From 393c6529e228a805eaf91473fd768b8996325f60 Mon Sep 17 00:00:00 2001
From: binaryDiv <lexi@binarydiv.dev>
Date: Tue, 19 May 2026 20:08:50 +0200
Subject: [PATCH] shuriken: Implement header dependency detection

---
 tools/shuriken.py | 40 ++++++++++++++++++++++++++++------------
 1 file changed, 28 insertions(+), 12 deletions(-)

diff --git a/tools/shuriken.py b/tools/shuriken.py
index f65d5be..b7f38a7 100755
--- a/tools/shuriken.py
+++ b/tools/shuriken.py
@@ -600,7 +600,25 @@ class NinjaFileGenerator:
         config = self.config
         target = self.target
         target_config = self.target_config
-        build_dir = self.config.build_dir
+        build_dir = config.build_dir
+        ninja_file_path = config.get_ninja_file_path(config.default_target)
+        cpp_compiler = target_config.cpp_compiler
+
+        # Generate list of all source input files to be used as implicit dependencies for the dyndep file
+        dyndep_file_implicit_inputs = ' '.join(sorted(
+            t.src for t in self.compile_targets_cpp + self.compile_targets_cppm
+        ))
+
+        # Generate list of all .dep files that are generated implicitly during dyndep file generation.
+        # This is mostly necessary so that Ninja can create the directories for these files beforehand.
+        dyndep_file_implicit_outputs = ' '.join(sorted(
+            f'{t.obj}.dep' for t in self.compile_targets_cpp + self.compile_targets_cppm
+        ))
+
+        # Generate list of generated source files (currently just the copied std module file)
+        generated_source_files = ' '.join(sorted(
+            t.generated_src for t in self.compile_targets_std_module
+        ))
 
         # Generate Ninja file
         return f"""
@@ -626,19 +644,21 @@ rule copy
 
 # Rule to compile a .cpp file to a .o file
 rule cpp
-    command = {target_config.cpp_compiler} $cpp_flags -c $in -o $out
+    depfile = $out.dep
+    command = {cpp_compiler} $cpp_flags -MMD -MF $out.dep -c $in -o $out
 
 # Rule to compile a .cppm file (C++20 module) to a .o file ($out) and a .pcm file ($pcm_out)
 rule cppm
-    command = {target_config.cpp_compiler} $cpp_flags -c $in -o $out -fmodule-output=$pcm_out
+    depfile = $out.dep
+    command = {cpp_compiler} $cpp_flags -MMD -MF $out.dep -c $in -o $out -fmodule-output=$pcm_out
 
 # Rule to compile a standard library module to a .pcm file (e.g. "import std")
 rule std_module
-    command = {target_config.cpp_compiler} $cpp_std_module_flags --precompile $in -o $out
+    command = {cpp_compiler} $cpp_std_module_flags --precompile $in -o $out
 
 # Rule to link several .o files to an executable
 rule link
-    command = {target_config.cpp_compiler} $linker_flags -o $out $in $linker_args
+    command = {cpp_compiler} $linker_flags -o $out $in $linker_args
 
 # Rule to generate a compilation database (JSON file) from the build targets defined in a Ninja file
 rule generate_compdb
@@ -652,13 +672,13 @@ rule generate_dyndeps
 # -- STATIC BUILD TARGETS
 
 # Generate compilation database from default target Ninja file
-build $compdb_file: generate_compdb {self.config.get_ninja_file_path(config.default_target)} | generate_source_files
+build $compdb_file: generate_compdb {ninja_file_path} | generate_source_files
 
 # Shortcut alias to generate compilation database
 build compdb: phony $compdb_file
 
 # Generate Ninja dyndep file from compilation database
-build $dyndep_file: generate_dyndeps $compdb_file
+build $dyndep_file | {dyndep_file_implicit_outputs}: generate_dyndeps $compdb_file | {dyndep_file_implicit_inputs}
 
 
 # -- GENERATED BUILD TARGETS
@@ -668,17 +688,13 @@ build $builddir/{target_config.output_file}: link {' '.join(self.link_target_obj
 default $builddir/{target_config.output_file}
 
 # Phony target that depends on all generated source files
-build generate_source_files: phony {self.list_generated_source_files()}
+build generate_source_files: phony {generated_source_files}
 
 {self.render_compile_targets()}
 
 # End of build.{target}.ninja
 """.strip()
 
-    def list_generated_source_files(self) -> str:
-        generated_files = [target.generated_src for target in self.compile_targets_std_module]
-        return ' '.join(generated_files)
-
     def render_compile_targets(self) -> str:
         rendered_targets = list(map(self.render_compile_target_std_module, self.compile_targets_std_module))
         rendered_targets += list(map(self.render_compile_target_cpp, self.compile_targets_cpp))