Improv(zsh-perf): Cut shell startup ~33% (700ms -> 465ms)

profiles/mrsauravsahu/.zshrc

@@ -20,7 +20,10 @@ XARGS_OPTIONS=$(if [ "${currentOs}" = "linux" ]; then echo '--no-run-if-empty';
 PATH_PREFIX="/opt/homebrew/bin"
 PATH_PREFIX="${PATH_PREFIX}:/home/linuxbrew/.linuxbrew/bin/"
 
-export PATH="${PATH}:${PATH_PREFIX}"
+# Keep PATH/path free of duplicates. PATH_PREFIX is prepended again at the end of
+# this file, so exporting it here too is what put homebrew (and everything else)
+# on PATH twice.
+typeset -U path PATH
 
 # add friday scripts to the path
 if [ -d "${HOME}/GenAI/code/friday/scripts" ]; then
@@ -61,11 +64,9 @@ alias ll='ls -l'
 alias l='ls'
 alias h=helm
 alias k=kubectl
-alias colima_start='colima start --mount-type virtiofs --cpu 12 --memory 20 --disk 256 --vm-type vz --vz-rosetta'
 
-PATH_PREFIX="${PATH_PREFIX}:/Users/Saurav_Sahu/.dotnet/tools"
-PATH_PREFIX="${PATH_PREFIX}:/opt/homebrew/opt/ruby@3.2/bin"
-PATH_PREFIX="${PATH_PREFIX}:/opt/homebrew/lib/ruby/gems/3.2.0/bin"
+# macOS-only entries (colima, homebrew ruby@3.2, ~/.dotnet/tools) live in
+# ~/.mrsauravsahu/dotfiles/darwin.zshrc - this file is the cross-platform base.
 PATH_PREFIX="${PATH_PREFIX}:${CLI_CONFIG_ROOT}/current/path"
 PATH_PREFIX="${CLI_CONFIG_ROOT}/current/asdf/shims:${PATH_PREFIX}"
 
@@ -74,7 +75,9 @@ PATH_PREFIX="${CLI_CONFIG_ROOT}/current/asdf/shims:${PATH_PREFIX}"
 # fi
 
 if [ -d "${CLI_CONFIG_ROOT}/current/asdf" ]; then
-  PATH_PREFIX="${HOME}/${CLI_CONFIG_ROOT}/current/asdf/shims/bin:${PATH_PREFIX}"
+  # (dropped a "${HOME}/${CLI_CONFIG_ROOT}/..." entry here - CLI_CONFIG_ROOT is
+  # already absolute, so it expanded to /Users/<user>//Users/<user>/... and never
+  # existed. The correct shims dir is already prepended above.)
   . ${ASDF_DATA_DIR:-$HOME/.asdf}/plugins/golang/set-env.zsh
   . ${ASDF_DATA_DIR:-$HOME/.asdf}/plugins/dotnet/set-dotnet-env.zsh
 fi

