language: add php shebang module

Signed-off-by: botantony <antonsm21@gmail.com>

Library/Homebrew/language/php.rb

@@ -0,0 +1,43 @@
+# typed: strict
+# frozen_string_literal: true
+
+module Language
+  # Helper functions for PHP formulae.
+  #
+  # @api public
+  module PHP
+    # Helper module for replacing `php` shebangs.
+    module Shebang
+      extend T::Helpers
+
+      requires_ancestor { Formula }
+
+      module_function
+
+      # A regex to match potential shebang permutations.
+      PHP_SHEBANG_REGEX = %r{^#! ?(?:/usr/bin/(?:env )?)?php( |$)}
+
+      # The length of the longest shebang matching `SHEBANG_REGEX`.
+      PHP_SHEBANG_MAX_LENGTH = T.let("#! /usr/bin/env php ".length, Integer)
+
+      # @private
+      sig { params(php_path: T.any(String, Pathname)).returns(Utils::Shebang::RewriteInfo) }
+      def php_shebang_rewrite_info(php_path)
+        Utils::Shebang::RewriteInfo.new(
+          PHP_SHEBANG_REGEX,
+          PHP_SHEBANG_MAX_LENGTH,
+          "#{php_path}\\1",
+        )
+      end
+
+      sig { params(formula: Formula).returns(Utils::Shebang::RewriteInfo) }
+      def detected_php_shebang(formula = T.cast(self, Formula))
+        php_deps = formula.deps.select(&:required?).map(&:name).grep(/^php(@.+)?$/)
+        raise ShebangDetectionError.new("PHP", "formula does not depend on PHP") if php_deps.empty?
+        raise ShebangDetectionError.new("PHP", "formula has multiple PHP dependencies") if php_deps.length > 1
+
+        php_shebang_rewrite_info(Formula[php_deps.first].opt_bin/"php")
+      end
+    end
+  end
+end

Library/Homebrew/test/language/php/shebang_spec.rb

@@ -0,0 +1,91 @@
+# frozen_string_literal: true
+
+require "language/php"
+require "utils/shebang"
+
+RSpec.describe Language::PHP::Shebang do
+  let(:file) { Tempfile.new("php-shebang") }
+  let(:broken_file) { Tempfile.new("php-shebang") }
+  let(:f) do
+    f = {}
+
+    f[:php81] = formula "php@8.1" do
+      url "https://brew.sh/node-18.0.0.tgz"
+    end
+
+    f[:versioned_php_dep] = formula "foo" do
+      url "https://brew.sh/foo-1.0.tgz"
+
+      depends_on "php@8.1"
+    end
+
+    f[:no_deps] = formula "foo" do
+      url "https://brew.sh/foo-1.0.tgz"
+    end
+
+    f[:multiple_deps] = formula "foo" do
+      url "https://brew.sh/foo-1.0.tgz"
+
+      depends_on "php"
+      depends_on "php@8.1"
+    end
+
+    f
+  end
+
+  before do
+    file.write <<~EOS
+      #!/usr/bin/env php
+      a
+      b
+      c
+    EOS
+    file.flush
+
+    broken_file.write <<~EOS
+      #!php
+      a
+      b
+      c
+    EOS
+    broken_file.flush
+  end
+
+  after { [file, broken_file].each(&:unlink) }
+
+  describe "#detected_php_shebang" do
+    it "can be used to replace PHP shebangs" do
+      allow(Formulary).to receive(:factory).with(f[:php81].name).and_return(f[:php81])
+      Utils::Shebang.rewrite_shebang described_class.detected_php_shebang(f[:versioned_php_dep]), file.path
+
+      expect(File.read(file)).to eq <<~EOS
+        #!#{HOMEBREW_PREFIX/"opt/php@8.1/bin/php"}
+        a
+        b
+        c
+      EOS
+    end
+
+    it "can fix broken shebang like `#!php`" do
+      allow(Formulary).to receive(:factory).with(f[:php81].name).and_return(f[:php81])
+      Utils::Shebang.rewrite_shebang described_class.detected_php_shebang(f[:versioned_php_dep]), broken_file.path
+
+      expect(File.read(broken_file)).to eq <<~EOS
+        #!#{HOMEBREW_PREFIX/"opt/php@8.1/bin/php"}
+        a
+        b
+        c
+      EOS
+    end
+
+    it "errors if formula doesn't depend on PHP" do
+      expect { Utils::Shebang.rewrite_shebang described_class.detected_php_shebang(f[:no_deps]), file.path }
+        .to raise_error(ShebangDetectionError, "Cannot detect PHP shebang: formula does not depend on PHP.")
+    end
+
+    it "errors if formula depends on more than one php" do
+      expect { Utils::Shebang.rewrite_shebang described_class.detected_php_shebang(f[:multiple_deps]), file.path }
+        .to raise_error(ShebangDetectionError, "Cannot detect PHP shebang: formula has multiple PHP dependencies.")
+    end
+  end
+end