1 #------------------------------------------------------------------------------
2 # Detect broken &&-chains in tests.
4 # At present, only &&-chains in subshells are examined by this linter;
5 # top-level &&-chains are instead checked directly by the test framework. Like
6 # the top-level &&-chain linter, the subshell linter (intentionally) does not
7 # check &&-chains within {...} blocks.
9 # Checking for &&-chain breakage is done line-by-line by pure textual
12 # Incomplete lines (those ending with "\") are stitched together with following
13 # lines to simplify processing, particularly of "one-liner" statements.
14 # Top-level here-docs are swallowed to avoid false positives within the
15 # here-doc body, although the statement to which the here-doc is attached is
18 # Heuristics are used to detect end-of-subshell when the closing ")" is cuddled
19 # with the final subshell statement on the same line:
24 # in order to avoid misinterpreting the ")" in constructs such as "x=$(...)"
25 # and "case $x in *)" as ending the subshell.
27 # Lines missing a final "&&" are flagged with "?!AMP?!", and lines which chain
28 # commands with ";" internally rather than "&&" are flagged "?!SEMI?!". A line
29 # may be flagged for both violations.
31 # Detection of a missing &&-link in a multi-line subshell is complicated by the
32 # fact that the last statement before the closing ")" must not end with "&&".
33 # Since processing is line-by-line, it is not known whether a missing "&&" is
34 # legitimate or not until the _next_ line is seen. To accommodate this, within
35 # multi-line subshells, each line is stored in sed's "hold" area until after
36 # the next line is seen and processed. If the next line is a stand-alone ")",
37 # then a missing "&&" on the previous line is legitimate; otherwise a missing
38 # "&&" is a break in the &&-chain.
45 # In practical terms, when "bar" is encountered, it is flagged with "?!AMP?!",
46 # but when the stand-alone ")" line is seen which closes the subshell, the
47 # "?!AMP?!" violation is removed from the "bar" line (retrieved from the "hold"
48 # area) since the final statement of a subshell must not end with "&&". The
49 # final line of a subshell may still break the &&-chain by using ";" internally
50 # to chain commands together rather than "&&", so "?!SEMI?!" is never removed
51 # from a line (even though "?!AMP?!" might be).
53 # Care is taken to recognize the last _statement_ of a multi-line subshell, not
54 # necessarily the last textual _line_ within the subshell, since &&-chaining
55 # applies to statements, not to lines. Consequently, blank lines, comment
56 # lines, and here-docs are swallowed (but not the command to which the here-doc
57 # is attached), leaving the last statement in the "hold" area, not the last
58 # line, thus simplifying &&-link checking.
60 # The final statement before "done" in for- and while-loops, and before "elif",
61 # "else", and "fi" in if-then-else likewise must not end with "&&", thus
62 # receives similar treatment.
64 # Swallowing here-docs with arbitrary tags requires a bit of finesse. When a
65 # line such as "cat <<EOF >out" is seen, the here-doc tag is moved to the front
66 # of the line enclosed in angle brackets as a sentinel, giving "<EOF>cat >out".
67 # As each subsequent line is read, it is appended to the target line and a
68 # (whitespace-loose) back-reference match /^<(.*)>\n\1$/ is attempted to see if
69 # the content inside "<...>" matches the entirety of the newly-read line. For
70 # instance, if the next line read is "some data", when concatenated with the
71 # target line, it becomes "<EOF>cat >out\nsome data", and a match is attempted
72 # to see if "EOF" matches "some data". Since it doesn't, the next line is
73 # attempted. When a line consisting of only "EOF" (and possible whitespace) is
74 # encountered, it is appended to the target line giving "<EOF>cat >out\nEOF",
75 # in which case the "EOF" inside "<...>" does match the text following the
76 # newline, thus the closing here-doc tag has been found. The closing tag line
77 # and the "<...>" prefix on the target line are then discarded, leaving just
78 # the target line "cat >out".
80 # To facilitate regression testing (and manual debugging), a ">" annotation is
81 # applied to the line containing ")" which closes a subshell, ">>" to a line
82 # closing a nested subshell, and ">>>" to a line closing both at once. This
83 # makes it easy to detect whether the heuristics correctly identify
85 #------------------------------------------------------------------------------
87 # incomplete line -- slurp up next line
95 # here-doc -- swallow it to avoid false hits within its body (but keep the
96 # command to which it was attached)
97 /<<[ ]*[-\\'"]*[A-Za-z0-9_]/ {
98 s/^\(.*\)<<[ ]*[-\\'"]*\([A-Za-z0-9_][A-Za-z0-9_]*\)['"]*/<\2>\1<</
102 /^<\([^>]*\)>.*\n[ ]*\1[ ]*$/!{
110 # one-liner "(...) &&"
111 /^[ ]*!*[ ]*(..*)[ ]*&&[ ]*$/boneline
113 # same as above but without trailing "&&"
114 /^[ ]*!*[ ]*(..*)[ ]*$/boneline
116 # one-liner "(...) >x" (or "2>x" or "<x" or "|x" or "&"
117 /^[ ]*!*[ ]*(..*)[ ]*[0-9]*[<>|&]/boneline
119 # multi-line "(...\n...)"
122 # innocuous line -- print it and advance to next line
125 # found one-liner "(...)" -- mark suspect if it uses ";" internally rather than
126 # "&&" (but not ";" in a string)
129 /"[^"]*;[^"]*"/!s/^/?!SEMI?!/
136 # stash for later printing
140 # "(..." line -- split off and stash "(", then process "..." as its own line
152 # incomplete line "...\"
154 # multi-line quoted string "...\n..."?
