Collapse whitespace left by stripped filename separators

A real feed titled with pipe separators produced a folder named
"Get in the Trunk  Anthology Series  Delta Green": removing a forbidden
character left the gap around it. Runs of whitespace now collapse, and
control characters map to a space rather than vanishing.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RPyeapneuXrCdojsaiXGbe

PROGRESS.md

@@ -30,6 +30,33 @@ The full design and step list live in the plan file at
 
 ---
 
+## 2026-09-10 — Tested against a real feed (Patreon / Glass Cannon)
+
+First run against a live subscriber feed: 131 items, 6.17 GB total, all `audio/mpeg`, no `<ttl>`.
+Parsed clean, titled `Get in the Trunk | Anthology Series | Delta Green`, downloaded a valid MP3
+(`file` confirms ID3v2.3, MPEG layer III). A second scan pulled the *next* episode, confirming
+`max_new_per_check` defers rather than drops. Over the socket: 101 progress events for a 79 MB
+episode -- whole-percent throttling behaving exactly as intended -- then `download_done`,
+`feed_done`, `scan_done`.
+
+**Fixed: stripped separators left doubled spaces.** The feed title separates words with `|`, a
+forbidden filename character, so the folder came out `Get in the Trunk  Anthology Series  Delta
+Green`. `sanitize()` now collapses runs of whitespace (and maps control characters to a space
+rather than deleting them). The Python had the same wart.
+
+**Worth knowing, not a bug:**
+
+- The channel-level `itunes:explicit` is `true`, so with the default `allow_explicit = false` all
+  131 episodes are skipped. Because filter verdicts are recorded once at discovery, flipping the
+  setting afterwards does not re-evaluate enclosures already marked `skipped` -- they would need a
+  `UPDATE enclosures SET state='pending'`. Worth a `ipx retry <feed>` command if this bites.
+- Patreon sends neither `etag` nor `last-modified` on a GET (a `last-modified` does appear on HEAD,
+  which is what made it look briefly like a storage bug). So this feed can never 304: every poll
+  re-fetches ~160 KB and re-parses 131 entries, and `interval_mins` is the only thing limiting the
+  rate. Cheap, but it means conditional GET buys nothing here.
+
+---
+
 ## 2026-09-09 — Step 8: OPML and polish
 
 `ipx add <url>` fetches the feed to name it from its own title (`Accidental Tech Podcast` ->

src/download.rs

@@ -15,10 +15,24 @@ const MAX_NAME_BYTES: usize = 255;
 /// Keeps UTF-8: the original transliterated to ASCII via latin1_to_ascii because 2004
 /// filesystems demanded it. Ours do not.
 pub fn sanitize(name: &str) -> String {
-    let mut out: String = name
+    let stripped: String = name
         .chars()
-        .filter(|c| !c.is_control() && !FORBIDDEN.contains(c))
+        .map(|c| if c.is_control() { ' ' } else { c })
+        .filter(|c| !FORBIDDEN.contains(c))
         .collect();
+
+    // Stripping a separator leaves a gap: "Show | Series | Delta" would otherwise become
+    // "Show  Series  Delta". Collapse runs of whitespace rather than leaving the seams.
+    let mut out = String::with_capacity(stripped.len());
+    for c in stripped.chars() {
+        if c.is_whitespace() {
+            if !out.ends_with(' ') {
+                out.push(' ');
+            }
+        } else {
+            out.push(c);
+        }
+    }
     out = out.trim().trim_matches('.').trim().to_owned();
 
     if out.len() > MAX_NAME_BYTES {
@@ -266,10 +280,21 @@ mod tests {
     fn sanitize_strips_path_and_control_characters() {
         assert_eq!(sanitize("../../etc/passwd"), "etcpasswd");
         assert_eq!(sanitize("Ep 12: The \"Best\" One?"), "Ep 12 The Best One");
-        assert_eq!(sanitize("bad\u{0}name\u{7}.mp3"), "badname.mp3");
+        assert_eq!(sanitize("bad\u{0}name\u{7}.mp3"), "bad name .mp3");
         assert_eq!(sanitize("  spaced.mp3  "), "spaced.mp3");
     }
 
+    #[test]
+    fn sanitize_collapses_the_gaps_left_by_stripped_separators() {
+        // A real Patreon feed title; the pipes are forbidden characters.
+        assert_eq!(
+            sanitize("Get in the Trunk | Anthology Series | Delta Green"),
+            "Get in the Trunk Anthology Series Delta Green"
+        );
+        assert_eq!(sanitize("Ep 12: The One"), "Ep 12 The One");
+        assert_eq!(sanitize("a   b"), "a b");
+    }
+
     #[test]
     fn sanitize_never_yields_an_empty_or_dot_name() {
         assert_eq!(sanitize(""), "download");