the merged node's `source` is **not** upgraded to `format: "merged"`.
 
+**WARN envelope-shape assertion**: as of FR5c-finalize the cross-port runners assert envelope shape on `errors[]` but compare `warnings[]` as a flat string list against `expected-warnings.json`. The error-side envelope assertion (code + source.format + source.files + source.jsonPath) is the cross-port contract; lifting the same assertion onto warnings is queued as follow-up work and is gated on a fixture migration from `expected-warnings.json` (string array) to `expected-errors.json#warnings[]` (envelope shape). All four ports currently exercise the FR5c `warning-duplicate-declaration` fixture under the string-list contract.
+
 ## TS conformance runner
 
 Lives at `typescript/packages/metadata/test/conformance.test.ts`. Algorithm: