Now that chainlint.pl is functional, take advantage of the existing
chainlint self-tests to validate its operation. (While at it, stop
validating chainlint.sed against the self-tests since it will soon be
retired.)
Due to chainlint.sed implementation limitations leaking into the
self-test "expect" files, a few of them require minor adjustment to make
them compatible with chainlint.pl which does not share those
limitations.
First, because `sed` does not provide any sort of real recursion,
chainlint.sed only emulates recursion into subshells, and each level of
recursion leads to a multiplicative increase in complexity of the `sed`
rules. To avoid substantial complexity, chainlint.sed, therefore, only
emulates subshell recursion one level deep. Any subshell deeper than
that is passed through as-is, which means that &&-chains are not checked
in deeper subshells. chainlint.pl, on the other hand, employs a proper
recursive descent parser, thus checks subshells to any depth and
correctly flags broken &&-chains in deep subshells.
Second, due to sed's line-oriented nature, chainlint.sed, by necessity,
folds multi-line quoted strings into a single line. chainlint.pl, on the
other hand, employs a proper lexical analyzer which preserves quoted
strings as-is, including embedded newlines.
Furthermore, the output of chainlint.sed and chainlint.pl do not match
precisely in terms of whitespace. However, since the purpose of the
self-checks is to verify that the ?!AMP?! annotations are being
correctly added, minor whitespace differences are immaterial. For this
reason, rather than adjusting whitespace in all existing self-test
"expect" files to match the new linter's output, the `check-chainlint`
target ignores whitespace differences. Since `diff -w` is not POSIX,
`check-chainlint` attempts to employ `git diff -w`, and only falls back
to non-POSIX `diff -w` (and `-u`) if `git diff` is not available.
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
chainlint.sed inserts a ">" annotation at the beginning of a line to
signal that its heuristics have identified an end-of-subshell. This was
useful as a debugging aid during development of the script, but it has
no value to test writers and might even confuse them into thinking that
the linter is misbehaving by inserting line-noise into the shell code it
is validating. Moreover, its presence also potentially makes it
difficult to reuse the chainlint self-test "expect" output should a more
capable linter ever be developed. Therefore, drop the ">" annotation.
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When chainlint.sed detects a broken &&-chain, it places an ?!AMP?!
annotation at the beginning of the line. However, this is an unusual
location for programmers accustomed to error messages (from compilers,
for instance) indicating the exact point of the problem. Therefore,
relocate the ?!AMP?! annotation to the end of the line in order to
better direct the programmer's attention to the source of the problem.
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The chainlint self-test code snippets are supposed to represent the body
of a test_expect_success() or test_expect_failure(), yet the contents of
a few tests would have caused the shell to report syntax errors had they
been real test bodies due to the mix of single- and double-quotes.
Although chainlint.sed, with its simplistic heuristics, is blind to this
problem, a future more robust chainlint implementation might not have
such a limitation. Therefore, stop mixing quote types haphazardly in
those tests and unify quoting throughout. While at it, drop chunks of
tests which merely repeat what is already tested elsewhere but with
alternative quotes.
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
chainlint.sed recognizes multi-line quoted strings within subshells:
echo "abc
def" >out &&
so it can avoid incorrectly classifying lines internal to the string as
breaking the &&-chain. To identify the first line of a multi-line
string, it checks if the line contains a single quote. However, this is
fragile and can be easily fooled by a line containing multiple strings:
echo "xyz" "abc
def" >out &&
Make detection more robust by checking for an odd number of quotes
rather than only a single one.
(Escaped quotes are not handled, but support may be added later.)
The original multi-line string recognizer rather cavalierly threw away
all but the final quote, whereas the new one is careful to retain all
quotes, so the "expected" output of a couple existing chainlint tests is
updated to account for this new behavior.
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The --chain-lint option uses heuristics and knowledge of shell syntax to
detect broken &&-chains in subshells by pure textual inspection. The
heuristics handle a range of stylistic variations in existing tests
(evolved over the years), however, they are still best-guesses. As such,
it is possible for future changes to accidentally break assumptions upon
which the heuristics are based. Protect against this possibility by
adding tests which check the linter itself for correctness.
In addition to protecting against regressions, these tests help document
(for humans) expected behavior, which is important since the linter's
implementation language ('sed') does not necessarily lend itself to easy
comprehension.
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
