Support intersection of versions

SPEC.md

@@ -167,8 +167,9 @@ A version requirement (String).
 - It may be a version number.
 - It may be `"*"` if any version will do.
 - The version number may be prefixed by an operator: `<`, `<=`, `>`, `>=` or `~>`.
+- Multiple requirements can be separated by commas.
 
-Examples: `1.2.3`, `>= 1.0.0` or `~> 2.0`.
+Examples: `1.2.3`, `>= 1.0.0`, `>= 1.0.0, < 2.0` or `~> 2.0`.
 
 Most of the version operators, like `>= 1.0.0`, are self-explanatory, but
 the `~>` operator has a special meaning, best shown by example:

spec/integration/install_spec.cr

@@ -41,6 +41,14 @@ describe "install" do
     end
   end
 
+  it "resolves intersection" do
+    metadata = {dependencies: {web: ">= 1.1.0, < 2.0"}}
+    with_shard(metadata) do
+      run "shards install"
+      assert_installed "web", "1.2.0"
+    end
+  end
+
   it "fails when spec is missing" do
     Dir.cd(application_path) do
       ex = expect_raises(FailedCommand) { run "shards install --no-color" }

spec/unit/version_req_spec.cr

@@ -0,0 +1,23 @@
+require "./spec_helper"
+
+module Shards
+  describe VersionReq do
+    it "parses" do
+      VersionReq.new("~> 1.0").patterns.should eq(["~> 1.0"])
+      VersionReq.new("~> 1.0, < 1.8").patterns.should eq(["~> 1.0", "< 1.8"])
+      VersionReq.new("~> 1.0,, < 1.8").patterns.should eq(["~> 1.0", "< 1.8"])
+    end
+
+    it "to_s" do
+      VersionReq.new("~> 1.0").to_s.should eq("~> 1.0")
+      VersionReq.new("~> 1.0,< 1.8").to_s.should eq("~> 1.0, < 1.8")
+    end
+
+    it "prerelease?" do
+      VersionReq.new("~> 1.0").prerelease?.should be_false
+      VersionReq.new("~> 1.0-a").prerelease?.should be_true
+      VersionReq.new("~> 1.0, < 1.8").prerelease?.should be_false
+      VersionReq.new("~> 1.0, < 1.8-a").prerelease?.should be_true
+    end
+  end
+end

spec/unit/versions_spec.cr

@@ -185,6 +185,12 @@ module Shards
       resolve(["0.1"], "~> 0.1.0").should eq(["0.1"])
     end
 
+    it "resolve intersection" do
+      versions = %w(0.0.1 0.1.0 0.1.1 0.1.2 0.2.0 0.10.0)
+
+      resolve(versions, ">= 0.1.0, < 0.2.0").should eq(["0.1.0", "0.1.1", "0.1.2"])
+    end
+
     it "matches?" do
       matches?("0.1.0", "*").should be_true
       matches?("1.0.0", "*").should be_true
@@ -218,6 +224,9 @@ module Shards
       matches?("1.0.0", "~> 1.1").should be_false
       matches?("1.0.1", "~> 1.0.0").should be_true
       matches?("1.0.0", "~> 1.0.1").should be_false
+
+      matches?("1.0.0", "> 0.1.0, < 1.0.1").should be_true
+      matches?("1.0.1", "> 0.1.0, < 1.0.1").should be_false
     end
   end
 end

src/dependency.cr

@@ -40,7 +40,7 @@ module Shards
         resolver = resolver_data[:type].find_resolver(resolver_data[:key], name, resolver_data[:source])
         requirement = resolver.parse_requirement(params)
         if is_lock && requirement.is_a?(VersionReq)
-          requirement = Version.new(requirement.pattern)
+          requirement = Version.new(requirement.to_s)
         end
 
         Dependency.new(name, resolver, requirement)

src/requirement.cr

@@ -1,21 +1,24 @@
 module Shards
   struct VersionReq
-    getter pattern : String
+    getter patterns : Array(String)
 
-    def initialize(@pattern)
+    def initialize(patterns)
+      @patterns = patterns.split(',', remove_empty: true).map &.strip
     end
 
     def prerelease?
-      Versions.prerelease? @pattern
+      patterns.any? do |pattern|
+        Versions.prerelease? pattern
+      end
     end
 
     def to_s(io)
-      io << pattern
+      patterns.join(", ", io)
     end
 
     def to_yaml(yaml)
       yaml.scalar "version"
-      yaml.scalar @pattern
+      yaml.scalar to_s
     end
   end
 

src/versions.cr

@@ -167,16 +167,17 @@ module Shards
     end
 
     def self.resolve(versions : Array(Version), requirement : VersionReq)
-      case requirement.pattern
-      when "*", ""
-        versions
-      else
-        versions.select { |version| matches?(version, requirement) }
-      end
+      versions.select { |version| matches?(version, requirement) }
     end
 
     def self.matches?(version : Version, requirement : VersionReq)
-      case requirement.pattern
+      requirement.patterns.all? do |pattern|
+        matches_single_pattern?(version, pattern)
+      end
+    end
+
+    private def self.matches_single_pattern?(version : Version, pattern : String)
+      case pattern
       when "*", ""
         true
       when /~>\s*([^\s]+)\d*/
@@ -189,7 +190,7 @@ module Shards
       when /\s*(~>|>=|<=|>|<|=)\s*([^~<>=\s]+)\s*/
         matches_operator?(version.value, $1, $2)
       else
-        matches_operator?(version.value, "=", requirement.pattern)
+        matches_operator?(version.value, "=", pattern)
       end
     end