fix: finalize structured output only on success; docs facelift + em-dash normalize

Code:
- main.go: move out.Finish() off defer to just before the success "return 0".
  Previously the deferred finalizer ran on every exit path, so an early error
  (e.g. wildcard detection without -force) emitted an empty JSON array in
  -format json. Text mode is unchanged (Finish is a no-op for text). The file
  flush/close defer still runs after Finish, so buffered JSON/CSV is persisted
  before the file closes.
- internal/output: add TestWriterJSONFinishGatesOutput documenting that
  structured output is emitted only by Finish (no Finish = no spurious array).

Docs:
- docs/index.md: refreshed to the 0.6.0 feature set with cards for Output
  Formats (-format), Rate Limiting (-rate), Record Types (-type), and Recursive
  Enumeration (-recursive/-depth), matching the README Feature Matrix.
- Normalized em dashes to hyphens across docs/ (index, ARCHITECTURE,
  DEVELOPER_GUIDE, _config.yml, default.html). Arrows and code identifiers
  left intact; changelog history untouched.

Logged under CHANGELOG [Unreleased].

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: TMHSDigital

CHANGELOG.md

@@ -5,6 +5,15 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Fixed
+- Structured output (`-format json` and `-format csv`) is now finalized only on the successful scan path. The finalizer previously ran via `defer` on every exit, so an early error (such as wildcard detection without `-force`) emitted an empty JSON array. Text output behavior is unchanged.
+
+### Docs
+- GitHub Pages landing page (`docs/index.md`) refreshed to the 0.6.0 feature set, adding cards for Output Formats (`-format`), Rate Limiting (`-rate`), Record Types (`-type`), and Recursive Enumeration (`-recursive`/`-depth`).
+- Normalized em dashes to hyphens across `docs/` for consistency with the no-em-dash convention.
+
 ## [0.6.0] - 2026-06-03
 
 ### Added

docs/ARCHITECTURE.md

@@ -23,16 +23,16 @@ This architecture is designed to be efficient by performing multiple DNS lookups
 ### Package Structure
 
 ```
-main.go                        — CLI entry point (flag parsing, wiring, -tui dispatch)
-internal/scan/runner.go        — Scan engine: Config, Event types, Run(ctx, cfg, events)
-internal/dns/resolver.go       — ResolveDomain, ResolveDomainWithRetry, CheckWildcard
-internal/dns/simulate.go       — SimulateResolution
-internal/output/writer.go      — Thread-safe Writer (results→stdout, diagnostics→stderr)
-internal/wordlist/reader.go    — LoadWordlist (dedup + sanitize)
-internal/tui/model.go          — Root Bubble Tea model (form → scan state machine)
-internal/tui/form.go           — Config form screen (textinput fields + toggles)
-internal/tui/scan_view.go      — Live results screen (viewport + progress bar)
-internal/tui/config.go         — Session persistence (load/save ~/.config/subenum/last.json)
+main.go                        - CLI entry point (flag parsing, wiring, -tui dispatch)
+internal/scan/runner.go        - Scan engine: Config, Event types, Run(ctx, cfg, events)
+internal/dns/resolver.go       - ResolveDomain, ResolveDomainWithRetry, CheckWildcard
+internal/dns/simulate.go       - SimulateResolution
+internal/output/writer.go      - Thread-safe Writer (results→stdout, diagnostics→stderr)
+internal/wordlist/reader.go    - LoadWordlist (dedup + sanitize)
+internal/tui/model.go          - Root Bubble Tea model (form → scan state machine)
+internal/tui/form.go           - Config form screen (textinput fields + toggles)
+internal/tui/scan_view.go      - Live results screen (viewport + progress bar)
+internal/tui/config.go         - Session persistence (load/save ~/.config/subenum/last.json)
 ```
 
