Introduce tag for implicit dependencies

Library/Homebrew/cmd/deps.rb

@@ -191,6 +191,7 @@ module Homebrew
       str = "#{str} [test]" if dep.test?
       str = "#{str} [optional]" if dep.optional?
       str = "#{str} [recommended]" if dep.recommended?
+      str = "#{str} [implicit]" if dep.implicit?
     end
 
     str

Library/Homebrew/dependable.rb

@@ -9,7 +9,7 @@ require "options"
 module Dependable
   # `:run` and `:linked` are no longer used but keep them here to avoid their
   # misuse in future.
-  RESERVED_TAGS = [:build, :optional, :recommended, :run, :test, :linked].freeze
+  RESERVED_TAGS = [:build, :optional, :recommended, :run, :test, :linked, :implicit].freeze
 
   attr_reader :tags
 
@@ -29,6 +29,10 @@ module Dependable
     tags.include? :test
   end
 
+  def implicit?
+    tags.include? :implicit
+  end
+
   def required?
     !build? && !test? && !optional? && !recommended?
   end

Library/Homebrew/dependency.rb

@@ -180,9 +180,14 @@ class Dependency
         option_names = deps.flat_map(&:option_names).uniq
         kwargs = {}
         kwargs[:bounds] = dep.bounds if dep.uses_from_macos?
+        # TODO: simpify to just **kwargs when we require Ruby >= 2.7
+        if kwargs.empty?
+          dep.class.new(name, tags, dep.env_proc, option_names)
+        else
           dep.class.new(name, tags, dep.env_proc, option_names, **kwargs)
         end
       end
+    end
 
     private
 
@@ -208,10 +213,10 @@ class Dependency
     end
 
     def merge_temporality(deps)
-      # Means both build and runtime dependency.
+      new_tags = []
-      return [] unless deps.all?(&:build?)
+      new_tags << :build if deps.all?(&:build?)
-
+      new_tags << :implicit if deps.all?(&:implicit?)
-      [:build]
+      new_tags
     end
   end
 end

Library/Homebrew/dependency_collector.rb

@@ -84,37 +84,37 @@ class DependencyCollector
   def git_dep_if_needed(tags)
     return if Utils::Git.available?
 
-    Dependency.new("git", tags)
+    Dependency.new("git", [*tags, :implicit])
   end
 
   def curl_dep_if_needed(tags)
-    Dependency.new("curl", tags)
+    Dependency.new("curl", [*tags, :implicit])
   end
 
   def subversion_dep_if_needed(tags)
     return if Utils::Svn.available?
 
-    Dependency.new("subversion", tags)
+    Dependency.new("subversion", [*tags, :implicit])
   end
 
   def cvs_dep_if_needed(tags)
-    Dependency.new("cvs", tags) unless which("cvs")
+    Dependency.new("cvs", [*tags, :implicit]) unless which("cvs")
   end
 
   def xz_dep_if_needed(tags)
-    Dependency.new("xz", tags) unless which("xz")
+    Dependency.new("xz", [*tags, :implicit]) unless which("xz")
   end
 
   def zstd_dep_if_needed(tags)
-    Dependency.new("zstd", tags) unless which("zstd")
+    Dependency.new("zstd", [*tags, :implicit]) unless which("zstd")
   end
 
   def unzip_dep_if_needed(tags)
-    Dependency.new("unzip", tags) unless which("unzip")
+    Dependency.new("unzip", [*tags, :implicit]) unless which("unzip")
   end
 
   def bzip2_dep_if_needed(tags)
-    Dependency.new("bzip2", tags) unless which("bzip2")
+    Dependency.new("bzip2", [*tags, :implicit]) unless which("bzip2")
   end
 
   def self.tar_needs_xz_dependency?
@@ -127,6 +127,8 @@ class DependencyCollector
   def init_global_dep_tree_if_needed!; end
 
   def parse_spec(spec, tags)
+    raise ArgumentError, "Implicit dependencies cannot be manually specified" if tags.include?(:implicit)
+
     case spec
     when String
       parse_string_spec(spec, tags)
@@ -184,11 +186,11 @@ class DependencyCollector
     elsif strategy <= SubversionDownloadStrategy
       subversion_dep_if_needed(tags)
     elsif strategy <= MercurialDownloadStrategy
-      Dependency.new("mercurial", tags)
+      Dependency.new("mercurial", [*tags, :implicit])
     elsif strategy <= FossilDownloadStrategy
-      Dependency.new("fossil", tags)
+      Dependency.new("fossil", [*tags, :implicit])
     elsif strategy <= BazaarDownloadStrategy
-      Dependency.new("breezy", tags)
+      Dependency.new("breezy", [*tags, :implicit])
     elsif strategy <= CVSDownloadStrategy
       cvs_dep_if_needed(tags)
     elsif strategy < AbstractDownloadStrategy
@@ -204,10 +206,10 @@ class DependencyCollector
     when ".zst"         then zstd_dep_if_needed(tags)
     when ".zip"         then unzip_dep_if_needed(tags)
     when ".bz2"         then bzip2_dep_if_needed(tags)
-    when ".lha", ".lzh" then Dependency.new("lha", tags)
+    when ".lha", ".lzh" then Dependency.new("lha", [*tags, :implicit])
-    when ".lz"          then Dependency.new("lzip", tags)
+    when ".lz"          then Dependency.new("lzip", [*tags, :implicit])
-    when ".rar"         then Dependency.new("libarchive", tags)
+    when ".rar"         then Dependency.new("libarchive", [*tags, :implicit])
-    when ".7z"          then Dependency.new("p7zip", tags)
+    when ".7z"          then Dependency.new("p7zip", [*tags, :implicit])
     end
   end
 end