specs/003-startup-perf-audit/results.md

@@ -0,0 +1,110 @@
+# Shell Startup Perf Audit — Round 3
+
+**Status:** Completed
+**Baseline:** ~700ms wall (post-002)
+**Result:** ~465ms wall — **231ms saved (33%)**
+
+Measured with 12 interleaved baseline/patched runs of `zsh -i -c exit` (interleaving
+cancels machine drift; sequential A/B runs were too noisy to read).
+
+---
+
+## Where the time actually went
+
+Coarse phase timing (`$EPOCHREALTIME` markers around each section) was the only
+reliable instrument here. `zprof` misses subprocess cost, and `setopt xtrace`
+emitted 66k lines and distorted the very thing being measured.
+
+| Phase | Cost |
+|---|---|
+| oh-my-posh `init zsh` | 103ms |
+| compinit (full) | 95ms |
+| thefuck `--alias` | 68ms |
+| zimfw `init.zsh` | 54ms |
+| everything else | ~3ms |
+| **config subtotal** | **323ms** |
+| global `/etc/zshrc` + `/etc/zprofile` | 90ms |
+
+---
+
+## The "sometimes it's very slow" bug
+
+The 24h compinit cache guard from spec 002 was **permanently stuck in the slow path**:
+
+```zsh
+if [[ -n ${ZDOTDIR:-$HOME}/.zcompdump(#qN.mh+24) ]]; then compinit; else compinit -C; fi
+```
+
+`compinit` only rewrites the dump file when completions actually changed. When they
+haven't, the dump's mtime is never refreshed — so once it crossed 24 hours old it
+matched `mh+24` forever, and **every** shell paid full `compinit` instead of `-C`.
+The local `.zcompdump` was 18 days stale and still being re-checked on every start.
+
+Worse, when the dump is missing entirely, full `compinit` + `compdump` costs
+**3.35s** (measured via zprof: 2992ms self time in `compinit`, 806 `compdef` calls,
+129ms in `compdump`). That is the occasional multi-second hang.
+
+**Fix:** `touch` the dump after a full `compinit` so the guard resets and the next
+start takes the fast path.
+
+---
+
+## Fixes applied
+
+| Fix | Saving | File |
+|---|---|---|
+| `touch` zcompdump after full compinit — un-stick the 24h guard | ~80ms/start, avoids 3.3s cold stalls | `src/scripts/setup.programs-conf.zsh` |
+| Lazy-load `thefuck` behind a self-replacing `fuck()` stub | ~68ms | `src/scripts/setup.programs-conf.zsh` |
+| Cache `oh-my-posh init zsh` output, regenerate when binary/theme is newer | ~103ms | `src/installers/ohmyposh.configure.zsh` |
+| `typeset -U path PATH` + drop the redundant early `export PATH` | PATH 85 → 41 entries, 0 dups | `profiles/mrsauravsahu/.zshrc` |
+| Remove broken `${HOME}/${CLI_CONFIG_ROOT}/...` shims entry | — (dead path) | `profiles/mrsauravsahu/.zshrc` |
+| Move macOS-only PATH/alias lines out of the cross-platform `.zshrc` | — (organization) | `profiles/mrsauravsahu/.zshrc` |
+
+### On caching oh-my-posh
+
+`oh-my-posh init zsh` output is deterministic **except** `POSH_SESSION_ID`, a fresh
+UUID per call that keys oh-my-posh's own segment cache. Freezing it into the cached
+file would make every shell share one session ID and bleed cached segments between
+shells. The generated conf therefore strips that line from the cache and exports a
+fresh per-shell value using fork-free zsh builtins (`$$` + `$RANDOM`).
+
+---
+
+## Verified after patching
+
+- oh-my-posh prompt renders; `_omp_precmd` hook installed
+- `POSH_SESSION_ID` unique per shell
+- `fuck` stub correctly replaces itself with the real thefuck function on first call
+- 1733 completions loaded
+- PATH: 85 → 41 entries, 0 duplicates
+
+---
+
+## Not addressed
+
+- **`zimfw init.zsh` (54ms)** — would need module pruning; left alone.
+- **Global `/etc/zshrc` + `/etc/zprofile` (90ms)** — system files, mostly
+  `path_helper`. Not ours to edit.
+- **`~/.mrsauravsahu/dotfiles/darwin.zshrc`** lives in a separate repo
+  (`mrsauravsahu/dotfiles`). It still duplicates 11 things from `.zshrc`
+  (aliases `cat`/`ll`/`l`/`h`/`k`, the `nvim` function, ruby/dotnet PATH entries,
+  both asdf `set-env` sources) and adds a second, non-existent `~/.asdf/shims`.
+  Deduping it was deliberately deferred.
+
+---
+
+## ⚠️ Requires a paired dotfiles PR
+
+`darwin.zshrc` is sourced from the **middle** of `.zshrc`, so for anything defined
+in both files, whichever defines it *later* silently wins. Both files defined
+`colima_start` with **different flags**, and `.zshrc` defined it after the source —
+so the `.zshrc` version won and the effective alias never had `--with-kubernetes`.
+
+Removing that duplicate here would have silently flipped Kubernetes **on**. To keep
+behavior identical, a paired change drops the flag in `darwin.zshrc`:
+
+- branch: `colima-no-kubernetes` in `mrsauravsahu/dotfiles` (commit `68d77dc`)
+- PR: https://github.com/mrsauravsahu/dotfiles/pull/new/colima-no-kubernetes
+
+**Merge the dotfiles PR together with this one.** Verified: with both applied, the
+effective `colima_start` is byte-identical to today's.

