1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
|
#------------------------------------------------------------------------------
# Detect broken &&-chains in tests.
#
# At present, only &&-chains in subshells are examined by this linter;
# top-level &&-chains are instead checked directly by the test framework. Like
# the top-level &&-chain linter, the subshell linter (intentionally) does not
# check &&-chains within {...} blocks.
#
# Checking for &&-chain breakage is done line-by-line by pure textual
# inspection.
#
# Incomplete lines (those ending with "\") are stitched together with following
# lines to simplify processing, particularly of "one-liner" statements.
# Top-level here-docs are swallowed to avoid false positives within the
# here-doc body, although the statement to which the here-doc is attached is
# retained.
#
# Heuristics are used to detect end-of-subshell when the closing ")" is cuddled
# with the final subshell statement on the same line:
#
# (cd foo &&
# bar)
#
# in order to avoid misinterpreting the ")" in constructs such as "x=$(...)"
# and "case $x in *)" as ending the subshell.
#
# Lines missing a final "&&" are flagged with "?!AMP?!", as are lines which
# chain commands with ";" internally rather than "&&". A line may be flagged
# for both violations.
#
# Detection of a missing &&-link in a multi-line subshell is complicated by the
# fact that the last statement before the closing ")" must not end with "&&".
# Since processing is line-by-line, it is not known whether a missing "&&" is
# legitimate or not until the _next_ line is seen. To accommodate this, within
# multi-line subshells, each line is stored in sed's "hold" area until after
# the next line is seen and processed. If the next line is a stand-alone ")",
# then a missing "&&" on the previous line is legitimate; otherwise a missing
# "&&" is a break in the &&-chain.
#
# (
# cd foo &&
# bar
# )
#
# In practical terms, when "bar" is encountered, it is flagged with "?!AMP?!",
# but when the stand-alone ")" line is seen which closes the subshell, the
# "?!AMP?!" violation is removed from the "bar" line (retrieved from the "hold"
# area) since the final statement of a subshell must not end with "&&". The
# final line of a subshell may still break the &&-chain by using ";" internally
# to chain commands together rather than "&&", but an internal "?!AMP?!" is
# never removed from a line even though a line-ending "?!AMP?!" might be.
#
# Care is taken to recognize the last _statement_ of a multi-line subshell, not
# necessarily the last textual _line_ within the subshell, since &&-chaining
# applies to statements, not to lines. Consequently, blank lines, comment
# lines, and here-docs are swallowed (but not the command to which the here-doc
# is attached), leaving the last statement in the "hold" area, not the last
# line, thus simplifying &&-link checking.
#
# The final statement before "done" in for- and while-loops, and before "elif",
# "else", and "fi" in if-then-else likewise must not end with "&&", thus
# receives similar treatment.
#
# Swallowing here-docs with arbitrary tags requires a bit of finesse. When a
# line such as "cat <<EOF >out" is seen, the here-doc tag is moved to the front
# of the line enclosed in angle brackets as a sentinel, giving "<EOF>cat >out".
# As each subsequent line is read, it is appended to the target line and a
# (whitespace-loose) back-reference match /^<(.