Auto merge of #38589 - aidanhs:aphs-stage0-rustdoc-test, r=alexcrichton

Teach `rustdoc --test` about `--sysroot`, pass it when testing rust

This permits rustdoc tests to work in stage0.

Logical continuation of #36586.

Snippet from https://github.com/rust-lang/rust/issues/38575#issuecomment-269090724:

> it should actually be possible to run all the libstd tests immediately after creating std of stage0-out - there's no reason to build librustc at all if you've just made a change to (for example) libcollections, `./x.py test src/libcollections --stage 0 -v --incremental` should just work

This PR makes it so (or appears to in my testing).

r? @alexcrichton

src/bootstrap/bin/rustc.rs

@@ -67,6 +67,7 @@ fn main() {
         ("RUSTC_REAL", "RUSTC_LIBDIR")
     };
     let stage = env::var("RUSTC_STAGE").expect("RUSTC_STAGE was not set");
+    let sysroot = env::var_os("RUSTC_SYSROOT").expect("RUSTC_SYSROOT was not set");
 
     let rustc = env::var_os(rustc).unwrap_or_else(|| panic!("{:?} was not set", rustc));
     let libdir = env::var_os(libdir).unwrap_or_else(|| panic!("{:?} was not set", libdir));
@@ -83,7 +84,7 @@ fn main() {
     if let Some(target) = target {
         // The stage0 compiler has a special sysroot distinct from what we
         // actually downloaded, so we just always pass the `--sysroot` option.
-        cmd.arg("--sysroot").arg(env::var_os("RUSTC_SYSROOT").expect("RUSTC_SYSROOT was not set"));
+        cmd.arg("--sysroot").arg(sysroot);
 
         // When we build Rust dylibs they're all intended for intermediate
         // usage, so make sure we pass the -Cprefer-dynamic flag instead of

src/bootstrap/bin/rustdoc.rs

@@ -25,6 +25,7 @@ fn main() {
     let rustdoc = env::var_os("RUSTDOC_REAL").expect("RUSTDOC_REAL was not set");
     let libdir = env::var_os("RUSTC_LIBDIR").expect("RUSTC_LIBDIR was not set");
     let stage = env::var("RUSTC_STAGE").expect("RUSTC_STAGE was not set");
+    let sysroot = env::var_os("RUSTC_SYSROOT").expect("RUSTC_SYSROOT was not set");
 
     let mut dylib_path = bootstrap::util::dylib_path();
     dylib_path.insert(0, PathBuf::from(libdir));
@@ -35,6 +36,8 @@ fn main() {
         .arg(format!("stage{}", stage))
         .arg("--cfg")
         .arg("dox")
+        .arg("--sysroot")
+        .arg(sysroot)
         .env(bootstrap::util::dylib_path_var(),
              env::join_paths(&dylib_path).unwrap());
     std::process::exit(match cmd.status() {

src/librustdoc/lib.rs

@@ -267,13 +267,14 @@ pub fn main_args(args: &[String]) -> isize {
     };
     let crate_name = matches.opt_str("crate-name");
     let playground_url = matches.opt_str("playground-url");
+    let maybe_sysroot = matches.opt_str("sysroot").map(PathBuf::from);
 
     match (should_test, markdown_input) {
         (true, true) => {
-            return markdown::test(input, cfgs, libs, externs, test_args)
+            return markdown::test(input, cfgs, libs, externs, test_args, maybe_sysroot)
         }
         (true, false) => {
-            return test::run(input, cfgs, libs, externs, test_args, crate_name)
+            return test::run(input, cfgs, libs, externs, test_args, crate_name, maybe_sysroot)
         }
         (false, true) => return markdown::render(input,
                                                  output.unwrap_or(PathBuf::from("doc")),

src/librustdoc/markdown.rs

@@ -144,7 +144,7 @@ pub fn render(input: &str, mut output: PathBuf, matches: &getopts::Matches,
 
