fix(test): canonicalize temp paths so imagine dryRun perFile passes on macOS (symlinked tmpdir)

dryRun() attributes test failures to files by string-matching node --test's
`location:` diagnostic (a canonical realpath) against join(wt, testfile). On
macOS the sandbox worktree lives under tmpdir(), which is itself a symlink
(/var → /private/var, /tmp → /private/tmp), so the raw wt path never matched
the realpath'd locations: attribution failed, perFile was omitted, and
test/imagine.test.js "dryRun executes the suite in an ephemeral worktree and
removes it (pass + fail)" saw perFile === undefined instead of the expected
{ "test/pass.test.js": "pass", "test/fail.test.js": "fail" }.

Fix the code (not the test): realpathSync(wt) once after the worktree is
created and compare against that canonical root. On Linux (no symlinked tmpdir)
this is a no-op. Re-enable the full unit suite on macos-latest in smoke.yml.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KfCEnSJzSG914yyVesjjD6

Author: claude

.github/workflows/smoke.yml

@@ -42,13 +42,9 @@ jobs:
       - name: Install/uninstall smoke (isolated HOME)
         shell: bash
         run: bash scripts/smoke-install.sh
-      # Re-run the unit suite here only on Linux — ci.yml already runs it on the Node 20/22
-      # Linux matrix, so this is just belt-and-suspenders on the same platform.
-      # TODO(macos-suite): the first macOS run surfaced ONE environment-specific unit-test
-      # failure (the install smoke itself is green on macOS; only a temp-path/case-sensitivity
-      # assumption in a unit test trips on APFS + /tmp→/private/tmp). Pin and fix that test,
-      # then drop this `if` to get full macOS unit coverage. The install evidence — P2's
-      # actual deliverable — already runs on macos above.
+      # Re-run the unit suite here across the matrix. ci.yml already runs it on the Node
+      # 20/22 Linux matrix; running it on macOS too proves the >=20 behavior on APFS +
+      # /tmp→/private/tmp, where tmpdir() is a symlink (dryRun now canonicalizes worktree
+      # paths so per-file attribution string-matches node --test's realpath'd locations).
       - name: Test suite
-        if: matrix.os == 'ubuntu-latest'
         run: npm test

CHANGELOG.md

@@ -6,6 +6,16 @@ to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
 
+### Fixed
+
+- **`forge imagine --dry-run` per-file attribution on macOS.** `dryRun()` matched node
+  `--test`'s realpath'd `location:` diagnostics against a raw `mkdtemp` worktree path; on
+  platforms where `tmpdir()` is itself a symlink (macOS: `/var`→`/private/var`,
+  `/tmp`→`/private/tmp`) the two never matched, so the pass/fail-per-file breakdown was
+  silently dropped. The worktree root is now canonicalized with `realpathSync` before
+  comparison (a no-op on Linux). The CI smoke matrix now runs the full unit suite on
+  `macos-latest`, which surfaced this.
+
 ## [0.23.0] - 2026-07-19
 
 ### Security

src/imagine.js

@@ -8,7 +8,7 @@
 // TAP summary, and always discards the sandbox. Selection stays useful on its own as
 // "run these, in this order"; dryRun turns the prediction into measured evidence.
 import { execFileSync, spawnSync } from "node:child_process";
-import { existsSync, mkdtempSync, readFileSync, rmSync, statSync } from "node:fs";
+import { existsSync, mkdtempSync, readFileSync, realpathSync, rmSync, statSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 import { build as buildAtlas, impact, load as loadAtlas } from "./atlas.js";
@@ -134,6 +134,12 @@ export function dryRun(root, { tests, timeoutMs = 120000 } = {}) {
       const msg = /** @type {{stderr?: Buffer}} */ (e).stderr?.toString().trim() || String(e);
       return { ok: false, reason: `git worktree add failed: ${msg}` };
     }
+    // node --test reports each failure's `location:` as a canonical (realpath'd) path.
+    // On platforms where tmpdir() itself is a symlink (macOS: /var → /private/var), the
+    // raw `wt` path won't string-match those locations, so per-file attribution below
+    // must compare against the canonicalized worktree root. On Linux (no symlink) this
+    // is a no-op.
+    const wtReal = realpathSync(wt);
     // Runner policy: always `node --test <files...>` — a custom package test script
     // (jest, vitest, …) is a WHOLE-SUITE command that can't be scoped per-file safely,
     // which would defeat minimal selection. We still run node --test and say so, so a
@@ -196,7 +202,7 @@ export function dryRun(root, { tests, timeoutMs = 120000 } = {}) {
     let attributable = true;
     for (const block of (run.stdout ?? "").split(/^not ok /m).slice(1)) {
       const file = block.split("\n").map(locFile).find(Boolean);
-      const t = file && tests.find((c) => file === join(wt, String(c)));
+      const t = file && tests.find((c) => file === join(wtReal, String(c)));
       if (t) perFile[String(t)] = "fail";
       else attributable = false;
     }