[meld] vc: Check for installed version control tools before use

[Kai Willadsen <kaiw src gnome org>]

commit c9131582e59ebe33678d379f37de100f9e984487
Author: Peter Tyser <ptyser gmail com>
Date:   Tue Aug 17 23:47:58 2010 -0500

    vc: Check for installed version control tools before use
    
    Previously, meld blindly assumed that the proper version control software
    was always installed.  This causes issues when the proper version control
    software isn't installed.  For example, if 'bzr' is not installed,
    running "meld ./" in a bzr repository would result in an error such as:
    
    ...
      File "/home/ptyser/meld_git/meld/meld/vc/_vc.py", line 194, in popen
        return subprocess.Popen(cmd, cwd=cwd, stdout=subprocess.PIPE).stdout
      File "/usr/lib/python2.5/subprocess.py", line 594, in __init__
        errread, errwrite)
      File "/usr/lib/python2.5/subprocess.py", line 1147, in _execute_child
        raise child_exception
    OSError: [Errno 2] No such file or directory
    
    This patch forces meld to check if the proper version control software is
    installed before running any version control commands.
    
    Signed-off-by: Peter Tyser <ptyser gmail com>

 meld/vcview.py |   19 +++++++++++++++++--
 1 files changed, 17 insertions(+), 2 deletions(-)
---
diff --git a/meld/vcview.py b/meld/vcview.py
index 9f93a91..c8800b5 100644
--- a/meld/vcview.py
+++ b/meld/vcview.py
@@ -203,10 +203,11 @@ class VcView(melddoc.MeldDoc, gnomeglade.Component):
         # VC ComboBox
         self.combobox_vcs = gtk.ComboBox()
         self.combobox_vcs.lock = True
-        self.combobox_vcs.set_model(gtk.ListStore(str, object))
+        self.combobox_vcs.set_model(gtk.ListStore(str, object, bool))
         cell = gtk.CellRendererText()
         self.combobox_vcs.pack_start(cell, False)
         self.combobox_vcs.add_attribute(cell, 'text', 0)
+        self.combobox_vcs.add_attribute(cell, 'sensitive', 2)
         self.combobox_vcs.lock = False
         self.hbox2.pack_end(self.combobox_vcs, expand=False)
         self.combobox_vcs.show()
@@ -235,7 +236,21 @@ class VcView(melddoc.MeldDoc, gnomeglade.Component):
             if (self.vc is not None and
                 self.vc.__class__ == avc.__class__):
                 default_active = idx
-            self.combobox_vcs.get_model().append([avc.NAME, avc])
+
+            # See if the necessary version control command exists.  If not,
+            # make the version control choice non-selectable.
+            err_str = ""
+            if vc._vc.call(["which", avc.CMD]):
+                # TRANSLATORS: this is an error message when a version control
+                # application isn't installed or can't be found
+                err_str = _("%s Not Installed" % avc.CMD)
+
+            if err_str:
+                self.combobox_vcs.get_model().append( \
+                        [_("%s (%s)") % (avc.NAME, err_str), avc, False])
+            else:
+                self.combobox_vcs.get_model().append([avc.NAME, avc, True])
+
         if gtk.pygtk_version >= (2, 12, 0):
             self.combobox_vcs.set_tooltip_text(tooltip_texts[len(vcs) == 1])
         self.combobox_vcs.set_sensitive(len(vcs) > 1)