On 25/01/2020 01:13, Harald van Dijk wrote:
On 24/01/2020 23:48, Martijn Dekker wrote:
There is a regression involving alias expansion, a here-document, and
a command substitution. The following worked fine until dash 0.5.8; it
throws a syntax error as of dash 0.5.9.
alias BEGIN='{' END='}'
BEGIN
cat <<eof
$(echo hi)
eof
END
Nice find.
When the newline after cat <<eof is seen, checkkwd is changed to
indicate that the shell is in a state where aliases can be expanded.
Then, parseheredoc() is called, which in turn calls readtoken1() to
parse the here-document. readtoken() re-sets checkkwd once it is done,
but readtoken1() does not, so normally this preserves the "can expand
aliases" state. However, nested command substitutions do reset checkkwd,
so things break.
Until 0.5.8, parseheredoc() was called first, and only after that did
checkkwd get changed.
Either parseheredoc() needs to save and restore checkkwd, or the code
calling parseheredoc() needs to ensure that it sets checkkwd as
appropriate afterwards.
There is another place that parseheredoc() can be called from where
checkkwd was not being corrected afterwards:
alias BEGIN='{' END='}'
: <<EOF &&
$(echo hi)
EOF
BEGIN
echo ok
END
This has been failing for longer. This prints "Syntax error: "("
unexpected" since at least 0.5.1.
Cheers,
Harald van Dijk
