Added an api to change the default policy for unzipping zip-safe eggs.

src/zc/buildout/easy_install.py

@@ -125,13 +125,14 @@ class Installer:
     _prefer_final = True
     _use_dependency_links = True
     _allow_picked_versions = True
+    _always_unzip = False
     
     def __init__(self,
                  dest=None,
                  links=(),
                  index=None,
                  executable=sys.executable,
-                 always_unzip=False,
+                 always_unzip=None,
                  path=None,
                  newest=True,
                  versions=None,
@@ -156,6 +157,7 @@ class Installer:
 
         self._index_url = index
         self._executable = executable
+        if always_unzip is not None:
             self._always_unzip = always_unzip
         path = (path and path[:] or []) + buildout_and_setuptools_path
         if dest is not None and dest not in path:
@@ -740,9 +742,15 @@ def allow_picked_versions(setting=None):
         Installer._allow_picked_versions = bool(setting)
     return old
 
+def always_unzip(setting=None):
+    old = Installer._always_unzip
+    if setting is not None:
+        Installer._always_unzip = bool(setting)
+    return old
+
 def install(specs, dest,
             links=(), index=None,
-            executable=sys.executable, always_unzip=False,
+            executable=sys.executable, always_unzip=None,
             path=None, working_set=None, newest=True, versions=None,
             use_dependency_links=None, allow_hosts=('*',)):
     installer = Installer(dest, links, index, executable, always_unzip, path,

src/zc/buildout/easy_install.txt

@@ -220,6 +220,45 @@ can be useful when debugging.
     d  demo-0.3-py2.4.egg
     d  demoneeded-1.1-py2.4.egg
     
+    >>> rmdir(dest)
+    >>> dest = tmpdir('sample-install')
+    >>> ws = zc.buildout.easy_install.install(
+    ...     ['demo'], dest, links=[link_server], index=link_server+'index/',
+    ...     always_unzip=False)
+
+    >>> ls(dest)
+    -  demo-0.3-py2.4.egg
+    -  demoneeded-1.1-py2.4.egg
+
+We can also set a default by calling the always_unzip function:
+
+    >>> zc.buildout.easy_install.always_unzip(True)
+    False
+
+The old default is returned:
+
+    >>> rmdir(dest)
+    >>> dest = tmpdir('sample-install')
+    >>> ws = zc.buildout.easy_install.install(
+    ...     ['demo'], dest, links=[link_server], index=link_server+'index/')
+
+    >>> ls(dest)
+    d  demo-0.3-py2.4.egg
+    d  demoneeded-1.1-py2.4.egg
+
+
+    >>> zc.buildout.easy_install.always_unzip(False)
+    True
+
+    >>> rmdir(dest)
+    >>> dest = tmpdir('sample-install')
+    >>> ws = zc.buildout.easy_install.install(
+    ...     ['demo'], dest, links=[link_server], index=link_server+'index/')
+
+    >>> ls(dest)
+    -  demo-0.3-py2.4.egg
+    -  demoneeded-1.1-py2.4.egg
+
     >>> rmdir(dest)
     >>> dest = tmpdir('sample-install')
     >>> ws = zc.buildout.easy_install.install(