deleting a stack shows which folders will be removed, with a choice to keep/delete folders

src/lib/server/stack-delete-guard.ts

@@ -0,0 +1,27 @@
+/**
+ * Pure path guard for stack-directory deletion (#675). Import-light (only node:path), so
+ * it's unit-testable without pulling the DB/docker imports of stacks.ts.
+ *
+ * THE BUG (#675): a stack ADOPTED at the stacks ROOT (compose at
+ * $DATA_DIR/stacks/docker-compose.yml) is auto-named "stacks". On delete, its custom dir
+ * is the stacks ROOT and its basename ("stacks") equals the stack name ("stacks"). A plain
+ * `startsWith(stacksRoot)` guard passed both checks, so rmSync wiped the ENTIRE stacks
+ * folder — every other stack. The fix is a STRICT-subdir check (`startsWith(stacksRoot +
+ * sep)`): resolve() strips trailing separators, so the root has none and fails, while a
+ * real nested stack dir ($DATA_DIR/stacks/<env>/<name>) is a strict subdir and passes.
+ */
+import { resolve, basename, sep as pathSep } from 'node:path';
+
+/**
+ * True when `customDir` is a directory Dockhand may delete for `stackName`: a STRICT
+ * subdirectory of `stacksDir` (never the root itself) whose basename matches the stack
+ * name. Path-only — the caller still checks existsSync before deleting.
+ */
+export function isDeletableStackDir(customDir: string, stacksDir: string, stackName: string): boolean {
+	const resolvedCustomDir = resolve(customDir);
+	const resolvedStacksDir = resolve(stacksDir);
+	return (
+		resolvedCustomDir.startsWith(resolvedStacksDir + pathSep) &&
+		basename(resolvedCustomDir) === stackName
+	);
+}