464 lines
17 KiB
Ruby
464 lines
17 KiB
Ruby
require 'set'
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# This is the latest iteration of the gem dependency resolving algorithm. As of now,
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# it can resolve (as a success or failure) any set of gem dependencies we throw at it
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# in a reasonable amount of time. The most iterations I've seen it take is about 150.
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# The actual implementation of the algorithm is not as good as it could be yet, but that
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# can come later.
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# Extending Gem classes to add necessary tracking information
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module Gem
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class Specification
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def required_by
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@required_by ||= []
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end
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end
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class Dependency
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def required_by
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@required_by ||= []
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end
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end
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end
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module Bundler
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class Resolver
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ALL = Bundler::Dependency::PLATFORM_MAP.values.uniq.freeze
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class SpecGroup < Array
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include GemHelpers
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attr_reader :activated, :required_by
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def initialize(a)
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super
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@required_by = []
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@activated = []
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@dependencies = nil
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@specs = {}
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ALL.each do |p|
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@specs[p] = reverse.find { |s| s.match_platform(p) }
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end
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end
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def initialize_copy(o)
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super
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@required_by = o.required_by.dup
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@activated = o.activated.dup
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end
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def to_specs
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specs = {}
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@activated.each do |p|
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if s = @specs[p]
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platform = generic(Gem::Platform.new(s.platform))
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next if specs[platform]
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lazy_spec = LazySpecification.new(name, version, platform, source)
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lazy_spec.dependencies.replace s.dependencies
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specs[platform] = lazy_spec
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end
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end
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specs.values
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end
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def activate_platform(platform)
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unless @activated.include?(platform)
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@activated << platform
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return __dependencies[platform] || []
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end
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[]
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end
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def name
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@name ||= first.name
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end
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def version
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@version ||= first.version
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end
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def source
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@source ||= first.source
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end
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def for?(platform)
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@specs[platform]
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end
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def to_s
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"#{name} (#{version})"
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end
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private
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def __dependencies
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@dependencies ||= begin
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dependencies = {}
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ALL.each do |p|
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if spec = @specs[p]
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dependencies[p] = []
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spec.dependencies.each do |dep|
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next if dep.type == :development
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dependencies[p] << DepProxy.new(dep, p)
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end
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end
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end
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dependencies
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end
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end
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end
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attr_reader :errors
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# Figures out the best possible configuration of gems that satisfies
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# the list of passed dependencies and any child dependencies without
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# causing any gem activation errors.
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#
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# ==== Parameters
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# *dependencies<Gem::Dependency>:: The list of dependencies to resolve
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#
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# ==== Returns
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# <GemBundle>,nil:: If the list of dependencies can be resolved, a
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# collection of gemspecs is returned. Otherwise, nil is returned.
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def self.resolve(requirements, index, source_requirements = {}, base = [])
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base = SpecSet.new(base) unless base.is_a?(SpecSet)
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resolver = new(index, source_requirements, base)
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result = catch(:success) do
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resolver.start(requirements)
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raise resolver.version_conflict
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nil
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end
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SpecSet.new(result)
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end
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def initialize(index, source_requirements, base)
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@errors = {}
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@stack = []
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@base = base
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@index = index
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@gems_size = {}
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@missing_gems = Hash.new(0)
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@source_requirements = source_requirements
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end
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def debug
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if ENV['DEBUG_RESOLVER']
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debug_info = yield
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debug_info = debug_info.inspect unless debug_info.is_a?(String)
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$stderr.puts debug_info
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end
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end
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def successify(activated)
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activated.values.map { |s| s.to_specs }.flatten.compact
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end
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def start(reqs)
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activated = {}
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resolve(reqs, activated)
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end
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def resolve(reqs, activated)
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# If the requirements are empty, then we are in a success state. Aka, all
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# gem dependencies have been resolved.
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throw :success, successify(activated) if reqs.empty?
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debug { print "\e[2J\e[f" ; "==== Iterating ====\n\n" }
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# Sort dependencies so that the ones that are easiest to resolve are first.
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# Easiest to resolve is defined by:
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# 1) Is this gem already activated?
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# 2) Do the version requirements include prereleased gems?
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# 3) Sort by number of gems available in the source.
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reqs = reqs.sort_by do |a|
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[ activated[a.name] ? 0 : 1,
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a.requirement.prerelease? ? 0 : 1,
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@errors[a.name] ? 0 : 1,
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activated[a.name] ? 0 : gems_size(a) ]
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end
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debug { "Activated:\n" + activated.values.map { |a| " #{a.name} (#{a.version})" }.join("\n") }
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debug { "Requirements:\n" + reqs.map { |r| " #{r.name} (#{r.requirement})"}.join("\n") }
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activated = activated.dup
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# Pull off the first requirement so that we can resolve it
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current = reqs.shift
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debug { "Attempting:\n #{current.name} (#{current.requirement})"}
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# Check if the gem has already been activated, if it has, we will make sure
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# that the currently activated gem satisfies the requirement.
