add Utils::Git.relative_to_root method to return source file paths re…

…lative to git repo's root

lib/datadog/ci/utils/git.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require "open3"
+require "pathname"
 
 module Datadog
   module CI
@@ -25,6 +26,18 @@ def self.root
           @@root = exec_git_command("git rev-parse --show-toplevel")
         end
 
+        def self.relative_to_root(path)
+          return nil if path.nil?
+
+          git_root = root
+          return path if git_root.nil?
+
+          path = Pathname.new(File.expand_path(path))
+          git_root = Pathname.new(git_root)
+
+          path.relative_path_from(git_root).to_s
+        end
+
         def self.exec_git_command(cmd)
           out, status = Open3.capture2e(cmd)
 

sig/datadog/ci/utils/git.rbs

@@ -4,11 +4,15 @@ module Datadog
       module Git
         @@root: String?
 
-        def self?.normalize_ref: (untyped name) -> (nil | untyped)
+        def self.normalize_ref: (String? name) -> String?
 
-        def self?.is_git_tag?: (untyped ref) -> untyped
+        def self.is_git_tag?: (String? ref) -> bool
 
         def self.exec_git_command: (String ref) -> String?
+
+        def self.root: -> String?
+
+        def self.relative_to_root: (String? path) -> String?
       end
     end
   end

spec/datadog/ci/utils/git_spec.rb

@@ -64,4 +64,45 @@
       end
     end
   end
+
+  describe ".relative_to_root" do
+    subject { described_class.relative_to_root(path) }
+
+    context "when path is nil" do
+      let(:path) { nil }
+
+      it { is_expected.to be_nil }
+    end
+
+    context "when git root is nil" do
+      before do
+        allow(described_class).to receive(:root).and_return(nil)
+      end
+
+      let(:path) { "foo/bar" }
+
+      it { is_expected.to eq("foo/bar") }
+    end
+
+    context "when git root is not nil" do
+      context "when path is absolute" do
+        before do
+          allow(described_class).to receive(:root).and_return("/foo/bar")
+        end
+        let(:path) { "/foo/bar/baz" }
+
+        it { is_expected.to eq("baz") }
+      end
+
+      context "when path is relative" do
+        before do
+          allow(described_class).to receive(:root).and_return("#{Dir.pwd}/foo/bar")
+        end
+
+        let(:path) { "./baz" }
+
+        it { is_expected.to eq("../../baz") }
+      end
+    end
+  end
 end