 ## 2. Key Components / Modules
@@ -71,7 +71,7 @@ internal/tui/config.go         — Session persistence (load/save ~/.config/sube
     *   Function: `dns.Resolve(ctx, domain, timeout, dnsServer) ([]Record, time.Duration, error)` and `dns.ResolveTypes(..., types)` - perform the lookups and return typed `Record{Type, Value}` results. `ResolveTypes` issues per-type lookups (`LookupIP` ip4/ip6 for A/AAAA, `LookupCNAME` for CNAME) and filters to the requested types (default A,AAAA via `-type`).
     *   Function: `dns.ResolveDomain(ctx, domain, timeout, dnsServer, verbose) bool` - convenience wrapper returning a boolean, used by wildcard detection.
     *   Function: `dns.ResolveDomainWithRetry(ctx, domain, timeout, dnsServer, verbose, maxAttempts, types) ([]Record, bool)` - wraps the lookup with configurable retry logic and linear backoff between attempts, returning the resolved records.
-    *   Function: `dns.CheckWildcard(ctx, domain, timeout, dnsServer) (bool, error)` — resolves two random subdomains to detect wildcard DNS records.
+    *   Function: `dns.CheckWildcard(ctx, domain, timeout, dnsServer) (bool, error)` - resolves two random subdomains to detect wildcard DNS records.
     *   `net.Resolver{}`: A custom DNS resolver is configured.
         *   `PreferGo: true`: Instructs the resolver to use the pure Go DNS client.
         *   `Dial func(ctx context.Context, network, address string) (net.Conn, error)`: A custom dial function is provided to control the connection to the DNS server, using the user-specified `dnsServer` address.
@@ -86,7 +86,7 @@ internal/tui/config.go         — Session persistence (load/save ~/.config/sube
 *   **Purpose**: To efficiently perform DNS lookups for a large number of potential subdomains, `subenum` employs a worker pool pattern. This allows multiple DNS queries to be in flight concurrently, significantly speeding up the enumeration process compared to sequential lookups.
 *   **Implementation**: The worker pool logic lives in `internal/scan/runner.go` as `scan.Run(ctx, cfg, events)`. Both the CLI (`run()` in `main.go`) and the TUI (`internal/tui`) call this function.
     *   **`scan.Config`**: A struct carrying all scan parameters (domain, entries slice, concurrency, timeout, DNS server, simulate flag, etc.).
-    *   **`scan.Event` / `scan.EventKind`**: Typed events emitted on a `chan<- scan.Event` — `EventResult`, `EventProgress`, `EventWildcard`, `EventError`, `EventDone`.
+    *   **`scan.Event` / `scan.EventKind`**: Typed events emitted on a `chan<- scan.Event` - `EventResult`, `EventProgress`, `EventWildcard`, `EventError`, `EventDone`.
     *   **Dispatcher and work queue**: A dispatcher goroutine owns an internal `jobs` channel, the queue of pending `job{domain, depth}` items, a visited set, and a pending-work counter. It seeds the queue from the wordlist slice and feeds workers. Workers submit newly discovered children back to the dispatcher over an `enqueue` channel and signal each finished job over a `completed` channel. The dispatcher closes `jobs` only when the pending counter reaches zero (or the context is cancelled). This lifecycle lets resolved subdomains enqueue children safely (recursive mode) without risking a send on a closed channel.
     *   **`var wg sync.WaitGroup`**: A `sync.WaitGroup` waits for all worker goroutines to finish.
     *   **Worker Goroutines Loop**: `cfg.Concurrency` goroutines are launched. Each reads a job from `jobs`, constructs nothing further (the job already holds the full domain), and calls `dns.ResolveDomainWithRetry()` (or `dns.SimulateResolve()` in simulate mode).
@@ -102,11 +102,11 @@ internal/tui/config.go         — Session persistence (load/save ~/.config/sube
