sip & pyqt: Now use lib/pythonX.Y/site-packages

Benefit: For brewed Python, adding stuff to the PYTHONPATH is no longer needed.
For other Pythons nothing changes but the X.Y part in the path. Oh, and you
only need to edit your PYTHONPATH once.

- Added a method to get the major.minor version number from the current python
- Updated the caveats to reflect the new path

Fixes #8182.
Closes #10051.

Signed-off-by: Charlie Sharpsteen <source@sharpsteen.net>

2 files changed, 17 insertions, 8 deletions

diff --git a/Library/Formula/pyqt.rb b/Library/Formula/pyqt.rb
index 16fab87f1..91f4f0977 100644
--- a/Library/Formula/pyqt.rb
+++ b/Library/Formula/pyqt.rb
@@ -16,16 +16,20 @@ class Pyqt < Formula
 
     system "python", "./configure.py", "--confirm-license",
                                        "--bindir=#{bin}",
-                                       "--destdir=#{lib}/python",
+                                       "--destdir=#{lib}/#{which_python}/site-packages",
                                        "--sipdir=#{share}/sip"
     system "make"
     system "make install"
   end
 
-  def caveats; <<-EOS
-This formula won't function until you amend your PYTHONPATH like so:
-    export PYTHONPATH=#{HOMEBREW_PREFIX}/lib/python:$PYTHONPATH
-EOS
+  def caveats; <<-EOS.undent
+    For non-homebrew Python, you need to amend your PYTHONPATH like so:
+      export PYTHONPATH=#{HOMEBREW_PREFIX}/lib/#{which_python}/site-packages:$PYTHONPATH
+    EOS
+  end
+
+  def which_python
+    "python" + `python -c 'import sys;print(sys.version[:3])'`.strip
   end
 
   def test
diff --git a/Library/Formula/sip.rb b/Library/Formula/sip.rb
index 6347839fd..4139fe2f1 100644
--- a/Library/Formula/sip.rb
+++ b/Library/Formula/sip.rb
@@ -30,18 +30,23 @@ class Sip < Formula
     inreplace 'build.py', /@SIP_VERSION@/, (sip_version.gsub '.', ',')
 
     system "python", "build.py", "prepare"
+    # Set --destdir such that the python modules will be in the HOMEBREWPREFIX/lib/pythonX.Y/site-packages
     system "python", "configure.py",
-                              "--destdir=#{lib}/python",
+                              "--destdir=#{lib}/#{which_python}/site-packages",
                               "--bindir=#{bin}",
                               "--incdir=#{include}"
     system "make install"
   end
 
   def caveats; <<-EOS.undent
-    This formula won't function until you amend your PYTHONPATH like so:
-      export PYTHONPATH=#{HOMEBREW_PREFIX}/lib/python:$PYTHONPATH
+    For non-homebrew Python, you need to amend your PYTHONPATH like so:
+      export PYTHONPATH=#{HOMEBREW_PREFIX}/lib/#{which_python}/site-packages:$PYTHONPATH
     EOS
   end
+
+  def which_python
+    "python" + `python -c 'import sys;print(sys.version[:3])'`.strip
+  end
 end