Library/Homebrew/extend/os/linux/dependency_collector.rb

@@ -17,7 +17,7 @@ class DependencyCollector
     return if global_dep_tree[GCC]&.intersect?(related_formula_names)
     return unless formula_for(GCC)
 
-    Dependency.new(GCC)
+    Dependency.new(GCC, [:implicit])
   end
 
   sig { params(related_formula_names: T::Set[String]).returns(T.nilable(Dependency)) }
@@ -28,7 +28,7 @@ class DependencyCollector
     return if global_dep_tree[GLIBC]&.intersect?(related_formula_names)
     return unless formula_for(GLIBC)
 
-    Dependency.new(GLIBC)
+    Dependency.new(GLIBC, [:implicit])
   end
 
   private

Library/Homebrew/extend/os/mac/dependency_collector.rb

@@ -8,11 +8,11 @@ class DependencyCollector
   def git_dep_if_needed(tags); end
 
   def subversion_dep_if_needed(tags)
-    Dependency.new("subversion", tags)
+    Dependency.new("subversion", [*tags, :implicit])
   end
 
   def cvs_dep_if_needed(tags)
-    Dependency.new("cvs", tags)
+    Dependency.new("cvs", [*tags, :implicit])
   end
 
   def xz_dep_if_needed(tags); end

Library/Homebrew/test/dependency_collector_spec.rb

@@ -52,13 +52,13 @@ describe DependencyCollector do
     it "creates a resource dependency from a CVS URL" do
       resource = Resource.new
       resource.url(":pserver:anonymous:@brew.sh:/cvsroot/foo/bar", using: :cvs)
-      expect(collector.add(resource)).to eq(Dependency.new("cvs", [:build, :test]))
+      expect(collector.add(resource)).to eq(Dependency.new("cvs", [:build, :test, :implicit]))
     end
 
     it "creates a resource dependency from a '.7z' URL" do
       resource = Resource.new
       resource.url("https://brew.sh/foo.7z")
-      expect(collector.add(resource)).to eq(Dependency.new("p7zip", [:build, :test]))
+      expect(collector.add(resource)).to eq(Dependency.new("p7zip", [:build, :test, :implicit]))
     end
 
     it "creates a resource dependency from a '.gz' URL" do
@@ -70,25 +70,25 @@ describe DependencyCollector do
     it "creates a resource dependency from a '.lz' URL" do
       resource = Resource.new
       resource.url("https://brew.sh/foo.lz")
-      expect(collector.add(resource)).to eq(Dependency.new("lzip", [:build, :test]))
+      expect(collector.add(resource)).to eq(Dependency.new("lzip", [:build, :test, :implicit]))
     end
 
     it "creates a resource dependency from a '.lha' URL" do
       resource = Resource.new
       resource.url("https://brew.sh/foo.lha")
-      expect(collector.add(resource)).to eq(Dependency.new("lha", [:build, :test]))
+      expect(collector.add(resource)).to eq(Dependency.new("lha", [:build, :test, :implicit]))
     end
 
     it "creates a resource dependency from a '.lzh' URL" do
       resource = Resource.new
       resource.url("https://brew.sh/foo.lzh")
-      expect(collector.add(resource)).to eq(Dependency.new("lha", [:build, :test]))
+      expect(collector.add(resource)).to eq(Dependency.new("lha", [:build, :test, :implicit]))
     end
 
     it "creates a resource dependency from a '.rar' URL" do
       resource = Resource.new
       resource.url("https://brew.sh/foo.rar")
-      expect(collector.add(resource)).to eq(Dependency.new("libarchive", [:build, :test]))
+      expect(collector.add(resource)).to eq(Dependency.new("libarchive", [:build, :test, :implicit]))
     end
 
     it "raises a TypeError for unknown classes" do

Library/Homebrew/test/os/linux/dependency_collector_spec.rb

@@ -14,19 +14,19 @@ describe DependencyCollector do
       it "creates a resource dependency from a '.xz' URL" do
         resource.url("https://brew.sh/foo.xz")
         allow_any_instance_of(Object).to receive(:which).with("xz")
-        expect(collector.add(resource)).to eq(Dependency.new("xz", [:build, :test]))
+        expect(collector.add(resource)).to eq(Dependency.new("xz", [:build, :test, :implicit]))
       end
 
       it "creates a resource dependency from a '.zip' URL" do
         resource.url("https://brew.sh/foo.zip")
         allow_any_instance_of(Object).to receive(:which).with("unzip")
-        expect(collector.add(resource)).to eq(Dependency.new("unzip", [:build, :test]))
+        expect(collector.add(resource)).to eq(Dependency.new("unzip", [:build, :test, :implicit]))
       end
 
       it "creates a resource dependency from a '.bz2' URL" do
         resource.url("https://brew.sh/foo.tar.bz2")
         allow_any_instance_of(Object).to receive(:which).with("bzip2")
-        expect(collector.add(resource)).to eq(Dependency.new("bzip2", [:build, :test]))
+        expect(collector.add(resource)).to eq(Dependency.new("bzip2", [:build, :test, :implicit]))
       end
     end
 

Library/Homebrew/test/os/mac/dependency_collector_spec.rb

@@ -34,6 +34,6 @@ describe DependencyCollector do
   specify "Resource dependency from a Subversion URL" do
     resource = Resource.new
     resource.url("svn://brew.sh/foo/bar")
-    expect(collector.add(resource)).to eq(Dependency.new("subversion", [:build, :test]))
+    expect(collector.add(resource)).to eq(Dependency.new("subversion", [:build, :test, :implicit]))
   end
 end