From 2b1f230d523ab46eff000ffcbc96acf75e57947c Mon Sep 17 00:00:00 2001
From: Antonio Paolillo <apaolill@gmail.com>
Date: Tue, 3 Feb 2026 09:25:06 +0100
Subject: [PATCH] examples/qemu: Make dependencies feature-aware

Refactor qemu_dependencies() to derive required Ubuntu packages from
QEMU --enable/--disable feature flags. Core build dependencies are
always included, while GUI, audio, docs, and tooling packages are
conditionally added based on the requested feature set.

Wire the new interface into qemu_builder() so dependency installation
matches the configured QEMU build options, reducing unnecessary
packages and image size.

Signed-off-by: Antonio Paolillo <apaolill@gmail.com>
---
 src/pythainer/examples/builders/__init__.py | 119 ++++++++++++++------
 1 file changed, 87 insertions(+), 32 deletions(-)

diff --git a/src/pythainer/examples/builders/__init__.py b/src/pythainer/examples/builders/__init__.py
index 241c8fc..d0747cf 100644
--- a/src/pythainer/examples/builders/__init__.py
+++ b/src/pythainer/examples/builders/__init__.py
@@ -519,53 +519,108 @@ def rust_builder(
     return builder
 
 
-def qemu_dependencies() -> List[str]:
+def qemu_dependencies(
+    enables: Tuple[str, ...] = (),
+    disables: Tuple[str, ...] = (),
+) -> List[str]:
     """
     Return the list of Ubuntu packages required to build QEMU from source.
 
-    These cover build tools (make, ninja), Python/sphinx for docs, GLib/pixman
-    for QEMU’s build/runtime, and optional GUI/audio backends (SDL2, GTK, ALSA, PulseAudio).
+    Core build packages are always included. Optional GUI/audio/docs packages
+    are included unless their corresponding feature is in ``disables``, or
+    excluded unless explicitly in ``enables``.
+
+    Parameters:
+        enables: QEMU features passed to ``--enable-*``.
+        disables: QEMU features passed to ``--disable-*``.
 
     Returns:
         List[str]: Package names to be installed prior to building QEMU.
     """
-    qemu_packages = [
-        "acpica-tools",
+
+    def _want(feature: str) -> bool:
+        """Return True if a feature is not explicitly disabled."""
+        if feature in disables:
+            return False
+        if feature in enables:
+            return True
+        # Default: include for backward compatibility
+        return True
+
+    packages = [
+        # Core build tools
+        "build-essential",
+        "diffutils",
         "libglib2.0-dev",
         "libpixman-1-dev",
-        "pkg-config",
-        "python3",
-        "python3-dev",
-        "python3-pip",
-        "python3-sphinx",
-        "python3-sphinx-rtd-theme",
-        "python3-venv",
-        "sparse",
-        "build-essential",
         "meson",
         "ninja-build",
         "pkg-config",
-        "diffutils",
         "python3",
+        "python3-dev",
         "python3-venv",
-        "libglib2.0-dev",
-        "libusb-1.0-0-dev",
-        "libncursesw5-dev",
-        "libpixman-1-dev",
-        "libepoxy-dev",
-        "libv4l-dev",
-        "libpng-dev",
-        "libsdl2-dev",
-        "libsdl2-image-dev",
-        "libgtk-3-dev",
-        "libgdk-pixbuf2.0-dev",
-        "libasound2-dev",
-        "libpulse-dev",
-        "libx11-dev",
-        "libslirp0",
     ]
 
-    return qemu_packages
+    if _want("docs"):
+        packages += [
+            "python3-sphinx",
+            "python3-sphinx-rtd-theme",
+        ]
+
+    if _want("sdl"):
+        packages += [
+            "libsdl2-dev",
+            "libsdl2-image-dev",
+        ]
+
+    if _want("gtk"):
+        packages += [
+            "libepoxy-dev",
+            "libgdk-pixbuf2.0-dev",
+            "libgtk-3-dev",
+            "libx11-dev",
+        ]
+
+    if _want("opengl"):
+        packages += [
+            "libepoxy-dev",
+        ]
+
+    if _want("slirp"):
+        packages += [
+            "libslirp0",
+        ]
+
+    if _want("guest-agent") or _want("tools"):
+        packages += [
+            "acpica-tools",
+            "libusb-1.0-0-dev",
+        ]
+
+    if _want("vnc"):
+        packages += [
+            "libpng-dev",
+        ]
+
+    if _want("curses"):
+        packages += [
+            "libncursesw5-dev",
+        ]
+
+    if _want("pa"):
+        packages += [
+            "libpulse-dev",
+            "libasound2-dev",
+        ]
+
+    if _want("alsa"):
+        packages += [
+            "libasound2-dev",
+        ]
+
+    # Deduplicate while preserving order
+    seen: set = set()
+    return [p for p in packages if not (p in seen or seen.add(p))]
 
 
 def qemu_builder(
@@ -601,7 +656,7 @@ def qemu_builder(
     builder = PartialDockerBuilder()
 
     builder.root()
-    builder.add_packages(packages=qemu_dependencies())
+    builder.add_packages(packages=qemu_dependencies(enables=enables, disables=disables))
     builder.user()
 
     builder.run_multiple(