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
61	#### ${BASH_SOURCE} usable as a string (e.g. for virtualenv)
62
63	# https://github.com/pypa/virtualenv/blob/master/virtualenv_embedded/activate.sh
64
65	argv.py "$BASH_SOURCE" # SimpleVarSUb
66	argv.py "${BASH_SOURCE}" # BracedVarSub
67	source spec/testdata/bash-source-string.sh
68
69	## STDOUT:
70	['']
71	['']
72	['spec/testdata/bash-source-string.sh']
73	['spec/testdata/bash-source-string.sh']
74	['spec/testdata/bash-source-string2.sh']
75	['spec/testdata/bash-source-string2.sh']
76	## END
77
78	#### ${BASH_SOURCE[@]} with source and function name
79	argv.py "${BASH_SOURCE[@]}"
80	source spec/testdata/bash-source-simple.sh
81	f
82	## STDOUT:
83	[]
84	['spec/testdata/bash-source-simple.sh']
85	['spec/testdata/bash-source-simple.sh']
86	## END
87
88	#### ${BASH_SOURCE[@]} with line numbers
89	$SH spec/testdata/bash-source.sh
90	## STDOUT:
91	['begin F funcs', 'f', 'main']
92	['begin F files', 'spec/testdata/bash-source.sh', 'spec/testdata/bash-source.sh']
93	['begin F lines', '21', '0']
94	['G funcs', 'g', 'f', 'main']
95	['G files', 'spec/testdata/bash-source-2.sh', 'spec/testdata/bash-source.sh', 'spec/testdata/bash-source.sh']
96	['G lines', '15', '21', '0']
97	['end F funcs', 'f', 'main']
98	['end F', 'spec/testdata/bash-source.sh', 'spec/testdata/bash-source.sh']
99	['end F lines', '21', '0']
100	## END
101
102	#### ${BASH_LINENO[@]} is a stack of line numbers for function calls
103	# note: it's CALLS, not DEFINITIONS.
104	g() {
105	argv.py G "${BASH_LINENO[@]}"
106	}
107	f() {
108	argv.py 'begin F' "${BASH_LINENO[@]}"
109	g # line 6
110	argv.py 'end F' "${BASH_LINENO[@]}"
111	}
112	argv.py ${BASH_LINENO[@]}
113	f # line 9
114	## STDOUT:
115	[]
116	['begin F', '10']
117	['G', '6', '10']
118	['end F', '10']
119	## END