Summary

Two bugs combined to produce undismissable duplicate project entries in the sidebar (#38). PR #37 partially addressed this for Windows drive paths; this PR fixes the root cause for all platforms by matching Claude CLI's encoding algorithm exactly.

Bug 1 — folder-name encoding mismatch

Switchboard's regex replace(/[/_]/g, '-') only handled / and _. The Claude CLI normalizes every non-alphanumeric character and applies a 200-character cap with a deterministic hash suffix on overflow. So any path containing spaces, dots, backslashes (Windows), colons (Windows drive letters), or parentheses produced two different folder names — Switchboard's seed folder, and the CLI's actual session folder — both surfacing as the same project in the sidebar.

Reverse-engineered the CLI's algorithm from claude 2.1.126:

function encodeProjectPath(p) {
  const s = p.replace(/[^a-zA-Z0-9]/g, '-');
  if (s.length <= 200) return s;
  let h = 0;
  for (let i = 0; i < p.length; i++) h = (h << 5) - h + p.charCodeAt(i) | 0;
  return s.slice(0, 200) + '-' + Math.abs(h).toString(36);
}

The hash is a Java-style String.hashCode truncated to int32. Pure and deterministic, so Switchboard now produces byte-identical folder names to the CLI for any project path.

Bug 2 — phantom projects from archive filter ordering

In session-cache.js:buildProjectsFromCache, the project entry was added to projectMap before the if (!showArchived && s.archived) continue filter ran. Folders whose sessions were all archived ended up as empty { sessions: [] } entries in the sidebar, and the archive button's if (sessions.length === 0) return made them undismissable. Fix: only insert into projectMap after the filter passes.

Changes

• New encode-project-path.js — single source of truth for the encoder (main process)
• Mirror of the same function in public/utils.js for the renderer
• All 10 call sites across main.js, session-cache.js, schedule-ipc.js, public/app.js, public/dialogs.js now use encodeProjectPath()
• session-cache.js archive-filter ordering fix

Migration note

Existing duplicate folders on disk from before this fix are left alone — auto-cleanup felt risky. Users with pre-existing dupes can rm -rf ~/.claude/projects/<bad-folder-name> manually. New projects added after this fix will encode correctly and merge with whatever the CLI creates.

Relationship to #37

#37 widened the regex to [\\/:_] to cover Windows drive paths. This PR subsumes that fix — [^a-zA-Z0-9] covers \ and : and everything else, and adds the missing 200-char cap + hash suffix branch. Recommend closing #37 in favor of this.

Test plan

• macOS: add a project with spaces in the path (e.g. /Users/you/My Project) → folder created as -Users-you-My-Project, matches CLI when claude is run there
• macOS: project path with dots (e.g. msci-6.1-upgrade) → encodes consistently with CLI
• Windows: add a project on a non-C drive (e.g. Q:\src\DevBox) → folder created as Q--src-DevBox, no ENOENT
• Archive every session in a project → project disappears from sidebar (no phantom entry)
• Toggle "show archived" → archived-only projects reappear
• Empty project directory (no sessions in DB) still appears in sidebar (regression check on the empty-dirs pass)

Fixes #38.