1	#!/usr/bin/env bash
2	#
3	# Test call stack introspection. There are a bunch of special variables
4	# defined here:
5	#
6	# https://www.gnu.org/software/bash/manual/html_node/Bash-Variables.html
7	#
8	# - The shell function ${FUNCNAME[$i]} is defined in the file
9	# ${BASH_SOURCE[$i]} and called from ${BASH_SOURCE[$i+1]}
10	#
11	# - ${BASH_LINENO[$i]} is the line number in the source file
12	# (${BASH_SOURCE[$i+1]}) where ${FUNCNAME[$i]} was called (or
13	# ${BASH_LINENO[$i-1]} if referenced within another shell function).
14	#
15	# - For instance, ${FUNCNAME[$i]} was called from the file
16	# ${BASH_SOURCE[$i+1]} at line number ${BASH_LINENO[$i]}. The caller builtin
17	# displays the current call stack using this information.
18	#
19	# So ${BASH_SOURCE[@]} doesn't line up with ${BASH_LINENO}. But
20	# ${BASH_SOURCE[0]} does line up with $LINENO!
21	#
22	# Geez.
23	#
24	# In other words, BASH_SOURCE is about the DEFINITION. While FUNCNAME and
25	# BASH_LINENO are about the CALL.
26
27
28	#### ${FUNCNAME[@]} array
29	g() {
30	argv.py "${FUNCNAME[@]}"
31	}
32	f() {
33	argv.py "${FUNCNAME[@]}"
34	g
35	argv.py "${FUNCNAME[@]}"
36	}
37	f
38	## STDOUT:
39	['f']
40	['g', 'f']
41	['f']
42	## END
43
44	#### FUNCNAME with source
45	f() {
46	. spec/testdata/echo-funcname.sh
47	}
48	g() {
49	f
50	}
51	g
52	. spec/testdata/echo-funcname.sh
53	argv.py "${FUNCNAME[@]}"
54	## STDOUT:
55	['source', 'f', 'g']
56	['source']
57	[]
58	## END
59
60	#### ${BASH_SOURCE[@]} with source and function name
61	argv.py "${BASH_SOURCE[@]}"
62	source spec/testdata/bash-source-simple.sh
63	f
64	## STDOUT:
65	[]
66	['spec/testdata/bash-source-simple.sh']
67	['spec/testdata/bash-source-simple.sh']
68	## END
69
70	#### ${BASH_SOURCE[@]} with line numbers
71	$SH spec/testdata/bash-source.sh
72	## STDOUT:
73	['begin F funcs', 'f', 'main']
74	['begin F files', 'spec/testdata/bash-source.sh', 'spec/testdata/bash-source.sh']
75	['begin F lines', '21', '0']
76	['G funcs', 'g', 'f', 'main']
77	['G files', 'spec/testdata/bash-source-2.sh', 'spec/testdata/bash-source.sh', 'spec/testdata/bash-source.sh']
78	['G lines', '15', '21', '0']
79	['end F funcs', 'f', 'main']
80	['end F', 'spec/testdata/bash-source.sh', 'spec/testdata/bash-source.sh']
81	['end F lines', '21', '0']
82	## END
83
84	#### ${BASH_LINENO[@]} is a stack of line numbers for function calls
85	# note: it's CALLS, not DEFINITIONS.
86	g() {
87	argv.py G "${BASH_LINENO[@]}"
88	}
89	f() {
90	argv.py 'begin F' "${BASH_LINENO[@]}"
91	g # line 6
92	argv.py 'end F' "${BASH_LINENO[@]}"
93	}
94	argv.py ${BASH_LINENO[@]}
95	f # line 9
96	## STDOUT:
97	[]
98	['begin F', '10']
99	['G', '6', '10']
100	['end F', '10']
101	## END