On Tuesday, February 19, 2019 7:02:08 PM CET Bruno Haible wrote: > Hi Pavel, > > > > [...] > > > This patch fixes both issues, and makes the IFS handling a bit more > > > robust. > > > [...] > > > > > - case $_fpf_arg in > > > + case "$_fpf_arg" in > > > [...] > > > - fpf_dirs=$1 ; shift > > > - fpf_cb=$1 ; shift > > > + fpf_dirs="$1"; shift > > > + fpf_cb="$1"; shift > > > [...] > > > > ... and so on, I don't think it is more robust. At least according to > > Autoconf's Shellology [1] it should be actually better to write it the > > other way around (without additional quotes). > > I do think it is more robust, because > * The number one mistake in shell scripts (measured by frequency of > occurrence) is to reference variables without double quotes when word > splitting is in fact undesired. > * Simple rules are easier to follow by programmers, resulting in fewer bugs. > * The rule > "Always double-quote shell variable references, except if you DO > want word-splitting." > is simpler than > "Always double-quote shell variable references, except if you DO > want word-splitting OR in the right-hand side of assignments OR > as argument of 'case' statements." > > The text that you quote says two different things: > * Backquotes inside double-quotes are hairy. > There is a simple rule to avoid them: When you have a backquote > expression, always first assign its result to a variable. Then use > the variable (with double-quotes, usually). > * Bash 4.1 has a bug when you WANT word splitting. > These two things don't make my style rule > "Always double-quote shell variable references, except if you DO > want word-splitting." > less robust. > > > FTR, Gary Vaughan has wrote a syntax checker rules for protecting us from > > adding such statements into libtool codebase. > > Opinions regarding coding style differ. Gary is entitled to his opinion, as > much as I am entitled to mine.
Is there a gnulib/GNU-preferred way to do this, defined somewhere? I'd like to avoid such mistakes in future so the code I add doesn't need an unnecessary rewrites (such style changes only complicate git-log reading, and hide the real gist of the changes). Pavel > Bruno > > > [1] https://www.gnu.org/software/autoconf/manual/autoconf-2.69/html_node/ > > Shell-Substitutions.html > > >