 *   **Implementation**:
     *   `output.Writer` struct with mutex-protected methods:
         *   `Result(domain, records)` - in `text` format prints `Found: <domain>` to stdout (and the output file if configured); in `json` format buffers `{"subdomain", "records"}` objects and writes a single array at completion; in `csv` format streams `subdomain,type,value` rows with a header. The format is selected with `-format text|json|csv` (default `text`, which is byte-for-byte identical to prior behavior). The JSON array is buffered because it is a single document and does not stream; JSONL would be the streaming-friendly alternative if needed. Output formats are CLI-only for now (TUI-pending).
-        *   `Progress(pct, processed, total, found)` — writes a carriage-return progress line to stderr.
-        *   `Info(format, args...)` — writes an informational line to stderr.
-        *   `Error(format, args...)` — writes an error line to stderr.
+        *   `Progress(pct, processed, total, found)` - writes a carriage-return progress line to stderr.
+        *   `Info(format, args...)` - writes an informational line to stderr.
+        *   `Error(format, args...)` - writes an error line to stderr.
     *   **Verbose Output** (when `-v` flag is enabled):
-        *   Configuration summary, per-query DNS resolution info, and final scan statistics — all via `Info` to stderr.
+        *   Configuration summary, per-query DNS resolution info, and final scan statistics - all via `Info` to stderr.
     *   **Progress Reporting** (when `-progress` flag is enabled):
         *   A dedicated goroutine using a 1-second ticker calls `Progress` on stderr.
 *   **Interactions**: All components route output through the `Writer`. Since results are the only thing on stdout, piping (`| cut -d' ' -f2`) works without `-progress=false`.
@@ -130,9 +130,9 @@ internal/tui/config.go         — Session persistence (load/save ~/.config/sube
 *   **Purpose**: Remember the last-used TUI form values across sessions so users don't have to re-type domain, wordlist path, and scan parameters every time.
 *   **Implementation**:
     *   `savedConfig` struct mirrors `formValues` with JSON tags.
-    *   `configPath()` — returns `os.UserConfigDir()/subenum/last.json` (e.g. `~/.config/subenum/last.json` on Linux/macOS, `%AppData%\subenum\last.json` on Windows).
-    *   `saveConfig(fv formValues) error` — marshals `formValues` to JSON and writes it atomically with `os.WriteFile`. Called in `beginScan()` immediately before launching the scan goroutine. Errors are silently discarded so a write failure never blocks the scan.
-    *   `loadSavedConfig() (savedConfig, bool)` — reads and unmarshals the file. Returns `false` if the file doesn't exist or is unreadable, causing `newFormModel` to fall back to hardcoded defaults.
+    *   `configPath()` - returns `os.UserConfigDir()/subenum/last.json` (e.g. `~/.config/subenum/last.json` on Linux/macOS, `%AppData%\subenum\last.json` on Windows).
+    *   `saveConfig(fv formValues) error` - marshals `formValues` to JSON and writes it atomically with `os.WriteFile`. Called in `beginScan()` immediately before launching the scan goroutine. Errors are silently discarded so a write failure never blocks the scan.
+    *   `loadSavedConfig() (savedConfig, bool)` - reads and unmarshals the file. Returns `false` if the file doesn't exist or is unreadable, causing `newFormModel` to fall back to hardcoded defaults.
 *   **Interactions**: `tui.New()` calls `loadSavedConfig()` on startup and passes the result to `newFormModel`. The `r` keybind (new scan) also calls `loadSavedConfig()` so the form is pre-filled with the values from the scan that just completed.
 
