brew/Library/Homebrew/python_helper.rb
Samuel John ed461359a7 PythonInstalled: set PYTHONPATH, not prepend
An issue could arise when brewing a formula that
has Python 2.x and 3.x support and 2.x is the system Python
but 3.x is a brewed one. The idea about prepending was that
user configured PYTHONPATH could be used in formulae.
Now, instead and if needed, inside the `python do` block
one can still append to PYTHONPATH.
2013-08-27 16:34:31 +02:00

85 lines
3.9 KiB
Ruby

# This helper method is used in the Formula class when the user calls
# `python`, `python2` or `python3`.
# This method has a dual nature. For one, it takes a &block and sets up
# the ENV such that a Python, as defined in the requirements, is the default.
# If there are multiple `PythonInstalled` requirements, the block is evaluated
# once for each Python. This makes it possible to easily support 2.x and
# 3.x Python bindings without code duplication in formulae.
# If you need to special case stuff, set :allowed_major_versions.
# Second, inside the block, a formula author may call this method to access
# certain convienience methods for the currently selected Python, e.g.
# `python.site_packages`.
# This method should be executed in the context of the formula, so that
# prefix is defined. Note, that this method will set @current_python to be
# able to refer to the current python if a block is executed for 2.x and 3.x.
def python_helper(options={:allowed_major_versions => [2, 3]}, &block)
if !block_given? and !@current_python.nil?
# We are already inside of a `python do ... end` block, so just return
# the current_python or false if the version.major is not allowed.
if options[:allowed_major_versions].include?(@current_python.version.major)
return @current_python
else
return false
end
end
# Look for PythonInstalled requirements for this formula
python_reqs = requirements.select{ |r| r.kind_of?(PythonInstalled) }
if python_reqs.empty?
raise "If you use python in the formula, you have to add `depends_on :python` (or :python3)!"
end
# Now select those that are satisfied and matching the version.major and
# check that no two python binaries are the same (which could be the case
# because more than one `depends_on :python => 'module_name' may be present).
filtered_python_reqs = []
python_reqs.each do |py|
next if filtered_python_reqs.any? { |req| req.binary == py.binary }
next unless py.satisfied?
next unless options[:allowed_major_versions].include?(py.version.major)
next if (py.optional? || py.recommended?) && build.without?(py.name)
filtered_python_reqs << py
end
# Allow to use an else-branch like so: `if python do ... end; else ... end`
return false if filtered_python_reqs.empty?
# Sort by version, so the older 2.x will be used first and if no
# block_given? then 2.x is preferred because it is returned.
# Further note, having 3.x last allows us to run `2to3 --write .`
# which modifies the sources in-place (for some packages that need this).
filtered_python_reqs.sort_by{ |py| py.version }.map do |py|
# Now is the time to set the site_packages to the correct value
py.site_packages = lib/py.xy/'site-packages'
return py if !block_given?
puts "brew: Python block (#{py.binary})..." if ARGV.verbose? && ARGV.debug?
# Ensure env changes are only temporary
begin
old_env = ENV.to_hash
# In order to install into the Cellar, the dir must exist and be in the
# PYTHONPATH. This will be executed in the context of the formula
# so that lib points to the HOMEBREW_PREFIX/Cellar/<formula>/<version>/lib
puts "brew: setting PYTHONPATH to: #{py.site_packages}" if ARGV.verbose?
mkdir_p py.site_packages
ENV['PYTHONPATH'] = py.site_packages
ENV['PYTHON'] = py.binary
ENV.prepend_path 'CMAKE_INCLUDE_PATH', py.incdir
ENV.prepend_path 'PKG_CONFIG_PATH', py.pkg_config_path if py.pkg_config_path
ENV.prepend_path 'PATH', py.binary.dirname unless py.from_osx?
#Note: Don't set LDFLAGS to point to the Python.framework, because
# it breaks builds (for example scipy.)
# Track the state of the currently selected python for this block,
# so if this python_helper is called again _inside_ the block,
# we can just return the right python
@current_python = py
res = instance_eval(&block)
@current_python = nil
res
ensure
ENV.replace(old_env)
end
end
end