From 13c4b89a90a8ddd9373dd24b2db6d3f56b7c3a34 Mon Sep 17 00:00:00 2001
From: hyperpolymath <6759885+hyperpolymath@users.noreply.github.com>
Date: Sun, 31 May 2026 12:15:11 +0100
Subject: [PATCH] =?UTF-8?q?feat(migration/app/proven):=20port=20ProvenErro?=
 =?UTF-8?q?r.affine=20(megaport=20STEP=208=20=E2=80=94=20single-file=20fol?=
 =?UTF-8?q?low-up)?=
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Ports src/app/proven/ProvenError.res (32 LoC) to Mode-A
AffineScript. Self-contained error-types module — pure data record
+ 5 constructor helpers + toString. No FFI, no cross-module deps,
no Tea_/Pixi/Gossamer surface.

Type checks against AffineScript stdlib.

Translation choices:
- record-field punning `{operation}` → explicit `#{operation: operation}`
- labelled args `(~name: T)` → positional `(name: T)` (AS has no labels)
- template literal `` `[${a}] ${b}` `` → `"[" ++ a ++ "] " ++ b` (no JS templates)

What this PR is NOT
  Does NOT replace src/app/proven/ProvenError.res. Consumers
  (SafeFloat, SafeJson, SafeAngle) still reference the .res — those
  ports need cross-module `use` resolution (#228 family) before they
  can swap to the .affine.

Refs standards#279 (megaport STEP 8). Adjacent to idaptik#110 which
landed the first migration/shared/ Mode-A file.
---
 migration/app/proven/ProvenError.affine | 59 +++++++++++++++++++++++++
 1 file changed, 59 insertions(+)
 create mode 100644 migration/app/proven/ProvenError.affine

diff --git a/migration/app/proven/ProvenError.affine b/migration/app/proven/ProvenError.affine
new file mode 100644
index 00000000..fb596a85
--- /dev/null
+++ b/migration/app/proven/ProvenError.affine
@@ -0,0 +1,59 @@
+// SPDX-License-Identifier: AGPL-3.0-or-later
+// Copyright (c) 2026 Joshua B. Jewell and Jonathan D.A. Jewell
+//
+// ProvenError.affine — error types for proven-safe modules.
+//
+// Translation of src/app/proven/ProvenError.res (32 LoC). Self-contained
+// pure-data + pure-constructors module — no FFI, no cross-module deps,
+// no Tea_/Pixi/Gossamer surface. Cleanest possible Mode-A AffineScript
+// port in idaptik's src/app/ tree.
+//
+// Translation choices:
+//   `type x = { field: T, ... }` → unchanged (no trailing comma).
+//   `let f = (~name: T, ...): U => body` → `fn f(name: T, ...) -> U { body }`
+//     (AS uses positional args, not labelled — the ReScript ~prefix
+//     drops on the call site for `notANumber(operation, message)` etc.).
+//   `{operation, message, errorType}`     → `#{operation: operation, ...}`
+//     punning shorthand drops; AS record literals are explicit.
+//   `` `[${a}] ${b}: ${c}` `` template-literal → `"[" ++ a ++ "] " ++ b ++ ": " ++ c`
+//     AS uses `++` concatenation; template literals are JS-specific.
+//
+// What this PR is NOT
+//   Does NOT replace src/app/proven/ProvenError.res in the build. The .res
+//   still owns the runtime contract — SafeFloat / SafeJson / SafeAngle
+//   reference it directly. Replacement requires the same .affine→.mjs
+//   codegen story tracked under standards#279 STEP 8.
+//
+// Refs: standards#279 (megaport step), standards#252 (campaign umbrella).
+
+module ProvenError;
+
+type ProvenError = {
+  operation: String,
+  message: String,
+  errorType: String,
+}
+
+fn notANumber(operation: String, message: String) -> ProvenError {
+  #{ operation: operation, message: message, errorType: "NaN" }
+}
+
+fn infinity(operation: String, message: String) -> ProvenError {
+  #{ operation: operation, message: message, errorType: "Infinity" }
+}
+
+fn parseFailure(operation: String, message: String) -> ProvenError {
+  #{ operation: operation, message: message, errorType: "ParseFailure" }
+}
+
+fn divisionByZero(operation: String, message: String) -> ProvenError {
+  #{ operation: operation, message: message, errorType: "DivisionByZero" }
+}
+
+fn invalidArgument(operation: String, message: String) -> ProvenError {
+  #{ operation: operation, message: message, errorType: "InvalidArgument" }
+}
+
+fn toString(err: ProvenError) -> String {
+  "[" ++ err.errorType ++ "] " ++ err.operation ++ ": " ++ err.message
+}