Flesh out 'depends' command to display dependencies' status, and halt if

all requirements aren't met.  (Also, check planned install location for
the dependencies, as well as checking sys.path.)  Also:

* Allow 'Feature()' objects to include 'Require()' objects, so that
  dependencies can be optional

* 'Require()' objects can set a homepage, whose URL will be displayed by
  the 'depends' command if the dependency needs to be installed.

* Misc. fixes/refactoring of version validation to properly handle
  "unknown" versions, and to decouple version fetching from version
  checking.

* Updated TODO to remove various completed items.

--HG--
branch : setuptools
extra : convert_revision : svn%3A6015fed2-1504-0410-9fe1-9d1591cc4771/sandbox/trunk/setuptools%4040876

1 files changed, 61 insertions, 6 deletions

diff --git a/setuptools/command/depends.py b/setuptools/command/depends.py
index e149faca..8917c83d 100644
--- a/setuptools/command/depends.py
+++ b/setuptools/command/depends.py
@@ -1,7 +1,9 @@
 from distutils.cmd import Command
-import os
+import os, sys
+
 
 class depends(Command):
+
     """Download and install dependencies, if needed"""
 
     description = "download and install dependencies, if needed"
@@ -13,15 +15,68 @@ class depends(Command):
          "ignore options that won't be passed to child setup scripts"),
     ]
 
+    path_attrs = [
+        # Note: these must be in *reverse* order, as they are pushed onto the
+        # *front* of a copy of sys.path.
+        ('install','install_libbase'),      # installation base if extra_path
+        ('install_lib','install_dir'),      # where modules are installed
+    ]
+
+
     def initialize_options(self):
         self.temp = None
-        self.install_purelib = self.install_platlib = None
-        self.install_lib     = self.install_libbase = None
-        self.install_scripts = self.install_data = self.install_headers = None
-        self.compiler = self.debug = self.force = None
 
     def finalize_options(self):
         self.set_undefined_options('build',('build_temp', 'temp'))
+        self.set_search_path()
+
+    def set_search_path(self):
+        """Determine paths to check for installed dependencies"""
+        path = sys.path[:]  # copy sys path
+        for cmd,attr in self.path_attrs:
+            dir = getattr(self.get_finalized_command(cmd),attr,None)
+            if dir and dir not in path:
+                path.insert(0,dir)  # prepend
+        self.search_path = path
 
     def run(self):
-        self.announce("downloading and building here")
+        self.announce("checking for installed dependencies")
+        needed = [
+            dep for dep in self.distribution.requires if self.is_needed(dep)
+        ]
+        if not needed:
+            self.announce("all dependencies are present and up-to-date")
+            return
+
+        # Alert the user to missing items
+        fmt = "\t%s\t%s\n"
+        items = [fmt % (dep.full_name(),dep.homepage) for dep in needed]
+        items.insert(0,"Please install the following packages first:\n")
+        items.append('')
+        raise SystemExit('\n'.join(items))  # dump msg to stderr and exit
+
+
+    def is_needed(self,dep):
+        """Does the specified dependency need to be installed/updated?"""
+
+        self.announce("searching for "+dep.full_name())
+        version = dep.get_version(self.search_path)
+
+        if version is None:
+            self.announce(name+" not found!")
+            return True
+
+        if str(version)=="unknown":
+            status = dep.name+" is installed"
+        else:
+            status = dep.name+" version "+str(version)+" found"
+
+        if dep.version_ok(version):
+            self.announce(status+" (OK)")
+            return False
+        else:
+            self.announce(status+" (update needed)")
+            return True
+
+
+