 ## 3. Data Flow

docs/DEVELOPER_GUIDE.md

@@ -242,8 +242,8 @@ Please follow these style guidelines when contributing:
 
 The CLI path (`run()`) has zero external dependencies. The TUI path (`-tui` flag) adds:
 
-- [`github.com/charmbracelet/bubbletea`](https://github.com/charmbracelet/bubbletea) — Elm-architecture terminal UI framework
-- [`github.com/charmbracelet/bubbles`](https://github.com/charmbracelet/bubbles) — reusable TUI components (textinput, viewport, progress bar)
+- [`github.com/charmbracelet/bubbletea`](https://github.com/charmbracelet/bubbletea) - Elm-architecture terminal UI framework
+- [`github.com/charmbracelet/bubbles`](https://github.com/charmbracelet/bubbles) - reusable TUI components (textinput, viewport, progress bar)
 
 If you need to add a further dependency:
 
@@ -258,7 +258,7 @@ If you need to add a further dependency:
 
 Areas for potential enhancement include:
 
-*   **Terminal UI**: An interactive TUI (`-tui` flag) built with Bubble Tea. Provides a form-based config screen and a live-scrolling results view — no arguments required to launch. Last-used values persist to `~/.config/subenum/last.json` across sessions.
+*   **Terminal UI**: An interactive TUI (`-tui` flag) built with Bubble Tea. Provides a form-based config screen and a live-scrolling results view - no arguments required to launch. Last-used values persist to `~/.config/subenum/last.json` across sessions.
 *   **Output Formats**: Supporting different output formats (JSON, CSV) in addition to the current plain text output file (`-o`).
 *   **Result Filtering**: Allowing users to filter results based on DNS record types.
 *   **Recursive Enumeration**: Adding support for recursive subdomain enumeration (e.g., finding subdomains of discovered subdomains).

docs/_config.yml

@@ -1,6 +1,6 @@
 theme: jekyll-theme-cayman
 title: subenum
-description: Fast, concurrent subdomain enumeration via DNS brute-forcing — written in pure Go.
+description: Fast, concurrent subdomain enumeration via DNS brute-forcing - written in pure Go.
 show_downloads: false
 url: "https://tmhsdigital.github.io"
 baseurl: "/subenum"

docs/_layouts/default.html

@@ -4,7 +4,7 @@
     <meta charset="UTF-8">
     <meta http-equiv="X-UA-Compatible" content="IE=edge">
     <meta name="viewport" content="width=device-width, initial-scale=1">
-    <title>{% if page.title == "Home" %}{{ site.title }} — {{ site.description }}{% else %}{{ page.title }} — {{ site.title }}{% endif %}</title>
+    <title>{% if page.title == "Home" %}{{ site.title }} - {{ site.description }}{% else %}{{ page.title }} - {{ site.title }}{% endif %}</title>
     <link rel="stylesheet" href="{{ '/assets/css/style.css?v=' | append: site.github.build_revision | relative_url }}">
     <style>
       /* ── Nav bar ── */
@@ -58,7 +58,7 @@
         padding: 5rem 2rem 4rem;
         background: linear-gradient(160deg, #0d1117 0%, #161b22 60%, #1a2332 100%);
       }
-      /* Hide Cayman's default title/tagline — we render our own */
+      /* Hide Cayman's default title/tagline - we render our own */
       .page-header .project-name,
       .page-header .project-tagline { display: none; }
 
@@ -137,7 +137,7 @@
         margin: 1rem 0;
       }
       .main-content blockquote p { margin: 0; color: #57606a; }
-      /* Links — restore blue on top of the * reset */
+      /* Links - restore blue on top of the * reset */
       .main-content a { color: #0969da !important; }
       .main-content a:hover { text-decoration: underline; }
       /* Inline code */
@@ -148,7 +148,7 @@
         padding: 1px 5px;
         font-size: 0.88em;
       }
-      /* Block code — distinct background from page */
+      /* Block code - distinct background from page */
       .main-content pre {
         background: #f0f2f5;
         border: 1px solid #d0d7de;

docs/index.md

@@ -9,12 +9,12 @@ title: Home
 
 ## What it does
 
-subenum brute-forces subdomains by resolving a wordlist against a target domain using a concurrent worker pool. Results stream to stdout — pipe-clean, no noise. Everything else (progress, diagnostics, errors) goes to stderr.
+subenum brute-forces subdomains by resolving a wordlist against a target domain using a concurrent worker pool. Results stream to stdout - pipe-clean, no noise. Everything else (progress, diagnostics, errors) goes to stderr.
 
 <div class="screenshot-wrap">
   <figure>
-    <img src="assets/tui-form.png" alt="subenum TUI — Configure Scan">
-    <figcaption>Interactive TUI — launch with <code>./subenum -tui</code> or <code>make tui</code></figcaption>
+    <img src="assets/tui-form.png" alt="subenum TUI - Configure Scan">
+    <figcaption>Interactive TUI - launch with <code>./subenum -tui</code> or <code>make tui</code></figcaption>
   </figure>
 </div>
 
