update-cargo-metadata: New maintenance script

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/update-cargo-metadata b/update-cargo-metadata
new file mode 100755 (executable)
index 0000000..f86ce6b
--- /dev/null
+++ b/update-cargo-metadata
@@ -0,0 +1,42 @@
+#!/bin/bash
+# usage:
+#    ./update-cargo-metadata
+# copies from toplevel Cargo.toml to others
+# the part copied is the paragraph which starts with version=
+
+set -e
+
+fail () { echo >&2 "${0##*/}: error: $*"; exit 12; }
+
+[ $# = 0 ] || fail "bad usage"
+
+files=$(git ls-files :\*/Cargo.toml :Cargo.toml)
+
+for f in $files; do
+    perl -i~ -pe '
+       BEGIN {
+            $/ = "\n\n";
+           open I, "Cargo.toml" or die $!;
+           our $re = qr{^version\s*\=};
+            our $std;
+           while (<I>) {
+               next unless m{$re};
+               $std = $_;
+               last;
+           }
+           die "not found in ./Cargo.toml" unless defined $std;
+#          $std =~ s{\s*$}{};
+       }
+
+       next unless m{$re};
+       next if $y++;
+#      s{\s*$}{};;
+#      $_ = $std.$&;
+       $_ = $std;
+       END {
+           $y or die "not found in '$f'";
+       }
+    ' $f
+done
+
+echo "working tree file(s) maybe updated, check with git."