"source" cmd creates entry in BASH_SOURCE etc. only if within function

[jim . avera]

Configuration Information [Automatically generated, do not change]:
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='x86_64' 
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='x86_64-unknown-linux-gnu' 
-DCONF_VENDOR='unknown' -DLOCALEDIR='/usr/local/share/locale' -DPACKAGE='bash' 
-DSHELL -DHAVE_CONFIG_H   -I.  -I. -I./include -I./lib   -g -O2
uname output: Linux lxjima 3.11.0-26-generic #45-Ubuntu SMP Tue Jul 15 04:02:06 
UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
Machine Type: x86_64-unknown-linux-gnu

Bash Version: 4.3
Patch Level: 0
Release Status: release

Description:

The "source" (or ".") command, if invoked from within a function,
creates a call frame, setting $FUNCNAME[0] to "source" and
$BASH_SOURCE[1] and $BASH_LINENO[1] to the location of the "source"
statement.

However this does not occur if the "source" statement occurs in
mainline code, i.e. outside of any function.

This means that code in "sourced" files can not reliably 
display the location of their call, i.e., the location of
the "source" (or ".") statement which invoked them.

Repeat-By:

cat <<'EOF' >/tmp/sourced
echo "\$@=$@ \$0=$0 #FUNCNAME=${#FUNCNAME[@]}"
for ((i=0 ; i < ${#FUNCNAME[@]}; i=i+1)) ; do
  echo "(i=$i) FUNCNAME ${FUNCNAME[$i]} called from line ${BASH_LINENO[$i]} in 
${BASH_SOURCE[$i+1]}"
done
EOF

cat <<'EOF' >/tmp/test
#!/bin/bash
myfunc() {
  echo "----- Sourcing from inside a function:"
  source /tmp/sourced
}
myfunc
echo "----- Sourcing from mainline code:"
source /tmp/sourced
EOF

bash /tmp/test

Actual Results:

----- Sourcing from inside function:
$@= $0=/tmp/test #FUNCNAME=3
(i=0) FUNCNAME source called from line 4 in /tmp/test
(i=1) FUNCNAME myfunc called from line 6 in /tmp/test
(i=2) FUNCNAME main called from line 0 in 
----- Sourcing directly from mainline code:
$@= $0=/tmp/test #FUNCNAME=0

Expected Results:

----- Sourcing from inside function:
$@= $0=/tmp/test #FUNCNAME=3
(i=0) FUNCNAME source called from line 4 in /tmp/test
(i=1) FUNCNAME myfunc called from line 6 in /tmp/test
(i=2) FUNCNAME main called from line 0 in 
----- Sourcing directly from mainline code:
$@= $0=/tmp/test #FUNCNAME=1
(i=0) FUNCNAME source called from line 8 in /tmp/test
[(i=1) FUNCNAME main called from line 0 in    ]