rename `std.Build.FileSource` to `std.Build.LazyPath`

[andrewrk]

zig/lib/std/Build.zig

Lines 1633 to 1634 in b9fc0d2

	/// A file source is a reference to an existing or future file.
	pub const FileSource = union(enum) {

It's not really a "file", is it? It could be a directory:

zig/lib/std/Build/Step/WriteFile.zig

Lines 128 to 132 in b9fc0d2

	/// Returns a `FileSource` representing the base directory that contains all the
	/// files from this `WriteFile`.
	pub fn getDirectorySource(wf: *WriteFile) std.Build.FileSource {
	return .{ .generated = &wf.generated_directory };
	}

"Source" is super confusing. Is it a source file? Not really, it could be an output artifact, or an input binary file.

The doc comment gives it away:

a reference to an existing or future file [or directory]

Therefore I propose:

-/// A file source is a reference to an existing or future file.
-pub const FileSource = union(enum) {
+/// A reference to an existing or future path.
+pub const LazyPath = union(enum) {

As well as all functions such as getOutputSource to getOutput. For that one in particular, let's make it getEmittedBin, corresponding to -femit-bin (related: #16351). Here is a full list of suggested renames:

-std/Build/Step/Run.zig:pub fn addFileSourceArg(self: *Run, file_source: std.Build.FileSource) void {
-std/Build/Step/Run.zig:pub fn addDirectorySourceArg(self: *Run, directory_source: std.Build.FileSource) void {
+std/Build/Step/Run.zig:pub fn addPathArg(self: *Run, path: std.Build.LazyPath) void {

-std/Build/Step/ObjCopy.zig:pub fn getOutputSource(self: *const ObjCopy) std.Build.FileSource {
+std/Build/Step/ObjCopy.zig:pub fn getOutput(self: *const ObjCopy) std.Build.LazyPath {

-std/Build/Step/ConfigHeader.zig:    pub fn getFileSource(style: Style) ?std.Build.FileSource {
+std/Build/Step/ConfigHeader.zig:    pub fn getTemplate(style: Style) ?std.Build.LazyPath {

-std/Build/Step/ConfigHeader.zig:pub fn getFileSource(self: *ConfigHeader) std.Build.FileSource {
+std/Build/Step/ConfigHeader.zig:pub fn getOutput(self: *ConfigHeader) std.Build.LazyPath {

-std/Build/Step/CheckObject.zig:pub fn checkNextFileSource(
+std/Build/Step/CheckObject.zig:pub fn checkNextPath(

-std/Build/Step/Options.zig:pub fn addOptionFileSource(
+std/Build/Step/Options.zig:pub fn addOptionPath(

-std/Build/Step/Options.zig:pub fn getSource(self: *Options) std.Build.FileSource {
+std/Build/Step/Options.zig:pub fn getOutput(self: *Options) std.Build.LazyPath {

-std/Build/Step/WriteFile.zig:    pub fn getFileSource(self: *File) std.Build.FileSource {
+std/Build/Step/WriteFile.zig:    pub fn getPath(self: *File) std.Build.LazyPath {

-std/Build/Step/WriteFile.zig:pub fn getDirectorySource(wf: *WriteFile) std.Build.FileSource {
+std/Build/Step/WriteFile.zig:pub fn getDirectory(wf: *WriteFile) std.Build.LazyPath {

-std/Build/Step/Compile.zig:pub fn addCSourceFile(self: *Compile, file: []const u8, flags: []const []const u8) void {
-std/Build/Step/Compile.zig:pub fn addCSourceFileSource(self: *Compile, source: CSourceFile) void {
+std/Build/Step/Compile.zig:pub fn addCSourceFile(self: *Compile, source: CSourceFile) void {

-std/Build/Step/Compile.zig:pub fn getOutputSource(self: *Compile) std.Build.FileSource {
+std/Build/Step/Compile.zig:pub fn getEmittedBin(self: *Compile) std.Build.LazyPath {

-std/Build/Step/Compile.zig:pub fn getOutputDirectorySource(self: *Compile) std.Build.FileSource {
+std/Build/Step/Compile.zig:pub fn getEmitDirectory(self: *Compile) std.Build.LazyPath {

-std/Build/Step/Compile.zig:pub fn getOutputLibSource(self: *Compile) std.Build.FileSource {
+std/Build/Step/Compile.zig:pub fn getEmittedImplib(self: *Compile) std.Build.LazyPath {

-std/Build/Step/Compile.zig:pub fn getOutputHSource(self: *Compile) std.Build.FileSource {
+std/Build/Step/Compile.zig:pub fn getEmittedH(self: *Compile) std.Build.LazyPath {