 /// Run any tests/code examples in the markdown file `input`.
 pub fn test(input: &str, cfgs: Vec<String>, libs: SearchPaths, externs: Externs,
-            mut test_args: Vec<String>) -> isize {
+            mut test_args: Vec<String>, maybe_sysroot: Option<PathBuf>) -> isize {
     let input_str = match load_string(input) {
         Ok(s) => s,
         Err(LoadStringError::ReadFail) => return 1,
@@ -154,7 +154,7 @@ pub fn test(input: &str, cfgs: Vec<String>, libs: SearchPaths, externs: Externs,
     let mut opts = TestOptions::default();
     opts.no_crate_inject = true;
     let mut collector = Collector::new(input.to_string(), cfgs, libs, externs,
-                                       true, opts);
+                                       true, opts, maybe_sysroot);
     find_testable_code(&input_str, &mut collector);
     test_args.insert(0, "rustdoctest".to_string());
     testing::test_main(&test_args, collector.tests);

src/librustdoc/test.rs

@@ -54,14 +54,15 @@ pub fn run(input: &str,
            libs: SearchPaths,
            externs: Externs,
            mut test_args: Vec<String>,
-           crate_name: Option<String>)
+           crate_name: Option<String>,
+           maybe_sysroot: Option<PathBuf>)
            -> isize {
     let input_path = PathBuf::from(input);
     let input = config::Input::File(input_path.clone());
 
     let sessopts = config::Options {
-        maybe_sysroot: Some(env::current_exe().unwrap().parent().unwrap()
-                                              .parent().unwrap().to_path_buf()),
+        maybe_sysroot: maybe_sysroot.clone().or_else(
+            || Some(env::current_exe().unwrap().parent().unwrap().parent().unwrap().to_path_buf())),
         search_paths: libs.clone(),
         crate_types: vec![config::CrateTypeDylib],
         externs: externs.clone(),
@@ -99,7 +100,8 @@ pub fn run(input: &str,
                                        libs,
                                        externs,
                                        false,
-                                       opts);
+                                       opts,
+                                       maybe_sysroot);
 
     {
         let dep_graph = DepGraph::new(false);
@@ -157,7 +159,8 @@ fn scrape_test_config(krate: &::rustc::hir::Crate) -> TestOptions {
 fn runtest(test: &str, cratename: &str, cfgs: Vec<String>, libs: SearchPaths,
            externs: Externs,
            should_panic: bool, no_run: bool, as_test_harness: bool,
-           compile_fail: bool, mut error_codes: Vec<String>, opts: &TestOptions) {
+           compile_fail: bool, mut error_codes: Vec<String>, opts: &TestOptions,
+           maybe_sysroot: Option<PathBuf>) {
     // the test harness wants its own `main` & top level functions, so
     // never wrap the test in `fn main() { ... }`
     let test = maketest(test, Some(cratename), as_test_harness, opts);
@@ -168,8 +171,8 @@ fn runtest(test: &str, cratename: &str, cfgs: Vec<String>, libs: SearchPaths,
     let outputs = OutputTypes::new(&[(OutputType::Exe, None)]);
 
     let sessopts = config::Options {
-        maybe_sysroot: Some(env::current_exe().unwrap().parent().unwrap()
-                                              .parent().unwrap().to_path_buf()),
+        maybe_sysroot: maybe_sysroot.or_else(
+            || Some(env::current_exe().unwrap().parent().unwrap().parent().unwrap().to_path_buf())),
         search_paths: libs,
         crate_types: vec![config::CrateTypeExecutable],
         output_types: outputs,
@@ -379,11 +382,12 @@ pub struct Collector {
     current_header: Option<String>,
     cratename: String,
     opts: TestOptions,
+    maybe_sysroot: Option<PathBuf>,
 }
 
 impl Collector {
     pub fn new(cratename: String, cfgs: Vec<String>, libs: SearchPaths, externs: Externs,
-               use_headers: bool, opts: TestOptions) -> Collector {
+               use_headers: bool, opts: TestOptions, maybe_sysroot: Option<PathBuf>) -> Collector {
         Collector {
             tests: Vec::new(),
             names: Vec::new(),
@@ -395,6 +399,7 @@ impl Collector {
             current_header: None,
             cratename: cratename,
             opts: opts,
+            maybe_sysroot: maybe_sysroot,
         }
     }
 
@@ -413,6 +418,7 @@ impl Collector {
         let externs = self.externs.clone();
         let cratename = self.cratename.to_string();
         let opts = self.opts.clone();
+        let maybe_sysroot = self.maybe_sysroot.clone();
         debug!("Creating test {}: {}", name, test);
         self.tests.push(testing::TestDescAndFn {
             desc: testing::TestDesc {
@@ -432,7 +438,8 @@ impl Collector {
                         as_test_harness,
                         compile_fail,
                         error_codes,
-                        &opts);
+                        &opts,
+                        maybe_sysroot);
             })
         });
     }