@@ -37,7 +37,23 @@ subenum brute-forces subdomains by resolving a wordlist against a target domain
   </div>
   <div class="feature-card">
     <strong>Simulation Mode</strong>
-    <span>Generate synthetic DNS results at a configurable hit rate — zero network I/O. Safe for demos and testing.</span>
+    <span>Generate synthetic DNS results at a configurable hit rate - zero network I/O. Safe for demos and testing.</span>
+  </div>
+  <div class="feature-card">
+    <strong>Output Formats</strong>
+    <span>Emit results as <code>text</code>, <code>json</code> (array of subdomain plus typed records), or <code>csv</code> via <code>-format</code>.</span>
+  </div>
+  <div class="feature-card">
+    <strong>Rate Limiting</strong>
+    <span>Cap total DNS queries per second across the worker pool with <code>-rate</code> (context-aware, stays responsive to Ctrl+C).</span>
+  </div>
+  <div class="feature-card">
+    <strong>Record Types</strong>
+    <span>Look up and filter by <code>A</code>, <code>AAAA</code>, or <code>CNAME</code> records with <code>-type</code>.</span>
+  </div>
+  <div class="feature-card">
+    <strong>Recursive Enumeration</strong>
+    <span>Enumerate subdomains of discovered subdomains with <code>-recursive</code> and a <code>-depth</code> cap, with loop and duplicate protection.</span>
   </div>
   <div class="feature-card">
     <strong>Pipe-Friendly Output</strong>

internal/output/writer_test.go

@@ -100,6 +100,62 @@ func TestWriterResultJSONFile(t *testing.T) {
 	}
 }
 
+// TestWriterJSONFinishGatesOutput locks in the contract main.run relies on:
+// structured output is emitted only by Finish, so skipping Finish on an error
+// path produces no spurious empty JSON array.
+func TestWriterJSONFinishGatesOutput(t *testing.T) {
+	// Error path: results buffered (or none) but Finish never called.
+	noFinish, err := os.CreateTemp("", "output-json-nofinish-*.json")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer func() { _ = os.Remove(noFinish.Name()) }()
+
+	bw := bufio.NewWriter(noFinish)
+	_ = New(bw, false, FormatJSON)
+	if err := bw.Flush(); err != nil {
+		t.Fatal(err)
+	}
+	if err := noFinish.Close(); err != nil {
+		t.Fatal(err)
+	}
+	content, err := os.ReadFile(noFinish.Name())
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(content) != 0 {
+		t.Errorf("expected no structured output without Finish, got:\n%s", content)
+	}
+
+	// Success path: Finish with zero results emits an empty JSON array.
+	withFinish, err := os.CreateTemp("", "output-json-finish-*.json")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer func() { _ = os.Remove(withFinish.Name()) }()
+
+	bw2 := bufio.NewWriter(withFinish)
+	w := New(bw2, false, FormatJSON)
+	w.Finish()
+	if err := bw2.Flush(); err != nil {
+		t.Fatal(err)
+	}
+	if err := withFinish.Close(); err != nil {
+		t.Fatal(err)
+	}
+	content, err = os.ReadFile(withFinish.Name())
+	if err != nil {
+		t.Fatal(err)
+	}
+	var results []Result
+	if err := json.Unmarshal(content, &results); err != nil {
+		t.Fatalf("Finish output is not a valid JSON array: %v\nGot:\n%s", err, content)
+	}
+	if len(results) != 0 {
+		t.Errorf("expected empty array from Finish with no results, got %d", len(results))
+	}
+}
+
 func TestWriterResultCSVFile(t *testing.T) {
 	tmp, err := os.CreateTemp("", "output-csv-*.csv")
 	if err != nil {

main.go

@@ -285,10 +285,6 @@ func run() int {
 			}
 		}()
 	}
-	// Finish runs before the file flush/close defer above (LIFO), so buffered
-	// JSON and streamed CSV are written before the file is closed.
-	defer out.Finish()
-
 	if f.verbose {
 		logVerboseStart(f, domain, maxAttempts, out)
 	}
@@ -370,6 +366,11 @@ func run() int {
 			}
 		}
 	}
+	// Finalize structured output only on the success path, so an early error
+	// (such as wildcard detection without -force) does not emit an empty JSON
+	// array or a bare CSV header. The deferred file flush/close registered
+	// above runs after this, persisting buffered output before the file closes.
+	out.Finish()
 	return 0
 }