Fix LC_ALL being overwritten by goenv, breaking TUI apps and locale-dependent programs (#489)

* Initial plan

* Fix LC_ALL being reset by goenv - preserve user's locale settings

Co-authored-by: ChronosMasterOfAllTime <28963807+ChronosMasterOfAllTime@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: ChronosMasterOfAllTime <28963807+ChronosMasterOfAllTime@users.noreply.github.com>

Author: Copilot

libexec/goenv

@@ -1,7 +1,12 @@
 #!/usr/bin/env bash
 set -e
 export -n CDPATH
-export LC_ALL=C # boost grep performance by disabling unicode
+
+# Save original LC_ALL to restore later
+GOENV_ORIGINAL_LC_ALL="${LC_ALL:-}"
+
+# Temporarily set LC_ALL=C to boost grep performance by disabling unicode
+export LC_ALL=C
 
 if [ "$1" = "--debug" ]; then
   export GOENV_DEBUG=1
@@ -24,6 +29,15 @@ abort() {
   exit 1
 }
 
+# Restore original LC_ALL before executing commands
+restore_lc_all() {
+  if [ -n "$GOENV_ORIGINAL_LC_ALL" ]; then
+    export LC_ALL="$GOENV_ORIGINAL_LC_ALL"
+  else
+    unset LC_ALL
+  fi
+}
+
 if enable -f "${BASH_SOURCE%/*}"/../libexec/goenv-realpath.dylib realpath 2>/dev/null; then
   abs_dirname() {
     local path="$(realpath "$1")"
@@ -121,13 +135,16 @@ case "$command" in
   } | abort
   ;;
 -v | --version)
+  restore_lc_all
   exec goenv---version
   ;;
 -h | --help)
+  restore_lc_all
   exec goenv-help
   ;;
 # NOTE: Provide goenv completions
 --complete)
+  restore_lc_all
   exec goenv-commands
   ;;
 *)
@@ -149,8 +166,10 @@ case "$command" in
   fi
 
   if [ "$1" = --help ]; then
+    restore_lc_all
     exec goenv-help "$command"
   else
+    restore_lc_all
     exec "$command_path" "$@"
   fi
   ;;

test/goenv-exec.bats

@@ -350,3 +350,36 @@ $GOENV_ROOT/versions/1.12.0
 /tmp/goenv/example/1.12.0
 OUT
 }
+
+@test "preserves LC_ALL environment variable when executing commands" {
+  create_version "1.12.0"
+  create_executable "1.12.0" "go-lc" <<SH
+#!$BASH
+echo "LC_ALL=\$LC_ALL"
+SH
+
+  LC_ALL=en_US.UTF-8 GOENV_VERSION=1.12.0 PATH=${GOENV_TEST_DIR}:${PATH} run goenv-exec go-lc
+
+  assert_success_out <<OUT
+LC_ALL=en_US.UTF-8
+OUT
+}
+
+@test "LC_ALL remains unset if it was not set before" {
+  create_version "1.12.0"
+  create_executable "1.12.0" "go-lc" <<SH
+#!$BASH
+if [ -z "\$LC_ALL" ]; then
+  echo "LC_ALL is unset"
+else
+  echo "LC_ALL=\$LC_ALL"
+fi
+SH
+
+  unset LC_ALL
+  GOENV_VERSION=1.12.0 PATH=${GOENV_TEST_DIR}:${PATH} run goenv-exec go-lc
+
+  assert_success_out <<OUT
+LC_ALL is unset
+OUT
+}