From c7df14c38a87ceca13df47fa700d3f9fa250be91 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Wed, 10 Nov 2021 20:06:23 +0200
Subject: [PATCH] Save caches before starting the build

This causes the config cache file's timestamp to be earlier than any
built file, preventing a spurious second rebuild after changing options.
---
 source/builder.cpp    | 14 +++++++-------
 source/builder.h      |  3 +++
 source/buildercli.cpp |  7 +++++++
 source/cache.cpp      |  2 ++
 source/cache.h        |  2 +-
 source/config.cpp     |  2 ++
 source/config.h       |  2 +-
 7 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/source/builder.cpp b/source/builder.cpp
index 65d7da4..e26c115 100644
--- a/source/builder.cpp
+++ b/source/builder.cpp
@@ -169,6 +169,13 @@ void Builder::load_build_file(const FS::Path &fn, const Config::InputOptions *op
 	loader.load(parser);
 }
 
+void Builder::save_caches()
+{
+	const PackageManager::PackageMap &packages = package_manager.get_packages();
+	for(PackageManager::PackageMap::const_iterator i=packages.begin(); i!=packages.end(); ++i)
+		i->second->save_caches();
+}
+
 int Builder::build(unsigned jobs, bool dry_run, bool show_progress)
 {
 	unsigned total = build_graph.count_rebuild_targets();
@@ -256,13 +263,6 @@ int Builder::build(unsigned jobs, bool dry_run, bool show_progress)
 	else if(show_progress)
 		get_logger().log("summary", "Build complete");
 
-	if(!dry_run)
-	{
-		const PackageManager::PackageMap &packages = package_manager.get_packages();
-		for(PackageManager::PackageMap::const_iterator i=packages.begin(); i!=packages.end(); ++i)
-			i->second->save_caches();
-	}
-
 	return fail;
 }
 
diff --git a/source/builder.h b/source/builder.h
index 9ea6677..70ca861 100644
--- a/source/builder.h
+++ b/source/builder.h
@@ -95,6 +95,9 @@ public:
 	configured. */
 	void load_build_file(const Msp::FS::Path &, const Config::InputOptions *opts = 0, bool all = false);
 
+	/** Saves package configuration and dependency caches. */
+	void save_caches();
+
 	/** Builds the goal targets.  The build graph must be prepared first. */
 	int build(unsigned jobs = 1, bool dry_run = false, bool show_progress = false);
 
diff --git a/source/buildercli.cpp b/source/buildercli.cpp
index a37336f..0a84364 100644
--- a/source/buildercli.cpp
+++ b/source/buildercli.cpp
@@ -191,7 +191,11 @@ int BuilderCLI::main()
 {
 	FS::Path main_file = cwd/build_file;
 	if(FS::exists(main_file))
+	{
 		builder.load_build_file(main_file, &cmdline_options, conf_all);
+		if(!dry_run && !cmdline_options.empty())
+			builder.save_caches();
+	}
 	else if(!help)
 	{
 		IO::print(IO::cerr, "The file %s does not exist.\n", main_file);
@@ -286,6 +290,9 @@ int BuilderCLI::main()
 	if(build)
 		exit_code = builder.build(jobs, dry_run, show_progress);
 
+	if(!dry_run)
+		builder.save_caches();
+
 	return exit_code;
 }
 
diff --git a/source/cache.cpp b/source/cache.cpp
index a2d6824..de4643c 100644
--- a/source/cache.cpp
+++ b/source/cache.cpp
@@ -149,4 +149,6 @@ void Cache::save() const
 		for(ValueList::const_iterator j=i->second.begin(); j!=i->second.end(); ++j)
 			write_string(out, *j);
 	}
+
+	changed = false;
 }
diff --git a/source/cache.h b/source/cache.h
index 95ae4fb..69025fd 100644
--- a/source/cache.h
+++ b/source/cache.h
@@ -29,7 +29,7 @@ private:
 	Msp::FS::Path filename;
 	DataMap data;
 	Msp::Time::TimeStamp mtime;
-	bool changed;
+	mutable bool changed;
 
 public:
 	Cache(SourcePackage &p);
diff --git a/source/config.cpp b/source/config.cpp
index 69abe9d..36e7870 100644
--- a/source/config.cpp
+++ b/source/config.cpp
@@ -84,6 +84,8 @@ void Config::save() const
 
 	for(OptionMap::const_iterator i=options.begin(); i!=options.end(); ++i)
 		IO::print(out, "option \"%s\" \"%s\";\n", i->second.name, i->second.value);
+
+	changed = false;
 }
 
 
diff --git a/source/config.h b/source/config.h
index 1f7fa71..3257794 100644
--- a/source/config.h
+++ b/source/config.h
@@ -41,7 +41,7 @@ private:
 	OptionMap options;
 	InputOptions pending_options;
 	Msp::Time::TimeStamp mtime;
-	bool changed;
+	mutable bool changed;
 
 public:
 	Config(SourcePackage &);
-- 
2.45.2