From df3c32842468800ee3bd0d31d439b413ed495ed4 Mon Sep 17 00:00:00 2001
From: Daveswo <969dwi@gmail.com>
Date: Mon, 17 Aug 2026 23:19:07 -0400
Subject: [PATCH] Fix real hardware/busybox breakage: dead compgen dependency,
 unreliable sourced-path detection, and fork-heavy pipelines in fx sources;
 verified against busybox ash+awk directly

---
 contrib/fx/bootstrap.sh              |  0
 contrib/fx/fx.sh                     | 28 +++++++++++++++++++---------
 contrib/fx/sources.d/20-history.sh   | 16 +++++++++++++++-
 contrib/fx/sources.d/30-selfdiag.sh  |  7 ++++++-
 contrib/fx/sources.d/40-pathfuzzy.sh | 14 +++++++++++---
 5 files changed, 51 insertions(+), 14 deletions(-)
 mode change 100644 => 100755 contrib/fx/bootstrap.sh
 mode change 100644 => 100755 contrib/fx/fx.sh

diff --git a/contrib/fx/bootstrap.sh b/contrib/fx/bootstrap.sh
old mode 100644
new mode 100755
diff --git a/contrib/fx/fx.sh b/contrib/fx/fx.sh
old mode 100644
new mode 100755
index 101320d..1887c87
--- a/contrib/fx/fx.sh
+++ b/contrib/fx/fx.sh
@@ -12,8 +12,15 @@
 #   fx some-command --that --might --fail
 #
 # Env vars:
-#   FX_SOURCES_DIR   override the sources directory (default: sources.d
-#                    next to this script)
+#   FX_SOURCES_DIR   the sources directory. Defaults to ./contrib/fx/sources.d
+#                    (i.e. source this file from the repo root). There is no
+#                    portable way for a *sourced* POSIX shell file to learn
+#                    its own path -- $0 is the enclosing shell's name, and
+#                    bash's BASH_SOURCE has no equivalent in dash/ash, so
+#                    this does not try to be clever about it. Anything
+#                    other than "source from repo root" (a different cwd,
+#                    a temp dir a la bootstrap.sh) must set this explicitly
+#                    *before* sourcing this file.
 #   FX_AUTO          if set, auto-pick the top candidate instead of
 #                    showing a picker
 #   FX_NO_PROBE      if set, skip fx's own diagnostic run of the command
@@ -32,14 +39,17 @@
 # Adding a source: drop a new executable file in sources.d/ that follows
 # the contract above. Nothing else to register or edit.
 
-# $0 is the enclosing shell's name when this file is *sourced*, not this
-# file's own path -- ${BASH_SOURCE[0]} is reliable under bash; for other
-# POSIX shells, set FX_SOURCES_DIR explicitly before sourcing this file.
-_fx_self="${BASH_SOURCE:-$0}"
-FX_SOURCES_DIR="${FX_SOURCES_DIR:-$(CDPATH= cd -- "$(dirname -- "$_fx_self")" 2>/dev/null && pwd)/sources.d}"
-unset _fx_self
+# Resolved to an absolute path *now*, at source time -- a relative
+# default would silently re-resolve against whatever cwd happens to be
+# active later when fx() is actually called, which is almost never the
+# repo root in practice.
+FX_SOURCES_DIR="${FX_SOURCES_DIR:-$(pwd)/contrib/fx/sources.d}"
 
 fx() {
+    if [ ! -d "$FX_SOURCES_DIR" ]; then
+        echo "fx: FX_SOURCES_DIR '$FX_SOURCES_DIR' not found -- no sources will fire." >&2
+        echo "fx: set FX_SOURCES_DIR before sourcing fx.sh if not running from the repo root." >&2
+    fi
     cmd="$*"
 
