From 408153aea03873a84d1a720107cf5ea1cc725913 Mon Sep 17 00:00:00 2001
From: Maximilian Downey Twiss <creatorsmithmdt@gmail.com>
Date: Tue, 16 Sep 2025 23:49:59 +1000
Subject: [PATCH] Prioritise runtime dependencies over build dependencies in
 tools/getrealdeps.rb (#12801)

---
 tests/tools/getrealdeps.rb | 47 ++++++++++++++++++++++++++++++++++++++
 tools/getrealdeps.rb       |  4 +++-
 2 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/tests/tools/getrealdeps.rb b/tests/tools/getrealdeps.rb
index 26ae49cd04..582af7685e 100644
--- a/tests/tools/getrealdeps.rb
+++ b/tests/tools/getrealdeps.rb
@@ -102,6 +102,30 @@ class GetRealDepsTest < Minitest::Test
     test_wrapper(input_file, expected_pkg_file, deps)
   end
 
+  def test_replace_build_dependency
+    deps = ['json_c']
+    input_file = <<~EOF
+      class Example < Package
+        binary_sha256({})
+
+        depends_on 'a2png'
+        depends_on 'json_c' => :build
+        depends_on 'lzlib'
+      end
+    EOF
+    expected_pkg_file = <<~EOF
+      class Example < Package
+        binary_sha256({})
+
+        depends_on 'a2png'
+        depends_on 'json_c' # R
+        depends_on 'lzlib'
+      end
+    EOF
+
+    test_wrapper(input_file, expected_pkg_file, deps)
+  end
+
   def test_add_special_dependency_to_empty
     deps = []
     input_file = <<~EOF
@@ -271,4 +295,27 @@ class GetRealDepsTest < Minitest::Test
 
     test_wrapper(input_file, expected_pkg_file, deps)
   end
+
+  def test_does_not_remove_build_dependency
+    deps = ['libspng']
+    input_file = <<~EOF
+      class Example < Package
+        binary_sha256({})
+
+        depends_on 'libmatroska'
+        depends_on 'ninja' => :build
+      end
+    EOF
+    expected_pkg_file = <<~EOF
+      class Example < Package
+        binary_sha256({})
+
+        depends_on 'libmatroska'
+        depends_on 'libspng' # R
+        depends_on 'ninja' => :build
+      end
+    EOF
+
+    test_wrapper(input_file, expected_pkg_file, deps)
+  end
 end
diff --git a/tools/getrealdeps.rb b/tools/getrealdeps.rb
index 7d52711be0..e7bcb25775 100755
--- a/tools/getrealdeps.rb
+++ b/tools/getrealdeps.rb
@@ -84,7 +84,6 @@ def write_deps(pkg_file, pkgdeps, pkg)
   end
 
   # Look for runtime dependencies that aren't already provided by the package.
-  # We do not convert build dependencies into runtime dependencies, because they are probably build dependencies for a good reason.
   missingpkgdeps = pkgdeps.reject { File.read(pkg_file).include?("depends_on '#{it}'") unless File.read(pkg_file).include?("depends_on '#{it}' => :build") }
 
   unless missingpkgdeps.empty?
@@ -108,6 +107,9 @@ def write_deps(pkg_file, pkgdeps, pkg)
   # Its unsafe to do this with other dependencies, because the packager might know something we don't.
   pkgdepsblock.delete_if { |line| line.match(/  depends_on '(.*)' # R/) { |matchdata| pkgdeps.none?(matchdata[1]) && !privileged_deps.include?(matchdata[1]) } }
 
+  # If a dependency is both a build and a runtime dependency, we remove the build dependency.
+  pkgdepsblock.delete_if { |line| line.match(/  depends_on '(.*)' => :build/) { |matchdata| missingpkgdeps.include?(matchdata[1]) } }
+
   # Remove any duplicate dependencies from the block.
   pkgdepsblock.uniq!