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existing = activated[current.name]
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if existing || current.name == 'bundler'
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# Force the current
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if current.name == 'bundler' && !existing
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existing = search(DepProxy.new(Gem::Dependency.new('bundler', VERSION), Gem::Platform::RUBY)).first
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raise GemNotFound, %Q{Bundler could not find gem "bundler" (#{VERSION})} unless existing
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existing.required_by << existing
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activated['bundler'] = existing
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end
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if current.requirement.satisfied_by?(existing.version)
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debug { " * [SUCCESS] Already activated" }
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@errors.delete(existing.name)
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# Since the current requirement is satisfied, we can continue resolving
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# the remaining requirements.
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# I have no idea if this is the right way to do it, but let's see if it works
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# The current requirement might activate some other platforms, so let's try
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# adding those requirements here.
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reqs.concat existing.activate_platform(current.__platform)
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resolve(reqs, activated)
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else
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debug { " * [FAIL] Already activated" }
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@errors[existing.name] = [existing, current]
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debug { current.required_by.map {|d| " * #{d.name} (#{d.requirement})" }.join("\n") }
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# debug { " * All current conflicts:\n" + @errors.keys.map { |c| " - #{c}" }.join("\n") }
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# Since the current requirement conflicts with an activated gem, we need
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# to backtrack to the current requirement's parent and try another version
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# of it (maybe the current requirement won't be present anymore). If the
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# current requirement is a root level requirement, we need to jump back to
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# where the conflicting gem was activated.
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parent = current.required_by.last
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# `existing` could not respond to required_by if it is part of the base set
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# of specs that was passed to the resolver (aka, instance of LazySpecification)
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parent ||= existing.required_by.last if existing.respond_to?(:required_by)
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# We track the spot where the current gem was activated because we need
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# to keep a list of every spot a failure happened.
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if parent && parent.name != 'bundler'
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debug { " -> Jumping to: #{parent.name}" }
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required_by = existing.respond_to?(:required_by) && existing.required_by.last
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throw parent.name, required_by && required_by.name
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else
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# The original set of dependencies conflict with the base set of specs
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# passed to the resolver. This is by definition an impossible resolve.
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raise version_conflict
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end
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end
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else
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# There are no activated gems for the current requirement, so we are going
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# to find all gems that match the current requirement and try them in decending
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# order. We also need to keep a set of all conflicts that happen while trying
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# this gem. This is so that if no versions work, we can figure out the best
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# place to backtrack to.
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conflicts = Set.new
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# Fetch all gem versions matching the requirement
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#
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# TODO: Warn / error when no matching versions are found.
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matching_versions = search(current)
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if matching_versions.empty?
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if current.required_by.empty?
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if base = @base[current.name] and !base.empty?
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version = base.first.version
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message = "You have requested:\n" \
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" #{current.name} #{current.requirement}\n\n" \
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"The bundle currently has #{current.name} locked at #{version}.\n" \
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"Try running `bundle update #{current.name}`"
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elsif current.source
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name = current.name
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versions = @source_requirements[name][name].map { |s| s.version }
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message = "Could not find gem '#{current}' in #{current.source}.\n"
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if versions.any?
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message << "Source contains '#{name}' at: #{versions.join(', ')}"
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else
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message << "Source does not contain any versions of '#{current}'"
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end
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else
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message = "Could not find gem '#{current}' "
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if @index.sources.include?(Bundler::Source::Rubygems)
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message << "in any of the gem sources listed in your Gemfile."
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else
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message << "in the gems available on this machine."
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end
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end
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raise GemNotFound, message
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else
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@errors[current.name] = [nil, current]
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end
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end
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matching_versions.reverse_each do |spec_group|
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conflict = resolve_requirement(spec_group, current, reqs.dup, activated.dup)
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conflicts << conflict if conflict
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end
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# If the current requirement is a root level gem and we have conflicts, we
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# can figure out the best spot to backtrack to.
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if current.required_by.empty? && !conflicts.empty?
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# Check the current "catch" stack for the first one that is included in the
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# conflicts set. That is where the parent of the conflicting gem was required.
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# By jumping back to this spot, we can try other version of the parent of
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# the conflicting gem, hopefully finding a combination that activates correctly.
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@stack.reverse_each do |savepoint|
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if conflicts.include?(savepoint)
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debug { " -> Jumping to: #{savepoint}" }
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throw savepoint
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end
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end
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end
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end
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end
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def resolve_requirement(spec_group, requirement, reqs, activated)
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# We are going to try activating the spec. We need to keep track of stack of
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# requirements that got us to the point of activating this gem.