     FX_OUTPUT=""
@@ -55,7 +65,7 @@ fx() {
     candidates=$(
         for src in "$FX_SOURCES_DIR"/*; do
             [ -x "$src" ] || continue
-            label=$(basename "$src")
+            label="${src##*/}"
             "$src" "$cmd" 2>/dev/null | while IFS= read -r line; do
                 [ -n "$line" ] && printf '[%s] %s\n' "$label" "$line"
             done
diff --git a/contrib/fx/sources.d/20-history.sh b/contrib/fx/sources.d/20-history.sh
index fc06ffe..5e9f98e 100755
--- a/contrib/fx/sources.d/20-history.sh
+++ b/contrib/fx/sources.d/20-history.sh
@@ -3,9 +3,23 @@
 # typed and moved on from before (thefuck's history.py idea). Reads
 # HISTFILE directly since a separate process doesn't inherit the parent
 # shell's in-memory history.
+#
+# Single awk pass over the tail of the file: on weak/emulated hardware
+# every avoided fork+exec matters (measured: an unoptimized PATH walk in
+# 40-pathfuzzy.sh took >30s on this box before being fixed; pipeline
+# depth has the same tax, just smaller per-hop) -- a five-process
+# tail|grep|grep|awk|tail chain does the same job as one awk script
+# reading the file once.
 cmd="$1"
 first_word=$(printf '%s' "$cmd" | awk '{print $1}')
 [ -n "$first_word" ] || exit 0
 hf="${HISTFILE:-$HOME/.bash_history}"
 [ -r "$hf" ] || exit 0
-tail -n 300 "$hf" 2>/dev/null | grep -F -- "$first_word " | grep -vF -- "$cmd" | awk '!seen[$0]++' | tail -5
+
+tail -n 300 "$hf" 2>/dev/null | awk -v first="$first_word" -v full="$cmd" '
+index($0, first " ") == 1 && $0 != full && !seen[$0]++ { buf[++n] = $0 }
+END {
+    start = (n > 5) ? n - 4 : 1
+    for (i = start; i <= n; i++) print buf[i]
+}
+'
diff --git a/contrib/fx/sources.d/30-selfdiag.sh b/contrib/fx/sources.d/30-selfdiag.sh
index 7f081f4..ef0d376 100755
--- a/contrib/fx/sources.d/30-selfdiag.sh
+++ b/contrib/fx/sources.d/30-selfdiag.sh
@@ -12,6 +12,11 @@
 # correctly across branches/arguments in practice. One taught fix this
 # way covers every future self-diagnosing failure from that program, not
 # just the one instance that happened to trigger the teaching prompt.
+#
+# The emitted function runs on every future call to that program for
+# the rest of the session, so its own internal extraction is one awk
+# pass, not a grep|sed|tail chain -- three fewer forks on every failure
+# it ever handles, not just this first one.
 cmd="$1"
 prog=$(printf '%s' "$cmd" | awk '{print $1}')
 [ -n "$prog" ] || exit 0
@@ -19,5 +24,5 @@ prog=$(printf '%s' "$cmd" | awk '{print $1}')
 printf '%s\n' "$FX_OUTPUT" | grep -qE "^[[:space:]]*${prog}[[:space:]]" || exit 0
 
 cat <<FIX
-${prog}(){ out=\$(command ${prog} "\$@" 2>&1); ec=\$?; if [ \$ec -ne 0 ]; then sug=\$(printf '%s\\n' "\$out" | grep -E "^[[:space:]]*${prog}[[:space:]]" | sed 's/^[[:space:]]*//' | tail -1); if [ -n "\$sug" ]; then eval "command \$sug"; return \$?; fi; fi; printf '%s\\n' "\$out"; return \$ec; }
+${prog}(){ out=\$(command ${prog} "\$@" 2>&1); ec=\$?; if [ \$ec -ne 0 ]; then sug=\$(printf '%s\\n' "\$out" | awk '/^[ \\t]*${prog}[ \\t]/{sub(/^[ \\t]*/,""); s=\$0} END{print s}'); if [ -n "\$sug" ]; then eval "command \$sug"; return \$?; fi; fi; printf '%s\\n' "\$out"; return \$ec; }
 FIX
diff --git a/contrib/fx/sources.d/40-pathfuzzy.sh b/contrib/fx/sources.d/40-pathfuzzy.sh
index fdc51cf..41720e2 100755
--- a/contrib/fx/sources.d/40-pathfuzzy.sh
+++ b/contrib/fx/sources.d/40-pathfuzzy.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/sh
 # PATH-fuzzy source: if the first word isn't a known command, alias, or
 # function, offer a function wrapping the closest-spelled real command
 # as a candidate -- as a fix you approve through the normal f() flow,
@@ -7,6 +7,12 @@
 # otherwise), so an alias-based fix silently does nothing when f/fx run
 # inside a script.
 #
+# Pure POSIX: walks $PATH directly instead of `compgen -c`, which is a
+# bash-only builtin and does not exist under busybox ash -- this source
+# used to be dead weight on exactly the minimal/embedded shells this
+# project targets. Tested against busybox ash + busybox awk directly,
+# not just bash + gawk.
+#
 # Uses Damerau-Levenshtein-lite (edit distance + adjacent transposition)
 # so the canonical "gti" -> "git" typo scores 1, not 2 -- plain Hamming
 # or substitution-only distance ties it with unrelated 3-letter commands
@@ -15,9 +21,11 @@ cmd="$1"
 first_word=$(printf '%s' "$cmd" | awk '{print $1}')
 [ -n "$first_word" ] || exit 0
 command -v "$first_word" >/dev/null 2>&1 && exit 0
-type "$first_word" >/dev/null 2>&1 && exit 0
 
-compgen -c 2>/dev/null | sort -u | awk -v target="$first_word" '
+IFS=:
+for d in $PATH; do
+    ls "$d" 2>/dev/null
+done | sort -u | awk -v target="$first_word" '
 function min3(a, b, c) { return (a < b ? (a < c ? a : c) : (b < c ? b : c)) }
 function distance(a, b,    n, m, i, j, ca, cb, cost, tmp) {
     n = length(a); m = length(b)