*)>\n\1$/ is attempted to see if
# the content inside "<...>" matches the entirety of the newly-read line. For
# instance, if the next line read is "some data", when concatenated with the
# target line, it becomes "<EOF>cat >out\nsome data", and a match is attempted
# to see if "EOF" matches "some data". Since it doesn't, the next line is
# attempted. When a line consisting of only "EOF" (and possible whitespace) is
# encountered, it is appended to the target line giving "<EOF>cat >out\nEOF",
# in which case the "EOF" inside "<...>" does match the text following the
# newline, thus the closing here-doc tag has been found. The closing tag line
# and the "<...>" prefix on the target line are then discarded, leaving just
# the target line "cat >out".
#------------------------------------------------------------------------------
# incomplete line -- slurp up next line
:squash
/\\$/ {
N
s/\\\n//
bsquash
}
# here-doc -- swallow it to avoid false hits within its body (but keep the
# command to which it was attached)
/<<-*[ ]*[\\'"]*[A-Za-z0-9_]/ {
/"[^"]*<<[^"]*"/bnotdoc
s/^\(.*\)<<-*[ ]*[\\'"]*\([A-Za-z0-9_][A-Za-z0-9_]*\)['"]*/<\2>\1<</
s/[ ]*<<//
:hered
N
/^<\([^>]*\)>.*\n[ ]*\1[ ]*$/!{
s/\n.*$//
bhered
}
s/^<[^>]*>//
s/\n.*$//
}
:notdoc
# one-liner "(...) &&"
/^[ ]*!*[ ]*(..*)[ ]*&&[ ]*$/boneline
# same as above but without trailing "&&"
/^[ ]*!*[ ]*(..*)[ ]*$/boneline
# one-liner "(...) >x" (or "2>x" or "<x" or "|x" or "&"
/^[ ]*!*[ ]*(..*)[ ]*[0-9]*[<>|&]/boneline
# multi-line "(...\n...)"
/^[ ]*(/bsubsh
# innocuous line -- print it and advance to next line
b
# found one-liner "(...)" -- mark suspect if it uses ";" internally rather than
# "&&" (but not ";" in a string)
:oneline
/;/{
/"[^"]*;[^"]*"/!s/;/; ?!AMP?!/
}
b
:subsh
# bare "(" line? -- stash for later printing
/^[ ]*([ ]*$/ {
h
bnextln
}
# "(..." line -- split off and stash "(", then process "..." as its own line
x
s/.*/(/
x
s/(//
bslurp
:nextln
N
s/.*\n//
:slurp
# incomplete line "...\"
/\\$/bicmplte
# multi-line quoted string "...\n..."?
/"/bdqstr
# multi-line quoted string '...\n...'? (but not contraction in string "it's")
/'/{
/"[^'"]*'[^'"]*"/!bsqstr
}
:folded
# here-doc -- swallow it (but not "<<" in a string)
/<<-*[ ]*[\\'"]*[A-Za-z0-9_]/{
/"[^"]*<<[^"]*"/!bheredoc
}
# comment or empty line -- discard since final non-comment, non-empty line
# before closing ")", "done", "elsif", "else", or "fi" will need to be
# re-visited to drop "suspect" marking since final line of those constructs
# legitimately lacks "&&", so "suspect" mark must be removed
/^[ ]*#/bnextln
/^[ ]*$/bnextln
# in-line comment -- strip it (but not "#" in a string, Bash ${#...} array
# length, or Perforce "//depot/path#42" revision in filespec)
/[ ]#/{
/"[^"]*#[^"]*"/!s/[ ]#.*$//
}
# one-liner "case ... esac"
/^[ ]*case[ ]*..*esac/bchkchn
# multi-line "case ... esac"
/^[ ]*case[ ]..*[ ]in/bcase
# multi-line "for ... done" or "while ... done"
/^[ ]*for[ ]..*[ ]in/bcont
/^[ ]*while[ ]/bcont
/^[ ]*do[ ]/bcont
/^[ ]*do[ ]*$/bcont
/;[ ]*do/bcont
/^[ ]*done[ ]*&&[ ]*$/bdone
/^[ ]*done[ ]*$/bdone
/^[ ]*done[ ]*[<>|]/bdone
/^[ ]*done[ ]*)/bdone
/||[ ]*exit[ ]/bcont
/||[ ]*exit[ ]*$/bcont
# multi-line "if...elsif...else...fi"
/^[ ]*if[ ]/bcont
/^[ ]*then[ ]/bcont
/^[ ]*then[ ]*$/bcont
/;[ ]*then/bcont
/^[ ]*elif[ ]/belse
/^[ ]*elif[ ]*$/belse
/^[ ]*else[ ]/belse
/^[ ]*else[ ]*$/belse
/^[ ]*fi[ ]*&&[ ]*$/bdone
/^[ ]*fi[ ]*$/bdone
/^[ ]*fi[ ]*[<>|]/bdone
/^[ ]*fi[ ]*)/bdone
# nested one-liner "(...) &&"
/^[ ]*(.*)[ ]*&&[ ]*$/bchkchn
