Changes between Version 66 and Version 67 of PortfileRecipes

Timestamp:

Aug 14, 2013, 7:13:56 AM (11 years ago)

Author:

elelay (Eric Le Lay)

Comment:

document the require_active_variants portgroup

PortfileRecipes

@@ -112 +112 @@
 
 Formerly, use of negatively-named variants (like `no_x11`) was preferred to having a default positively-named variant (like `x11`), due to a deficiency in the port registry (ticket #2377). Now that this is fixed, use of negatively-named variants should be avoided.
+
+== require_active_variants == #require_active_variants
+Depending upon a specific port variant is not possible in MacPorts:
+The quartz variant of a graphic library cannot require automatically that the quartz variant
+of gtk is picked. It's up to the user to issue the correct command and to the port maintainer
+to check for the installed variant.
+
+There was a common practice in Portfiles to check for the presence of a file known to be provided by the wanted variant
+and to display a message requesting the user to install the correct variant if it's missing.
+
+example ([source:trunk/dports/devel/gtk-osx-application/Portfile@109119 gtk-osx-application])
+{{{
+   pre-configure {
+        if {![file exists ${prefix}/lib/pkgconfig/gdk-quartz-3.0.pc]} {
+            ui_error "
+
+****
+**** gtk-osx-application is meant to be used only in a GTK3 quartz
+**** development environment but your version of GTK3 does not
+**** support quartz.  Please make sure that port gtk3 and all its
+**** dependencies are built with variants +no_x11 +quartz and try again.
+****
+"
+            error "gtk3 +no_x11 +quartz not installed."
+        }
+    }
+}}}
+
+A PortGroup has been created to simplify this: [source:trunk/dports/_resources/port1.0/group/active_variants-1.1.tcl active_variants].
+
+To use it:
+1. add {{{ PortGroup       active_variants 1.1 }}} to the top of your Portfile
+2. add {{{ require_active_variants $depspec $required $forbidden}}} 
+   where
+  $depspec:: is the name of the port you're trying to check (required), which can be
+    specified as either just the port, or via "(bin:lib:path):FOO:port"
+    as accepted by the dependency parser.
+  $required:: is a list of variants that must be enabled for the test to succeed
+    (required; remember this can also be a space-separated string or just
+    a string for a single value. It's iterpreted as list, though.)
+  $forbidden:: is a list of variants that may not be enabled for the test to succeed
+    (default is empty list, see description of $required for values that can be
+    interpreted as list by Tcl)
+
+Exemple with gtk-osx-application requiring gtk2+quartz or gtk3+quartz:
+
+{{{
+PortSystem 1.0
+PortGroup  active_variants 1.1
+
+(...)
+
+variant gtk3 conflicts python25 description {Use gtk3} {
+    
+    require_active_variants gtk3 quartz
+    
+    (...)
+}
+
+if {![variant_isset gtk3]} {
+
+    require_active_variants gtk2 quartz
+
+    (...)
+}
+}}}
+
+{{{sudo port install gtk-osx-application +gtk3}}} results in 
+{{{
+--->  Configuring gtk-osx-application
+Error: org.macports.configure for port gtk-osx-application returned: gtk3 must be installed with +quartz.
+To report a bug, follow the instructions in the guide:
+    http://guide.macports.org/#project.tickets
+Error: Processing of port gtk-osx-application failed
+}}}
+
+
+Exemple with py-cairo +x11 requiring /cairo +x11 -quartz/ ([source:trunk/dports/python/py-cairo/Portfile@106520 Portfile])
+and selecting a default variant based on the variants of a cairo:
+{{{
+    variant x11 {
+        require_active_variants path:lib/pkgconfig/cairo.pc:cairo x11 quartz
+    }
+
+    if {![catch {set result [active_variants path:lib/pkgconfig/cairo.pc:cairo x11 quartz]}]} {
+        if {$result} {
+            default_variants +x11
+        }
+    } else {
+        default_variants +x11
+    }
+}}}
+
 
 == cvs/svn/git tag for consistency == #checkout_tag