From b4d7f86af736f8e417c7a2c16ac0ce6924236641 Mon Sep 17 00:00:00 2001
From: Ian Kelling <iank@fsf.org>
Date: Mon, 27 Jan 2020 18:47:39 -0500
Subject: [PATCH] handle pipestatus, add some todos

---
 README |  3 ++-
 err    | 35 ++++++++++++++++++++++++++---------
 2 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/README b/README
index 23af1dd..e23ff99 100644
--- a/README
+++ b/README
@@ -1 +1,2 @@
-Read the err file next to this one.
+Todo: populate this readme even though
+the full manual is in the err file.
diff --git a/err b/err
index dc1a218..ccdffee 100644
--- a/err
+++ b/err
@@ -6,6 +6,11 @@
 # functions below for for more details and manual error handling. See
 # end of file for credits etc.
 
+# TODO: investigate to see if we can format output betting in case of
+# subshell failure. Right now, we get independent trace from inside and
+# outside of the subshell. Note, errexit + inherit_errexit doesn't have
+# any smarts around this either.
+
 #######################################
 # err-catch: Setup trap on ERR to print stack trace and exit (or return
 # if the shell is interactive). This is the most common use case so we
@@ -39,9 +44,11 @@ err-catch() {
       )
     fi
     declare -i _err_func_last=0
-    shopt -s extdebug
+    if [[ $- != *c* ]]; then
+      shopt -s extdebug
+    fi
     # shellcheck disable=SC2154
-    trap '_err-bash-trace-interactive $? "$BASH_COMMAND" ${BASH_ARGC[0]} "${BASH_ARGV[@]}" || return $?' ERR
+    trap '_err-bash-trace-interactive $? "${PIPESTATUS[*]}" "$BASH_COMMAND" ${BASH_ARGC[0]} "${BASH_ARGV[@]}" || return $?' ERR
   else
     # Man bash on exdebug: "If set at shell invocation, arrange to
     # execute the debugger". We want to avoid that, but I want this file
@@ -86,9 +93,13 @@ err-allow() {
 #
 #######################################
 err-exit() {
-  local err=$?
+  local err=$? pipestatus="${PIPESTATUS[*]}"
+
   # This has to come before most things or vars get changed
   local msg="${BASH_SOURCE[1]}:${BASH_LINENO[0]}: \`$BASH_COMMAND' returned $err"
+  if [[ $pipestatus != "$err" ]]; then
+    msg+=", PIPESTATUS: $pipestatus"
+  fi
   set +x
   if [[ $1 == -* ]]; then
     err=${1#-}
@@ -176,14 +187,20 @@ _err-bash-trace-interactive() {
   # We have these passed to us because they are lost inside the
   # function.
   ret=$1
-  bash_command="$2"
-  argc=$(( $3 - 1 ))
-  shift 3
+  pipestatus="$2"
+  bash_command="$3"
+  argc=$(( $4 - 1 ))
+  shift 4
   argv=("$@")
   # The trap returns a nonzero, then gets called again. This condition
-  # tells us if we are the first.
-  if (( _err_func_last > last  )); then
-    printf "ERR: \`%s\' returned %s\n" "$bash_command" $ret >&2
+  # tells us if is that has happened by checking if we've gone down a
+  # stack level.
+  if (( _err_func_last >= last  )); then
+    printf "ERR: \`%s\' returned %s" "$bash_command" $ret >&2
+    if [[ $pipestatus != "$ret" ]]; then
+      printf ", PIPESTATUS: %s" "$pipestatus" >&2
+    fi
+    echo >&2
   fi
   printf "  from \`%s" "${FUNCNAME[1]}" >&2
   if shopt extdebug >/dev/null; then
-- 
2.25.1