# nested one-liner "(...)"
/^[ ]*(.*)[ ]*$/bchkchn
# nested one-liner "(...) >x" (or "2>x" or "<x" or "|x")
/^[ ]*(.*)[ ]*[0-9]*[<>|]/bchkchn
# nested multi-line "(...\n...)"
/^[ ]*(/bnest
# multi-line "{...\n...}"
/^[ ]*{/bblock
# closing ")" on own line -- exit subshell
/^[ ]*)/bclssolo
# "$((...))" -- arithmetic expansion; not closing ")"
/\$(([^)][^)]*))[^)]*$/bchkchn
# "$(...)" -- command substitution; not closing ")"
/\$([^)][^)]*)[^)]*$/bchkchn
# multi-line "$(...\n...)" -- command substitution; treat as nested subshell
/\$([^)]*$/bnest
# "=(...)" -- Bash array assignment; not closing ")"
/=(/bchkchn
# closing "...) &&"
/)[ ]*&&[ ]*$/bclose
# closing "...)"
/)[ ]*$/bclose
# closing "...) >x" (or "2>x" or "<x" or "|x")
/)[ ]*[<>|]/bclose
:chkchn
# mark suspect if line uses ";" internally rather than "&&" (but not ";" in a
# string and not ";;" in one-liner "case...esac")
/;/{
/;;/!{
/"[^"]*;[^"]*"/!s/;/; ?!AMP?!/
}
}
# line ends with pipe "...|" -- valid; not missing "&&"
/|[ ]*$/bcont
# missing end-of-line "&&" -- mark suspect
/&&[ ]*$/!s/$/ ?!AMP?!/
:cont
# retrieve and print previous line
x
n
bslurp
# found incomplete line "...\" -- slurp up next line
:icmplte
N
s/\\\n//
bslurp
# check for multi-line double-quoted string "...\n..." -- fold to one line
:dqstr
# remove all quote pairs
s/"\([^"]*\)"/@!\1@!/g
# done if no dangling quote
/"/!bdqdone
# otherwise, slurp next line and try again
N
s/\n//
bdqstr
:dqdone
s/@!/"/g
bfolded
# check for multi-line single-quoted string '...\n...' -- fold to one line
:sqstr
# remove all quote pairs
s/'\([^']*\)'/@!\1@!/g
# done if no dangling quote
/'/!bsqdone
# otherwise, slurp next line and try again
N
s/\n//
bsqstr
:sqdone
s/@!/'/g
bfolded
# found here-doc -- swallow it to avoid false hits within its body (but keep
# the command to which it was attached)
:heredoc
s/^\(.*\)<<-*[ ]*[\\'"]*\([A-Za-z0-9_][A-Za-z0-9_]*\)['"]*/<\2>\1<</
s/[ ]*<<//
:hdocsub
N
/^<\([^>]*\)>.*\n[ ]*\1[ ]*$/!{
s/\n.*$//
bhdocsub
}
s/^<[^>]*>//
s/\n.*$//
bfolded
# found "case ... in" -- pass through untouched
:case
x
n
/^[ ]*esac/bslurp
bcase
# found "else" or "elif" -- drop "suspect" from final line before "else" since
# that line legitimately lacks "&&"
:else
x
s/\( ?!AMP?!\)* ?!AMP?!$//
x
bcont
# found "done" closing for-loop or while-loop, or "fi" closing if-then -- drop
# "suspect" from final contained line since that line legitimately lacks "&&"
:done
x
s/\( ?!AMP?!\)* ?!AMP?!$//
x
# is 'done' or 'fi' cuddled with ")" to close subshell?
/done.*)/bclose
/fi.*)/bclose
bchkchn
# found nested multi-line "(...\n...)" -- pass through untouched
:nest
x
:nstslrp
n
# closing ")" on own line -- stop nested slurp
/^[ ]*)/bnstcl
# comment -- not closing ")" if in comment
/^[ ]*#/bnstcnt
# "$((...))" -- arithmetic expansion; not closing ")"
/\$(([^)][^)]*))[^)]*$/bnstcnt
# "$(...)" -- command substitution; not closing ")"
/\$([^)][^)]*)[^)]*$/bnstcnt
# closing "...)" -- stop nested slurp
/)/bnstcl
:nstcnt
x
bnstslrp
:nstcl
# is it "))" which closes nested and parent subshells?
/)[ ]*)/bslurp
bchkchn
# found multi-line "{...\n...}" block -- pass through untouched
:block
x
n
# closing "}" -- stop block slurp
/}/bchkchn
bblock
# found closing ")" on own line -- drop "suspect" from final line of subshell
# since that line legitimately lacks "&&" and exit subshell loop
:clssolo
x
s/\( ?!AMP?!\)* ?!AMP?!$//
p
x
b
# found closing "...)" -- exit subshell loop
:close
x
p
x
b
|