156 # multi-line quoted string '...\n...'? (but not contraction in string "it's")
158 /"[^'"]*'[^'"]*"/!bsqstring
161 # here-doc -- swallow it
162 /<<[ ]*[-\\'"]*[A-Za-z0-9_]/bheredoc
163 # comment or empty line -- discard since final non-comment, non-empty line
164 # before closing ")", "done", "elsif", "else", or "fi" will need to be
165 # re-visited to drop "suspect" marking since final line of those constructs
166 # legitimately lacks "&&", so "suspect" mark must be removed
169 # in-line comment -- strip it (but not "#" in a string, Bash ${#...} array
170 # length, or Perforce "//depot/path#42" revision in filespec)
172 /"[^"]*#[^"]*"/!s/[ ]#.*$//
174 # one-liner "case ... esac"
175 /^[ ]*case[ ]*..*esac/bcheckchain
176 # multi-line "case ... esac"
177 /^[ ]*case[ ]..*[ ]in/bcase
178 # multi-line "for ... done" or "while ... done"
179 /^[ ]*for[ ]..*[ ]in/bcontinue
180 /^[ ]*while[ ]/bcontinue
181 /^[ ]*do[ ]/bcontinue
182 /^[ ]*do[ ]*$/bcontinue
184 /^[ ]*done[ ]*&&[ ]*$/bdone
185 /^[ ]*done[ ]*$/bdone
186 /^[ ]*done[ ]*[<>|]/bdone
187 /^[ ]*done[ ]*)/bdone
188 /||[ ]*exit[ ]/bcontinue
189 /||[ ]*exit[ ]*$/bcontinue
190 # multi-line "if...elsif...else...fi"
191 /^[ ]*if[ ]/bcontinue
192 /^[ ]*then[ ]/bcontinue
193 /^[ ]*then[ ]*$/bcontinue
196 /^[ ]*elif[ ]*$/belse
198 /^[ ]*else[ ]*$/belse
199 /^[ ]*fi[ ]*&&[ ]*$/bdone
201 /^[ ]*fi[ ]*[<>|]/bdone
203 # nested one-liner "(...) &&"
204 /^[ ]*(.*)[ ]*&&[ ]*$/bcheckchain
205 # nested one-liner "(...)"
206 /^[ ]*(.*)[ ]*$/bcheckchain
207 # nested one-liner "(...) >x" (or "2>x" or "<x" or "|x")
208 /^[ ]*(.*)[ ]*[0-9]*[<>|]/bcheckchain
209 # nested multi-line "(...\n...)"
211 # multi-line "{...\n...}"
213 # closing ")" on own line -- exit subshell
215 # "$((...))" -- arithmetic expansion; not closing ")"
216 /\$(([^)][^)]*))[^)]*$/bcheckchain
217 # "$(...)" -- command substitution; not closing ")"
218 /\$([^)][^)]*)[^)]*$/bcheckchain
219 # multi-line "$(...\n...)" -- command substitution; treat as nested subshell
221 # "=(...)" -- Bash array assignment; not closing ")"
227 # closing "...) >x" (or "2>x" or "<x" or "|x")
230 # mark suspect if line uses ";" internally rather than "&&" (but not ";" in a
231 # string and not ";;" in one-liner "case...esac")
234 /"[^"]*;[^"]*"/!s/^/?!SEMI?!/
237 # line ends with pipe "...|" -- valid; not missing "&&"
239 # missing end-of-line "&&" -- mark suspect
240 /&&[ ]*$/!s/^/?!AMP?!/
242 # retrieve and print previous line
247 # found incomplete line "...\" -- slurp up next line
253 # check for multi-line double-quoted string "...\n..." -- fold to one line
255 # remove all quote pairs
256 s/"\([^"]*\)"/@!\1@!/g
257 # done if no dangling quote
259 # otherwise, slurp next line and try again
267 # check for multi-line single-quoted string '...\n...' -- fold to one line
269 # remove all quote pairs
270 s/'\([^']*\)'/@!\1@!/g
271 # done if no dangling quote
273 # otherwise, slurp next line and try again
281 # found here-doc -- swallow it to avoid false hits within its body (but keep
282 # the command to which it was attached)
284 s/^\(.*\)<<[ ]*[-\\'"]*\([A-Za-z0-9_][A-Za-z0-9_]*\)['"]*/<\2>\1<</
288 /^<\([^>]*\)>.*\n[ ]*\1[ ]*$/!{
296 # found "case ... in" -- pass through untouched
303 # found "else" or "elif" -- drop "suspect" from final line before "else" since
304 # that line legitimately lacks "&&"
311 # found "done" closing for-loop or while-loop, or "fi" closing if-then -- drop
312 # "suspect" from final contained line since that line legitimately lacks "&&"
317 # is 'done' or 'fi' cuddled with ")" to close subshell?
322 # found nested multi-line "(...\n...)" -- pass through untouched
327 # closing ")" on own line -- stop nested slurp
329 # comment -- not closing ")" if in comment
330 /^[ ]*#/bnestcontinue
331 # "$((...))" -- arithmetic expansion; not closing ")"
332 /\$(([^)][^)]*))[^)]*$/bnestcontinue
333 # "$(...)" -- command substitution; not closing ")"
334 /\$([^)][^)]*)[^)]*$/bnestcontinue
335 # closing "...)" -- stop nested slurp
342 # is it "))" which closes nested and parent subshells?
346 # found multi-line "{...\n...}" block -- pass through untouched
350 # closing "}" -- stop block slurp
354 # found closing ")" on own line -- drop "suspect" from final line of subshell
355 # since that line legitimately lacks "&&" and exit subshell loop
364 # found closing "...)" -- exit subshell loop