build: allow deno_runtime crate to build in docs.rs (#11602)

Cargo.lock

@@ -818,7 +818,7 @@ dependencies = [
 
 [[package]]
 name = "deno_runtime"
-version = "0.22.0"
+version = "0.22.2"
 dependencies = [
  "atty",
  "deno_broadcast_channel",

runtime/Cargo.toml

@@ -2,13 +2,17 @@
 
 [package]
 name = "deno_runtime"
-version = "0.22.0"
+version = "0.22.2"
 authors = ["the Deno authors"]
 edition = "2018"
 license = "MIT"
 repository = "https://github.com/denoland/deno"
 description = "Provides the deno runtime library"
 
+[features]
+# "fake" feature that allows to generate docs on docs.rs
+docsrs = []
+
 [lib]
 name = "deno_runtime"
 path = "lib.rs"
@@ -88,3 +92,6 @@ nix = "0.20.0"
 [dev-dependencies]
 # Used in benchmark
 test_util = { path = "../test_util" }
+
+[package.metadata.docs.rs]
+features = ["docsrs"]

runtime/build.rs

@@ -1,19 +1,24 @@
 // Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
 
-use deno_core::Extension;
-use deno_core::JsRuntime;
-use deno_core::RuntimeOptions;
 use std::env;
 use std::path::Path;
 use std::path::PathBuf;
 
-// TODO(bartlomieju): this module contains a lot of duplicated
+// This is a shim that allows to generate documentation on docs.rs
-// logic with `cli/build.rs`, factor out to `deno_core`.
+#[cfg(not(feature = "docsrs"))]
-fn create_snapshot(
+mod not_docs {
+  use super::*;
+  use deno_core::Extension;
+  use deno_core::JsRuntime;
+  use deno_core::RuntimeOptions;
+
+  // TODO(bartlomieju): this module contains a lot of duplicated
+  // logic with `cli/build.rs`, factor out to `deno_core`.
+  fn create_snapshot(
     mut js_runtime: JsRuntime,
     snapshot_path: &Path,
     files: Vec<PathBuf>,
-) {
+  ) {
     // TODO(nayeemrmn): https://github.com/rust-lang/cargo/issues/3946 to get the
     // workspace root.
     let display_root = Path::new(env!("CARGO_MANIFEST_DIR")).parent().unwrap();
@@ -34,9 +39,9 @@ fn create_snapshot(
     println!("Snapshot size: {}", snapshot_slice.len());
     std::fs::write(&snapshot_path, snapshot_slice).unwrap();
     println!("Snapshot written to: {} ", snapshot_path.display());
-}
+  }
 
-fn create_runtime_snapshot(snapshot_path: &Path, files: Vec<PathBuf>) {
+  fn create_runtime_snapshot(snapshot_path: &Path, files: Vec<PathBuf>) {
     let extensions: Vec<Extension> = vec![
       deno_webidl::init(),
       deno_console::init(),
@@ -77,29 +82,9 @@ fn create_runtime_snapshot(snapshot_path: &Path, files: Vec<PathBuf>) {
       ..Default::default()
     });
     create_snapshot(js_runtime, snapshot_path, files);
-}
-
-fn main() {
-  // Skip building from docs.rs.
-  if env::var_os("DOCS_RS").is_some() {
-    return;
   }
 
-  // To debug snapshot issues uncomment:
+  fn get_js_files(d: &str) -> Vec<PathBuf> {
-  // op_fetch_asset::trace_serializer();
-
-  println!("cargo:rustc-env=TARGET={}", env::var("TARGET").unwrap());
-  println!("cargo:rustc-env=PROFILE={}", env::var("PROFILE").unwrap());
-  let o = PathBuf::from(env::var_os("OUT_DIR").unwrap());
-
-  // Main snapshot
-  let runtime_snapshot_path = o.join("CLI_SNAPSHOT.bin");
-
-  let js_files = get_js_files("js");
-  create_runtime_snapshot(&runtime_snapshot_path, js_files);
-}
-
-fn get_js_files(d: &str) -> Vec<PathBuf> {
     let manifest_dir = Path::new(env!("CARGO_MANIFEST_DIR"));
     let mut js_files = std::fs::read_dir(d)
       .unwrap()
@@ -111,4 +96,34 @@ fn get_js_files(d: &str) -> Vec<PathBuf> {
       .collect::<Vec<PathBuf>>();
     js_files.sort();
     js_files
+  }
+
+  pub fn build_snapshot(runtime_snapshot_path: PathBuf) {
+    let js_files = get_js_files("js");
+    create_runtime_snapshot(&runtime_snapshot_path, js_files);
+  }
+}
+
+fn main() {
+  // To debug snapshot issues uncomment:
+  // op_fetch_asset::trace_serializer();
+
+  println!("cargo:rustc-env=TARGET={}", env::var("TARGET").unwrap());
+  println!("cargo:rustc-env=PROFILE={}", env::var("PROFILE").unwrap());
+  let o = PathBuf::from(env::var_os("OUT_DIR").unwrap());
+
+  // Main snapshot
+  let runtime_snapshot_path = o.join("CLI_SNAPSHOT.bin");
+
+  // If we're building on docs.rs we just create
+  // and empty snapshot file and return, because `rusty_v8`
+  // doesn't actually compile on docs.rs
+  if env::var_os("DOCS_RS").is_some() {
+    let snapshot_slice = &[];
+    std::fs::write(&runtime_snapshot_path, snapshot_slice).unwrap();
+    return;
+  }
+
+  #[cfg(not(feature = "docsrs"))]
+  not_docs::build_snapshot(runtime_snapshot_path)
 }