Function lazyDependency [src]

When this function is called, it means that the current build does, in fact, require this dependency. If the dependency is already fetched, it proceeds in the same manner as dependency. However if the dependency was not fetched, then when the build script is finished running, the build will not proceed to the make phase. Instead, the parent process will additionally fetch all the lazy dependencies that were actually required by running the build script, rebuild the build script, and then run it again. In other words, if this function returns null it means that the only purpose of completing the configure phase is to find out all the other lazy dependencies that are also required. It is allowed to use this function for non-lazy dependencies, in which case it will never return null. This allows toggling laziness via build.zig.zon without changing build.zig logic.

Prototype

pub fn lazyDependency(b: *Build, name: []const u8, args: anytype) ?*Dependency

Parameters

b: *Buildname: []const u8

Source

  pub fn lazyDependency(b: *Build, name: []const u8, args: anytype) ?*Dependency {
    const build_runner = @import("root");
    const deps = build_runner.dependencies;
    const pkg_hash = findPkgHashOrFatal(b, name);

    inline for (@typeInfo(deps.packages).@"struct".decls) |decl| {
        if (mem.eql(u8, decl.name, pkg_hash)) {
            const pkg = @field(deps.packages, decl.name);
            const available = !@hasDecl(pkg, "available") or pkg.available;
            if (!available) {
                markNeededLazyDep(b, pkg_hash);
                return null;
            }
            return dependencyInner(b, name, pkg.build_root, if (@hasDecl(pkg, "build_zig")) pkg.build_zig else null, pkg_hash, pkg.deps, args);
        }
    }

    unreachable; // Bad @dependencies source
}  