Re: [Patch v2 1/4] nmbug: use dump --format=batch-tag

[Tomi Ollila <tomi.ollila@iki.fi>]

On Thu, Feb 21 2013, david@tethera.net wrote:

> From: David Bremner <bremner@debian.org>
>
> This should make nmbug tolerate tags with whitespace and other special
> characters it.  At the moment this relies on _not_ passing calls to
> notmuch tag through the shell, which is a documented feature of perl's
> system function.

This patch series looks good to me (as far as I can understand, I did
not find the "silly bug" in your previous patch...)

Instead of mentioning that "calls are _not_ passed to shell" here,
that could be briefly mentioned just before system() calls in the
script -- and that definitely should not be 'At the moment' feature.

the system() function in perl(1) never pass execution through the
shell in case the args are list more than one arg:

1 $ perl -e 'system( qw/echo |cat; echo second line ?/ )'
|cat; echo second line ?

2 $ perl -le 'system( qw/echo| cat;/ ); print "system: ",$!'
system: No such file or directory

3 $ perl -le 'system( qw/echo|/ ); print "system: ",$!'
sh: -c: line 1: syntax error: unexpected end of file
system:

execve calls to the above could have been:

1: execve( "/bin/echo" [ "echo" "|cat;" "echo" "second" "line" "?" ] )

2: no execve: perl(1) did not find 'echo|' in the PATH

3: execve( "/bin/sh" [ "sh" "-c" "echo|" ] )

Tomi

> ---
>  devel/nmbug/nmbug |   27 ++++++++++++++++++++-------
>  1 file changed, 20 insertions(+), 7 deletions(-)
>
> diff --git a/devel/nmbug/nmbug b/devel/nmbug/nmbug
> index fe103b3..befc3d9 100755
> --- a/devel/nmbug/nmbug
> +++ b/devel/nmbug/nmbug
> @@ -39,6 +39,11 @@ my %command = (
>  	     status	=> \&do_status,
>  	     );
>  
> +# Convert prefix into form suitable for literal matching against
> +# notmuch dump --format=batch-tag output.
> +my $ENCPREFIX = encode_for_fs ($TAGPREFIX);
> +$ENCPREFIX =~ s/:/%3a/g;
> +
>  my $subcommand = shift || usage ();
>  
>  if (!exists $command{$subcommand}) {
> @@ -203,9 +208,9 @@ sub index_tags {
>  
>    my $index = $NMBGIT.'/nmbug.index';
>  
> -  my $query = join ' ', map ("tag:$_", get_tags ($TAGPREFIX));
> +  my $query = join ' ', map ("tag:\"$_\"", get_tags ($TAGPREFIX));
>  
> -  my $fh = spawn ('-|', qw/notmuch dump --/, $query)
> +  my $fh = spawn ('-|', qw/notmuch dump --format=batch-tag --/, $query)
>      or die "notmuch dump: $!";
>  
>    git ('read-tree', '--empty');
> @@ -214,22 +219,30 @@ sub index_tags {
>      or die 'git update-index';
>  
>    while (<$fh>) {
> -    m/ ( [^ ]* ) \s+ \( ([^\)]* ) \) /x || die 'syntax error in dump';
> -    my ($id,$rest) = ($1,$2);
>  
> -    #strip prefixes before writing
> -    my @tags = grep { s/^$TAGPREFIX//; } split (' ', $rest);
> +    chomp();
> +    my ($rest,$id) = split(/ -- id:/);
> +
> +    if ($id =~ s/^"(.*)"\s*$/$1/) {
> +      # xapian quoted string, dequote.
> +      $id =~ s/""/"/g;
> +    }
> +
> +    #strip prefixes from tags before writing
> +    my @tags = grep { s/^[+]$ENCPREFIX//; } split (' ', $rest);
>      index_tags_for_msg ($git,$id, 'A', @tags);
>    }
>    unless (close $git) {
>      die "'git update-index --index-info' exited with nonzero value\n";
>    }
>    unless (close $fh) {
> -    die "'notmuch dump -- $query' exited with nonzero value\n";
> +    die "'notmuch dump --format=batch-tag -- $query' exited with nonzero value\n";
>    }
>    return $index;
>  }
>  
> +# update the git index to either create or delete an empty file.
> +# Neither argument should be encoded/escaped.
>  sub index_tags_for_msg {
>    my $fh = shift;
>    my $msgid = shift;
> -- 
> 1.7.10.4
>
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