Remove the cache epoch

CHANGELOG.md

@@ -14,7 +14,7 @@
 
 ### Fixed
 
-- **Diff display config no longer changes what Worktrunk reads**: `color.ui = always` and `diff.external` reached the commit, squash, and summary prompts. Two settings could also hide a branch's changes from the integration check, so `wt remove` deleted the branch without `-D`: `diff.relative` when run from a subdirectory the changes sat outside, and `submodule.<name>.ignore` on a submodule bump. Every diff Worktrunk parses now runs plumbing, which ignores that configuration, and upgrading discards the cached answers. ([#4146](https://github.com/max-sixty/worktrunk/pull/4146), [#4147](https://github.com/max-sixty/worktrunk/pull/4147), [#4181](https://github.com/max-sixty/worktrunk/pull/4181))
+- **Diff display config no longer changes what Worktrunk reads**: `color.ui = always` and `diff.external` reached the commit, squash, and summary prompts. Two settings could also hide a branch's changes from the integration check, so `wt remove` deleted the branch without `-D`: `diff.relative` when run from a subdirectory the changes sat outside, and `submodule.<name>.ignore` on a submodule bump. Every diff Worktrunk parses now runs plumbing, which ignores that configuration. The integration check caches its answer keyed on the branch and target tips, with no expiry, so an answer an earlier version got wrong is still on disk — if either setting is in your git config, run `wt config state cache clear` once to drop it. ([#4146](https://github.com/max-sixty/worktrunk/pull/4146), [#4147](https://github.com/max-sixty/worktrunk/pull/4147))
 
 - **`wt config update --output <path>` asks before overwriting**: it replaced whatever was there, so `--output ~/.config/worktrunk/config.toml` from a repo with a deprecated project config wiped the user config and reported success. It now prompts, takes `--yes`, and refuses the config being migrated. (Breaking: `--output` naming the config being migrated used to succeed unless the migration dropped `approved-commands`.) ([#4153](https://github.com/max-sixty/worktrunk/pull/4153))
 

CLAUDE.md

@@ -243,7 +243,7 @@ No `get_*` — bare nouns follow Rust stdlib convention.
 
 `Repository` caches read-only values via `Arc<RepoCache>` (cloning shares it). What is and isn't cached, the `list_worktrees()` post-mutation invariant, the two storage patterns, and the in-memory-`RepoCache`-vs-persistent-`sha_cache` decision (cheap-and-hot → in-memory get-or-create; expensive → disk; both → in-memory front over disk back): the `# Caching` section in `src/git/repository/mod.rs`.
 
-**A change to what a cached value means bumps `CACHE_EPOCH`** (`src/cache.rs`). The persistent entries are keyed on SHA pairs with no TTL, so the key cannot see the generator's output: an entry written by an older `wt` keeps answering until its key recurs, and on a finished branch that is never. Moving the diffs onto plumbing is the worked example — it left `has-added-changes` entries saying an unmerged branch had no added changes, which is `wt remove` deleting it. So the question belongs to any change that alters what a cached read reports, not just to code inside `cache.rs`; ask it whenever a generator behind one of `sha_cache`'s kinds changes.
+**A change to what a cached value means leaves the old answers in place.** The persistent entries are keyed on SHA pairs with no TTL, so the key cannot see the generator's output: an entry written by an older `wt` keeps answering until its key recurs, and on a finished branch that is never. Moving the diffs onto plumbing is the worked example — it left `has-added-changes` entries saying an unmerged branch had no added changes, which is `wt remove` deleting it. Nothing invalidates these on an upgrade, and that's the decision rather than an omission: a cache version — a stamp, or a version segment in the path — is permanent machinery for a transition that has come up once, so the remediation goes in the changelog instead. An entry that changes what a cached read reports says what the old answers get wrong and that `wt config state cache clear` drops them. Ask whenever a generator behind one of `sha_cache`'s kinds changes, not only for code inside `cache.rs`.
 
 ## Releases
 

docs/src/content/docs/faq.md

@@ -138,7 +138,7 @@ Worktrunk stores repository state, caches, and logs under `.git/`:
 | Location | Purpose | Created by |
 |----------|---------|------------|
 | `git config worktrunk.*` | Cached default branch, switch history, branch markers, custom variables | Various commands |
-| `.git/wt/cache/{kind}/*.json` | Cached CI status, the largest PR/MR number seen (sizes the `wt list` CI column), and git command results (merge-tree, integration probes, diff stats, ancestry checks, ahead/behind counts, merge bases), beside a stamp of what those results mean — a worktrunk that disagrees with it discards the tree | `wt list`, `wt merge`, `wt remove` |
+| `.git/wt/cache/{kind}/*.json` | Cached CI status, the largest PR/MR number seen (sizes the `wt list` CI column), and git command results (merge-tree, integration probes, diff stats, ancestry checks, ahead/behind counts, merge bases) | `wt list`, `wt merge`, `wt remove` |
 | `.git/wt/cache/summary/{branch}/{hash}.json` | Cached LLM branch summaries, content-addressed by diff hash | `wt list --full`, `wt switch` (when `[list] summary = true`) |
 | `.git/wt/cache/picker-preview/*.json` | Rendered preview panes for the interactive picker | `wt switch` |
 | `.git/wt/logs/{branch}/**/*.log` | Background hook output (nested per branch) | Hooks, background `wt remove` |
@@ -213,7 +213,6 @@ A branch checked out in a second worktree is retained regardless, `-D` included.
 
 - `wt merge` / `wt step push` — the target branch's checked-out worktree is updated to the merged commits, so a file those commits delete disappears from it, and an ignored file at a path they track is overwritten — the same result a `git merge` run in that worktree would produce. Uncommitted changes at paths the merge doesn't touch stay in place, staged or not; one at a path it does touch refuses the merge upfront, naming the file
 - `wt remove` — also stops the removed worktree's `git fsmonitor--daemon` (under `core.fsmonitor=true`), and sweeps `.git/wt/trash/` entries older than 24 hours along with fsmonitor daemons whose worktree no longer exists
-- any command reading a cache — discards the cached git-command results under `.git/wt/cache/` when they were written by a worktrunk that computed them differently, so a stale answer can't outlive the code that produced it. Cached CI status and LLM summaries are keyed on what they describe, so they are left alone
 - `wt config state clear` — removes all worktrunk data from `.git/` (config keys, caches, markers, hints, variables, logs, stale trash)
 - `wt config shell install` — replaces an existing fish or Nushell wrapper file whole, and removes one an older version installed at a previous location (fish `conf.d/wt.fish`, Nushell `<config-dir>/vendor/autoload/wt.nu`), printing each removal; [Files created](/shell-integration/#files-created) names the file each shell gets
 - `wt config shell uninstall` — removes the lines that run `wt config shell init` from bash/zsh/PowerShell rc files, and deletes wrapper and completion files carrying worktrunk's content markers (fish `functions/`, `conf.d/`, and `completions/`; nushell `vendor/autoload`). Every removed line is printed