From fac51df957a26d440284b839ffac69cd258cde7b Mon Sep 17 00:00:00 2001
From: Mike Bland <mbland@acm.org>
Date: Wed, 15 Feb 2017 11:23:28 -0500
Subject: [PATCH] exec-test: Replace `caller` with `FUNCNAME`, etc.

This is part of the effort to improve performance by reducing the number
of command substitutions/subshells spawned by `bats_debug_trap`.

Under Bash 3.2.57(1)-release on a MacBook Pro with a 2.9GHz Intel Core
i5 CPU and 8GB 1867MHz DDR3 RAM, this makes `bin/bats test/` go from the
following for the previous commit:

  44 tests, 0 failures

  real    0m5.293s
  user    0m2.853s
  sys     0m2.087s

to:

  real    0m4.319s
  user    0m2.559s
  sys     0m1.454s
---
 libexec/bats-exec-test | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/libexec/bats-exec-test b/libexec/bats-exec-test
index 1ffc746..b27a941 100755
--- a/libexec/bats-exec-test
+++ b/libexec/bats-exec-test
@@ -101,16 +101,15 @@ bats_capture_stack_trace() {
   local teardown_pattern=" teardown $BATS_TEST_SOURCE"
 
   local frame
-  local index=1
+  local i
 
-  while frame="$(caller "$index")"; do
+  for ((i=2; i != ${#FUNCNAME[@]}; ++i)); do
+    frame="${BASH_LINENO[$((i-1))]} ${FUNCNAME[$i]} ${BASH_SOURCE[$i]}"
     BATS_CURRENT_STACK_TRACE["${#BATS_CURRENT_STACK_TRACE[@]}"]="$frame"
     if [[ "$frame" = *"$test_pattern"     || \
           "$frame" = *"$setup_pattern"    || \
           "$frame" = *"$teardown_pattern" ]]; then
       break
-    else
-      let index+=1
     fi
   done