defect: reinplace dequotes backslashes incompatibly with sed -E

[JamesC1]

In the course of modifying the Portfile for firefox-x11-devel to build firefox 4.0b, I want this reinplace command:

reinplace -E "s:(libgtk-directfb-2.0).so.0:${prefix}/lib/\1.dylib:" ${worksrcpath}/dom/plugins/PluginModuleChild.cpp

The \1 works in sed -E on the command-line, and substitutes back in a copy of the library name.

After port install, the resulting line in the file reads (in vi):

sGtkLib = PR_LoadLibrary("/opt/local/lib/^A.dylib");

I have inserted some debug output into portutil.tcl. This is one of several attempts, so the line numbers will not agree with your copies.

 # reinplace
 # Provides "sed in place" functionality
 proc reinplace {args}  {
 
+    puts "Because I want to know (args): >>$args<<"
+
     set extended 0
     while 1 {
         set arg [lindex $args 0]
@@ -905,6 +932,9 @@
             lappend cmdline $portutil::autoconf::sed_ext_flag
         }
         set cmdline [concat $cmdline [list $pattern < $file >@ $tmpfd]]
+
+        puts "Because I want to know (sed): >>$cmdline<<"
+

The output I get (which I am wrappng for convenience) from this reads:

Because I want to know (args): >>-E 
  s:(libgtk-directfb-2.0).so.0:/opt/local/lib/.dylib: 
  /opt/local/var/macports/build/
  _Users_jamescone_buildTrees_macports_www_firefox-x11-devel/work/
  mozilla-central/dom/plugins/PluginModuleChild.cpp<<

Because I want to know (sed): >>/usr/bin/sed -E 
  s:(libgtk-directfb-2.0).so.0:/opt/local/lib/.dylib: 
  < /opt/local/var/macports/build/
  _Users_jamescone_buildTrees_macports_www_firefox-x11-devel/work/
  mozilla-central/dom/plugins/PluginModuleChild.cpp >@ file11<<

I assume that there is an invisible control-A in these two lines of printout, before the .dylib. In any event, they show that the sed command is already mangled, before reinplace is called.

I have worked out that the portfile is parsed into a set of runtime-created proc's, but I cannot work out enough of the details to localise the fault.

Help, please.

[jmroot (Joshua Root)]

This is just how Tcl's parser works and we can't really do anything about it. Add additional quoting or escaping as needed, which should be one more backslash in this case.

[JamesC1]

Inserting an explanation for the next confused person.

It's at least partly a feature. As JRM says, the portfile is parsed with the ordinary tcl parser, and happens before anything we can see in the callstack.

Tcl recognises two kinds of strings.

"This kind" does both dollar ($) and backslash (\) substitution before anything I can see gets the data.

{This kind} does neither.

I want dollar substitutions, but not backslash substitutions.

I intend to implement a new option in reinplace, to undo the backslash substitutions. When it's working for me I will open a new ticket as an enhancement.

[JamesC1]

The feature request is here: ​https://trac.macports.org/ticket/27310