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spec_group.required_by.replace requirement.required_by
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spec_group.required_by << requirement
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activated[spec_group.name] = spec_group
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debug { " Activating: #{spec_group.name} (#{spec_group.version})" }
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debug { spec_group.required_by.map { |d| " * #{d.name} (#{d.requirement})" }.join("\n") }
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dependencies = spec_group.activate_platform(requirement.__platform)
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# Now, we have to loop through all child dependencies and add them to our
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# array of requirements.
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debug { " Dependencies"}
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dependencies.each do |dep|
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next if dep.type == :development
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debug { " * #{dep.name} (#{dep.requirement})" }
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dep.required_by.replace(requirement.required_by)
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dep.required_by << requirement
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reqs << dep
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end
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# We create a savepoint and mark it by the name of the requirement that caused
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# the gem to be activated. If the activated gem ever conflicts, we are able to
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# jump back to this point and try another version of the gem.
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length = @stack.length
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@stack << requirement.name
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retval = catch(requirement.name) do
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resolve(reqs, activated)
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end
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# Since we're doing a lot of throw / catches. A push does not necessarily match
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# up to a pop. So, we simply slice the stack back to what it was before the catch
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# block.
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@stack.slice!(length..-1)
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retval
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end
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def gems_size(dep)
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@gems_size[dep] ||= search(dep).size
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end
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def search(dep)
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if base = @base[dep.name] and base.any?
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reqs = [dep.requirement.as_list, base.first.version.to_s].flatten.compact
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d = Gem::Dependency.new(base.first.name, *reqs)
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else
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d = dep.dep
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end
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index = @source_requirements[d.name] || @index
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results = index.search_for_all_platforms(d, @base[d.name])
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if results.any?
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version = results.first.version
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nested = [[]]
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results.each do |spec|
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if spec.version != version
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nested << []
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version = spec.version
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end
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nested.last << spec
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end
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nested.map { |a| SpecGroup.new(a) }.select { |sg| sg.for?(dep.__platform) }
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else
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[]
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end
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end
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def clean_req(req)
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if req.to_s.include?(">= 0")
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req.to_s.gsub(/ \(.*?\)$/, '')
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else
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req.to_s.gsub(/\, (runtime|development)\)$/, ')')
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end
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end
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def version_conflict
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VersionConflict.new(errors.keys, error_message)
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end
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# For a given conflicted requirement, print out what exactly went wrong
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def gem_message(requirement)
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m = ""
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# A requirement that is required by itself is actually in the Gemfile, and does
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# not "depend on" itself
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if requirement.required_by.first && requirement.required_by.first.name != requirement.name
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m << " #{clean_req(requirement.required_by.first)} depends on\n"
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m << " #{clean_req(requirement)}\n"
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else
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m << " #{clean_req(requirement)}\n"
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end
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m << "\n"
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end
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def error_message
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errors.inject("") do |o, (conflict, (origin, requirement))|
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# origin is the SpecSet of specs from the Gemfile that is conflicted with
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if origin
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o << %{Bundler could not find compatible versions for gem "#{origin.name}":\n}
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o << " In Gemfile:\n"
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o << gem_message(requirement)
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# If the origin is "bundler", the conflict is us
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if origin.name == "bundler"
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o << " Current Bundler version:\n"
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newer_bundler_required = requirement.requirement > Gem::Requirement.new(origin.version)
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# If the origin is a LockfileParser, it does not respond_to :required_by
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elsif !origin.respond_to?(:required_by) || !(origin.required_by.first)
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o << " In snapshot (Gemfile.lock):\n"
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end
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o << gem_message(origin)
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# If the bundle wants a newer bundler than the running bundler, explain
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if origin.name == "bundler" && newer_bundler_required
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o << "Your version of Bundler is older than the one requested by the Gemfile.\n"
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o << "Perhaps you need to update Bundler by running `gem install bundler`."
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end
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# origin is nil if the required gem and version cannot be found in any of
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# the specified sources
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else
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# if the gem cannot be found because of a version conflict between lockfile and gemfile,
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# print a useful error that suggests running `bundle update`, which may fix things
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#
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# @base is a SpecSet of the gems in the lockfile
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# conflict is the name of the gem that could not be found
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if locked = @base[conflict].first
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o << "Bundler could not find compatible versions for gem #{conflict.inspect}:\n"
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o << " In snapshot (Gemfile.lock):\n"
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o << " #{clean_req(locked)}\n\n"
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o << " In Gemfile:\n"
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o << gem_message(requirement)
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o << "Running `bundle update` will rebuild your snapshot from scratch, using only\n"
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o << "the gems in your Gemfile, which may resolve the conflict.\n"
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# the rest of the time, the gem cannot be found because it does not exist in the known sources
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else
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if requirement.required_by.first
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o << "Could not find gem '#{clean_req(requirement)}', which is required by "
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o << "gem '#{clean_req(requirement.required_by.first)}', in any of the sources."
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else
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o << "Could not find gem '#{clean_req(requirement)} in any of the sources\n"
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end
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end
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end
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o
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end
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end
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end
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end
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