-std/Build/Step/Compile.zig:pub fn getOutputPdbSource(self: *Compile) std.Build.FileSource {
+std/Build/Step/Compile.zig:pub fn getEmittedPdb(self: *Compile) std.Build.LazyPath {

-std/Build/Step/Compile.zig:pub fn addAssemblyFileSource(self: *Compile, source: std.Build.FileSource) void {
+std/Build/Step/Compile.zig:pub fn addAssemblyFile(self: *Compile, source: std.Build.LazyPath) void {

-std/Build/Step/Compile.zig:pub fn addObjectFileSource(self: *Compile, source: std.Build.FileSource) void {
+std/Build/Step/Compile.zig:pub fn addObjectFile(self: *Compile, source: std.Build.LazyPath) void {

-std/Build/Step/Compile.zig:pub fn addLibraryPathDirectorySource(self: *Compile, directory_source: std.Build.FileSource) void {
+std/Build/Step/Compile.zig:pub fn addLibraryPath(self: *Compile, path: std.Build.LazyPath) void {

-std/Build/Step/Compile.zig:pub fn addRPathDirectorySource(self: *Compile, directory_source: std.Build.FileSource) void {
+std/Build/Step/Compile.zig:pub fn addRPath(self: *Compile, path: std.Build.LazyPath) void {

-std/Build/Step/Compile.zig:pub fn addFrameworkPathDirectorySource(self: *Compile, directory_source: std.Build.FileSource) void {
+std/Build/Step/Compile.zig:pub fn addFrameworkPath(self: *Compile, path: std.Build.LazyPath) void {

cc @MasterQ32 who originally introduced this crucial abstraction to the build system.

[ikskuh]

even if i dont really like LazyPath, i dont have a better name.
looks good to me!

If we perform this change, we maybe should remove the normal "path taking" functions, and also make include and lib dirs use lazypath, but we should add a convenience function for easy physical paths.

Something like

exe.addIncludePath(b.localPath("src/include"));
exe.addLibraryPath(Build.systemPath("/usr/include"));

would be very good for documentation

[andrewrk]

even if i dont really like LazyPath, i dont have a better name.

How about FuturePath?

If we perform this change, we maybe should remove the normal "path taking" functions, and also make include and lib dirs use lazypath, but we should add a convenience function for easy physical paths.

Agreed!

Although, it's a bit suspicious to hard code absolute paths to the system, isn't it? It seems to me the build script should merely ask for the system include directory, and then the build system should provide it via a combination of known system directories, and the --search-prefix flags supplied by the user of zig build.

I'm thinking more like this:

zig/lib/std/Build.zig

Lines 1368 to 1412 in 89396ff

	pub fn findProgram(self: *Build, names: []const []const u8, paths: []const []const u8) ![]const u8 {
	// TODO report error for ambiguous situations
	const exe_extension = @as(CrossTarget, .{}).exeFileExt();
	for (self.search_prefixes.items) |search_prefix| {
	for (names) |name| {
	if (fs.path.isAbsolute(name)) {
	return name;
	}
	const full_path = self.pathJoin(&.{
	search_prefix,
	"bin",
	self.fmt("{s}{s}", .{ name, exe_extension }),
	});
	return fs.realpathAlloc(self.allocator, full_path) catch continue;
	}
	}
	if (self.env_map.get("PATH")) |PATH| {
	for (names) |name| {
	if (fs.path.isAbsolute(name)) {
	return name;
	}
	var it = mem.tokenizeScalar(u8, PATH, fs.path.delimiter);
	while (it.next()) |path| {
	const full_path = self.pathJoin(&.{
	path,
	self.fmt("{s}{s}", .{ name, exe_extension }),
	});
	return fs.realpathAlloc(self.allocator, full_path) catch continue;
	}
	}
	}
	for (names) |name| {
	if (fs.path.isAbsolute(name)) {
	return name;
	}
	for (paths) |path| {
	const full_path = self.pathJoin(&.{
	path,
	self.fmt("{s}{s}", .{ name, exe_extension }),
	});
	return fs.realpathAlloc(self.allocator, full_path) catch continue;
	}
	}
	return error.FileNotFound;
	}

[ikskuh]

How about FuturePath?

Yeah i think this is more fitting. I mean, it's basically a Promise<Path> anyways, so we could also go with PathPromise.
After reading Futures and promises, it's definitly a FuturePath :)

Although, it's a bit suspicious to hard code absolute paths to the system, isn't it?

Yeah, but it's good for getting stuff up and running when dealing with several packages/tools that aren't on a remote yet and i don't copy-paste/link it into all my projects.

Imho system-wide paths should be supported for a good local-development experience, but that's up to you. the search prefix thing looks good.

[nektro]

LazyPath nomenclature has precedent in LazySrcLoc fwiw

[ikskuh]

trying to tackle that, going with LazyPath