1	#!/bin/bash
2	#
3	# Cases relevant to shopt -s strict-errexit in OSH.
4	#
5	# Summary:
6	# - errexit is reset to false in ash/bash -- completely ignored!
7	# - local assignment is different than global! The exit code and errexit
8	# behavior are different because the concept of the "last command" is
9	# different.
10	# - ash has copied bash behavior!
11
12	#### command sub: errexit is NOT inherited
13
14	# This is the bash-specific bug here:
15	# https://blogs.janestreet.com/when-bash-scripts-bite/
16	# See inherit_errexit below.
17	#
18	# I remember finding a script that relies on bash's bad behavior, so OSH copies
19	# it. Instead strict-errexit, is recommended.
20
21	set -o errexit
22	echo $(echo one; false; echo two) # bash/ash keep going
23	echo status=$?
24	## STDOUT:
25	one two
26	status=0
27	## END
28	# dash and mksh: inner shell aborts, but outer one keeps going!
29	## OK dash/mksh STDOUT:
30	one
31	status=0
32	## END
33
34	#### command sub: errexit not ignored with strict-errexit
35	set -o errexit
36
37	# bash implements inherit_errexit, but it's not as strict as OSH.
38	shopt -s inherit_errexit || true
39
40	shopt -s strict-errexit || true
41	echo zero
42	echo $(echo one; false; echo two) # bash/ash keep going
43	echo status=$?
44	## STDOUT:
45	zero
46	## END
47	## status: 1
48	## N-I dash/mksh/bash status: 0
49	## N-I dash/mksh/bash STDOUT:
50	zero
51	one
52	status=0
53	## END
54	## N-I ash status: 0
55	## N-I ash STDOUT:
56	zero
57	one two
58	status=0
59	## END
60
61	#### command sub: last command fails but keeps going and exit code is 0
62	set -o errexit
63	echo $(echo one; false) # we lost the exit code
64	echo status=$?
65	## STDOUT:
66	one
67	status=0
68	## END
69
70	#### global assignment with command sub: middle command fails
71	set -o errexit
72	s=$(echo one; false; echo two;)
73	echo "$s"
74	## status: 0
75	## STDOUT:
76	one
77	two
78	## END
79	# dash and mksh: whole thing aborts!
80	## OK dash/mksh stdout-json: ""
81	## OK dash/mksh status: 1
82
83	#### global assignment with command sub: last command fails and it aborts
84	set -o errexit
85	s=$(echo one; false)
86	echo status=$?
87	## stdout-json: ""
88	## status: 1
89
90	#### local: middle command fails and keeps going
91	set -o errexit
92	f() {
93	echo good
94	local x=$(echo one; false; echo two)
95	echo status=$?
96	echo $x
97	}
98	f
99	## STDOUT:
100	good
101	status=0
102	one two
103	## END
104	# for dash and mksh, the INNER shell aborts, but the outer one keeps going!
105	## OK dash/mksh STDOUT:
106	good
107	status=0
108	one
109	## END
110
111	#### local: last command fails and also keeps going
112	set -o errexit
113	f() {
114	echo good
115	local x=$(echo one; false)
116	echo status=$?
117	echo $x
118	}
119	f
120	## STDOUT:
121	good
122	status=0
123	one
124	## END
125
126	#### local and strict-errexit
127	# I've run into this problem a lot.
128	set -o errexit
129	shopt -s strict-errexit || true # ignore error
130	f() {
131	echo good
132	local x=$(echo one; false; echo two)
133	echo status=$?
134	echo $x
135	}
136	f
137	## status: 1
138	## STDOUT:
139	good
140	## END
141	## N-I bash/ash status: 0
142	## N-I bash/ash STDOUT:
143	good
144	status=0
145	one two
146	## END
147	## N-I dash/mksh status: 0
148	## N-I dash/mksh STDOUT:
149	good
150	status=0
151	one
152	## END
153
154	#### global assignment when last status is failure
155	# this is a bug I introduced
156	set -o errexit
157	[ -n "${BUILDDIR+x}" ] && _BUILDDIR=$BUILDDIR
158	BUILDDIR=${_BUILDDIR-$BUILDDIR}
159	echo status=$?
160	## STDOUT:
161	status=0
162	## END
163
164	#### global assignment when last status is failure
165	# this is a bug I introduced
166	set -o errexit
167	x=$(false) || true # from abuild
168	[ -n "$APORTSDIR" ] && true
169	BUILDDIR=${_BUILDDIR-$BUILDDIR}
170	echo status=$?
171	## STDOUT:
172	status=0
173	## END