fluxconfig: symlinked legacy lib is not "stranded" — realpath-compare in migration

Real-machine transition state: ~/FluxLib stays behind as a symlink to
<FluxConfig>/FluxLib until every old-code session is gone, and old-code
ensureFluxLib re-persists fluxLibPath (recreating the capital config dir) on
every CLI run. The re-merge handled this but logged a misleading "both
libraries exist" warning — now oldLib/target are realpath-compared, so the
symlink case is recognized as already-migrated: key dropped, no warning.
Gate test covers the full old-code-recreation cycle (t6).

Verified on the real machine: recreated ~/.config/Flux re-merged + removed,
prefs back to fluxConfigPath-only, no stranded warning.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: kortdriessen

electron/fluxPaths.cjs

@@ -294,9 +294,19 @@ async function migrateFluxLib(cfg, events) {
   };
   if (fsSync.existsSync(target)) {
     if (oldLib !== target && fsSync.existsSync(oldLib)) {
-      const w = `both ${target} and ${oldLib} exist — leaving both untouched (nothing merged or deleted); resolve by hand`;
-      console.error(`flux config: WARNING — ${w}`);
-      events.push({ action: "stranded-fluxlib-warning", detail: w });
+      // realpath: a transitional symlink (old path -> <cfg>/FluxLib) is the
+      // SAME tree, not a stranded second library — no warning for it.
+      let distinct = true;
+      try {
+        distinct = fsSync.realpathSync(oldLib) !== fsSync.realpathSync(target);
+      } catch {
+        /* unreadable — treat as distinct and warn */
+      }
+      if (distinct) {
+        const w = `both ${target} and ${oldLib} exist — leaving both untouched (nothing merged or deleted); resolve by hand`;
+        console.error(`flux config: WARNING — ${w}`);
+        events.push({ action: "stranded-fluxlib-warning", detail: w });
+      }
     }
     dropKey();
     return;

scripts/verify-fluxconfig.ts

@@ -178,6 +178,24 @@ if (process.platform !== "win32") {
     await fp.ensureFluxConfig();
     assert(fs.existsSync(path.join(f4.home, "FluxConfig", "FluxLib", "library.bib")), "pre-existing empty FluxConfig filled in place");
 
+    // -- transitional symlink (old lib path -> <cfg>/FluxLib) is NOT "stranded"
+    // (the real machine keeps ~/FluxLib as a symlink until every old-code
+    // session is gone; old code re-persists fluxLibPath, so re-merges recur)
+    const f6 = freshFixture("t6");
+    await fp.ensureFluxConfig();
+    fs.symlinkSync(path.join(f6.home, "FluxConfig", "FluxLib"), path.join(f6.home, "FluxLib"));
+    fs.mkdirSync(path.join(f6.xdg, "Flux"), { recursive: true }); // flux-cap-ok (old code recreates it)
+    fs.writeFileSync(
+      path.join(f6.xdg, "Flux", "preferences.json"), // flux-cap-ok
+      JSON.stringify({ schemaVersion: "0.1.0", fluxLibPath: path.join(f6.home, "FluxLib") }),
+    );
+    const r6 = await fp.ensureFluxConfig();
+    assert(r6.fluxLibPath === path.join(f6.home, "FluxConfig", "FluxLib"), "re-merge after old-code prefs recreation resolves derived");
+    const marker6 = JSON.parse(fs.readFileSync(path.join(f6.home, "FluxConfig", ".fluxconfig.json"), "utf8"));
+    assert(!marker6.events.some((e: { action: string }) => e.action === "stranded-fluxlib-warning"), "symlinked legacy lib is not flagged as stranded");
+    const prefs6 = JSON.parse(fs.readFileSync(path.join(f6.xdg, "flux", "preferences.json"), "utf8"));
+    assert(!("fluxLibPath" in prefs6) && prefs6.fluxConfigPath, "re-merge drops the re-persisted fluxLibPath again");
+
     // -- moveFluxConfig (Settings "Move…"): same-fs rename + destination guards
     const f5 = freshFixture("t5");
     await fp.ensureFluxConfig();