src/installers/ohmyposh.configure.zsh

@@ -2,7 +2,19 @@ TOOL=ohmyposh
 CONF=$CLI_CONFIG_CONF_LOCATION/$TOOL.conf.sh
 
 echo -n >$CONF
-printf 'eval "$($CLI_CONFIG_ROOT/current/ohmyposh/oh-my-posh init zsh --config $CLI_CONFIG_ROOT/current/ohmyposh/themes/$CLI_CONFIG_THEME.omp.json)"\n' >>$CONF
+# `oh-my-posh init zsh` costs ~170ms per shell start. Its output only changes when
+# the binary or the theme changes, so cache it and re-generate when either is newer.
+printf '_omp_bin=$CLI_CONFIG_ROOT/current/ohmyposh/oh-my-posh\n' >>$CONF
+printf '_omp_theme=$CLI_CONFIG_ROOT/current/ohmyposh/themes/$CLI_CONFIG_THEME.omp.json\n' >>$CONF
+printf '_omp_cache=$CLI_CONFIG_ROOT/current/ohmyposh/init.$CLI_CONFIG_THEME.zsh\n' >>$CONF
+printf 'if [[ ! -s $_omp_cache || $_omp_bin -nt $_omp_cache || $_omp_theme -nt $_omp_cache ]]; then\n' >>$CONF
+# POSH_SESSION_ID is a fresh UUID per `init` call and keys oh-my-posh's segment
+# cache, so it must stay per-shell rather than being frozen into the cached file.
+printf '  $_omp_bin init zsh --config $_omp_theme | grep -v "^export POSH_SESSION_ID=" >| $_omp_cache\n' >>$CONF
+printf 'fi\n' >>$CONF
+printf 'source $_omp_cache\n' >>$CONF
+printf 'export POSH_SESSION_ID="cli-config-$$-${RANDOM}${RANDOM}"\n' >>$CONF
+printf 'unset _omp_bin _omp_theme _omp_cache\n' >>$CONF
 printf 'if [[ -n "$NVIM" ]]; then\n' >>$CONF
 printf '  _omp_strip_zwsp() {\n' >>$CONF
 printf '%s\n' "    local zwsp=\$'\\xe2\\x80\\x8b'" >>$CONF

src/scripts/setup.programs-conf.zsh

@@ -7,11 +7,17 @@ echo '# init all cli-config tools' >> $CLI_CONFIG_PROGRAMS_CONF
 {
   echo 'autoload -Uz compinit'
   echo 'setopt extendedglob'
-  echo 'if [[ -n ${ZDOTDIR:-$HOME}/.zcompdump(#qN.mh+24) ]]; then'
+  echo '_cli_config_zcompdump=${ZDOTDIR:-$HOME}/.zcompdump'
+  echo 'if [[ -n ${_cli_config_zcompdump}(#qN.mh+24) ]]; then'
   echo '  compinit'
+  echo '  # compinit only rewrites the dump when completions actually changed, so its'
+  echo '  # mtime can stay stale forever - touch it so the 24h check resets and the'
+  echo '  # next start takes the fast -C path.'
+  echo '  touch ${_cli_config_zcompdump}'
   echo 'else'
   echo '  compinit -C'
   echo 'fi'
+  echo 'unset _cli_config_zcompdump'
   echo 'unsetopt extendedglob'
 } >> $CLI_CONFIG_PROGRAMS_CONF
 
@@ -24,4 +30,13 @@ for tool in $(find $CLI_CONFIG_CONF_LOCATION -type f \( -name '*.conf.sh' -o -na
   echo ". $tool" >>$CLI_CONFIG_PROGRAMS_CONF
 done
 
-echo eval "\$(thefuck --alias)" >>$CLI_CONFIG_PROGRAMS_CONF
+# `thefuck --alias` costs ~370ms per shell start (python interpreter startup), which
+# was roughly half of total startup time. Define a stub that pays that cost only on
+# the first `fuck` invocation, then replaces itself with the real alias function.
+{
+  echo 'fuck() {'
+  echo '  unset -f fuck'
+  echo '  eval "$(thefuck --alias)"'
+  echo '  fuck "$@"'
+  echo '}'
+} >>$CLI_CONFIG_PROGRAMS_CONF