Class | Gem::Version |
In: |
lib/rubygems/version.rb
|
Parent: | Object |
The Version class processes string versions into comparable values. A version string should normally be a series of numbers separated by periods. Each part (digits separated by periods) is considered its own number, and these are used for sorting. So for instance, 3.10 sorts higher than 3.2 because ten is greater than two.
If any part contains letters (currently only a-z are supported) then that version is considered prerelease. Versions with a prerelease part in the Nth part sort less than versions with N-1 parts. Prerelease parts are sorted alphabetically using the normal Ruby string sorting rules. If a prerelease part contains both letters and numbers, it will be broken into multiple parts to provide expected sort behavior (1.0.a10 becomes 1.0.a.10, and is greater than 1.0.a9).
Prereleases sort between real releases (newest to oldest):
Users expect to be able to specify a version constraint that gives them some reasonable expectation that new versions of a library will work with their software if the version constraint is true, and not work with their software if the version constraint is false. In other words, the perfect system will accept all compatible versions of the library and reject all incompatible versions.
Libraries change in 3 ways (well, more than 3, but stay focused here!).
Some examples are appropriate at this point. Suppose I have a Stack class that supports a push and a pop method.
Let‘s work through a project lifecycle using our Stack example from above.
Version 0.0.1: | The initial Stack class is release. |
Version 0.0.2: | Switched to a linked=list implementation because it is cooler. |
Version 0.1.0: | Added a depth method. |
Version 1.0.0: | Added top and made pop return nil (pop used to return the old top item). |
Version 1.1.0: | push now returns the value pushed (it used it return nil). |
Version 1.1.1: | Fixed a bug in the linked list implementation. |
Version 1.1.2: | Fixed a bug introduced in the last fix. |
Client A needs a stack with basic push/pop capability. He writes to the original interface (no top), so his version constraint looks like:
gem 'stack', '~> 0.0'
Essentially, any version is OK with Client A. An incompatible change to the library will cause him grief, but he is willing to take the chance (we call Client A optimistic).
Client B is just like Client A except for two things: (1) He uses the depth method and (2) he is worried about future incompatibilities, so he writes his version constraint like this:
gem 'stack', '~> 0.1'
The depth method was introduced in version 0.1.0, so that version or anything later is fine, as long as the version stays below version 1.0 where incompatibilities are introduced. We call Client B pessimistic because he is worried about incompatible future changes (it is OK to be pessimistic!).
From: blog.zenspider.com/2008/10/rubygems-howto-preventing-cata.html
Let‘s say you‘re depending on the fnord gem version 2.y.z. If you specify your dependency as ">= 2.0.0" then, you‘re good, right? What happens if fnord 3.0 comes out and it isn‘t backwards compatible with 2.y.z? Your stuff will break as a result of using ">=". The better route is to specify your dependency with a "spermy" version specifier. They‘re a tad confusing, so here is how the dependency specifiers work:
Specification From ... To (exclusive) ">= 3.0" 3.0 ... ∞ "~> 3.0" 3.0 ... 4.0 "~> 3.0.0" 3.0.0 ... 3.1 "~> 3.5" 3.5 ... 4.0 "~> 3.5.0" 3.5.0 ... 3.6
version | -> | to_s |
version | [R] | A string representation of this Version. |
True if the version string matches RubyGems’ requirements.
# File lib/rubygems/version.rb, line 160 160: def self.correct? version 161: version.to_s =~ ANCHORED_VERSION_PATTERN 162: end
Factory method to create a Version object. Input may be a Version or a String. Intended to simplify client code.
ver1 = Version.create('1.3.17') # -> (Version object) ver2 = Version.create(ver1) # -> (ver1) ver3 = Version.create(nil) # -> nil
# File lib/rubygems/version.rb, line 172 172: def self.create input 173: if input.respond_to? :version then 174: input 175: elsif input.nil? then 176: nil 177: else 178: new input 179: end 180: end
Constructs a Version from the version string. A version string is a series of digits or ASCII letters separated by dots.
# File lib/rubygems/version.rb, line 186 186: def initialize version 187: raise ArgumentError, "Malformed version number string #{version}" unless 188: self.class.correct?(version) 189: 190: @version = version.to_s 191: @version.strip! 192: end
Compares this version with other returning -1, 0, or 1 if the other version is larger, the same, or smaller than this one. Attempts to compare to something that‘s not a Gem::Version return nil.
# File lib/rubygems/version.rb, line 299 299: def <=> other 300: return unless Gem::Version === other 301: return 0 if @version == other.version 302: 303: lhsegments = segments 304: rhsegments = other.segments 305: 306: lhsize = lhsegments.size 307: rhsize = rhsegments.size 308: limit = (lhsize > rhsize ? lhsize : rhsize) - 1 309: 310: i = 0 311: 312: while i <= limit 313: lhs, rhs = lhsegments[i] || 0, rhsegments[i] || 0 314: i += 1 315: 316: next if lhs == rhs 317: return -1 if String === lhs && Numeric === rhs 318: return 1 if Numeric === lhs && String === rhs 319: 320: return lhs <=> rhs 321: end 322: 323: return 0 324: end
Return a new version object where the next to the last revision number is one greater (e.g., 5.3.1 => 5.4).
Pre-release (alpha) parts, e.g, 5.3.1.b.2 => 5.4, are ignored.
# File lib/rubygems/version.rb, line 200 200: def bump 201: segments = self.segments.dup 202: segments.pop while segments.any? { |s| String === s } 203: segments.pop if segments.size > 1 204: 205: segments[-1] = segments[-1].succ 206: self.class.new segments.join(".") 207: end
Dump only the raw version string, not the complete object. It‘s a string for backwards (RubyGems 1.3.5 and earlier) compatibility.
# File lib/rubygems/version.rb, line 229 229: def marshal_dump 230: [version] 231: end
Load custom marshal format. It‘s a string for backwards (RubyGems 1.3.5 and earlier) compatibility.
# File lib/rubygems/version.rb, line 237 237: def marshal_load array 238: initialize array[0] 239: end
A version is considered a prerelease if it contains a letter.
# File lib/rubygems/version.rb, line 250 250: def prerelease? 251: @prerelease ||= @version =~ /[a-zA-Z]/ 252: end
The release for this version (e.g. 1.2.0.a -> 1.2.0). Non-prerelease versions return themselves.
# File lib/rubygems/version.rb, line 262 262: def release 263: return self unless prerelease? 264: 265: segments = self.segments.dup 266: segments.pop while segments.any? { |s| String === s } 267: self.class.new segments.join('.') 268: end
A recommended version for use with a ~> Requirement.
# File lib/rubygems/version.rb, line 283 283: def spermy_recommendation 284: segments = self.segments.dup 285: 286: segments.pop while segments.any? { |s| String === s } 287: segments.pop while segments.size > 2 288: segments.push 0 while segments.size < 2 289: 290: "~> #{segments.join(".")}" 291: end