Fix several bugs when checking wasmtime repo:

* Docscrape unit not having dev-dependencies included
* Sources for reverse-dependencies generated to the wrong directory
* Incorrect features being selected for Docscrape units
* Panics from Docscrape-dependent packages not being available

src/cargo/core/compiler/compilation.rs

@@ -188,7 +188,11 @@ impl<'cfg> Compilation<'cfg> {
         unit: &Unit,
         script_meta: Option<Metadata>,
     ) -> CargoResult<ProcessBuilder> {
-        let rustdoc = ProcessBuilder::new(&*self.config.rustdoc()?);
+        let mut rustdoc = ProcessBuilder::new(&*self.config.rustdoc()?);
+        if self.config.extra_verbose() {
+            rustdoc.display_env_vars();
+        }
+
         let cmd = fill_rustc_tool_env(rustdoc, unit);
         let mut p = self.fill_env(cmd, &unit.pkg, script_meta, unit.kind, true)?;
         unit.target.edition().cmd_edition_arg(&mut p);

src/cargo/core/compiler/context/compilation_files.rs

@@ -191,7 +191,7 @@ impl<'a, 'cfg: 'a> CompilationFiles<'a, 'cfg> {
     /// Returns the directory where the artifacts for the given unit are
     /// initially created.
     pub fn out_dir(&self, unit: &Unit) -> PathBuf {
-        if unit.mode.is_doc() {
+        if unit.mode.is_doc() || unit.mode.is_doc_scrape() {
             self.layout(unit.kind).doc().to_path_buf()
         } else if unit.mode.is_doc_test() {
             panic!("doc tests do not have an out dir");
@@ -418,9 +418,15 @@ impl<'a, 'cfg: 'a> CompilationFiles<'a, 'cfg> {
                 vec![]
             }
             CompileMode::Docscrape => {
-                // Docscrape only generates temporary *.examples files to pass to rustdoc
-                // so they're not important to track
-                vec![]
+                let path = self
+                    .deps_dir(unit)
+                    .join(format!("{}.examples", unit.buildkey()));
+                vec![OutputFile {
+                    path,
+                    hardlink: None,
+                    export_path: None,
+                    flavor: FileFlavor::Normal,
+                }]
             }
             CompileMode::Test
             | CompileMode::Build

src/cargo/core/compiler/mod.rs

@@ -652,12 +652,13 @@ fn rustdoc(cx: &mut Context<'_, '_>, unit: &Unit) -> CargoResult<Work> {
     rustdoc.arg("-C").arg(format!("metadata={}", metadata));
 
     let scrape_output_path = |unit: &Unit| -> CargoResult<PathBuf> {
-        let layout = cx.files().layout(unit.kind);
-        let output_dir = layout.prepare_tmp()?;
+        let output_dir = cx.files().deps_dir(unit);
         Ok(output_dir.join(format!("{}.examples", unit.buildkey())))
     };
 
     if unit.mode.is_doc_scrape() {
+        debug_assert!(cx.bcx.scrape_units.contains(unit));
+
         rustdoc.arg("-Zunstable-options");
 
         rustdoc

src/cargo/core/compiler/unit_dependencies.rs

@@ -256,6 +256,7 @@ fn compute_deps(
         if !dep.is_transitive()
             && !unit.target.is_test()
             && !unit.target.is_example()
+            && !unit.mode.is_doc_scrape()
             && !unit.mode.is_any_test()
         {
             return false;
@@ -473,7 +474,8 @@ fn compute_deps_doc(
 
     // Add all units being scraped for examples as a dependency of Doc units.
     for scrape_unit in state.scrape_units.iter() {
-        let unit_for = UnitFor::new_normal();
+        // This needs to match the FeaturesFor used in cargo_compile::generate_targets.
+        let unit_for = UnitFor::new_host(scrape_unit.target.proc_macro());
         deps_of(scrape_unit, state, unit_for)?;
         ret.push(new_unit_dep(
             state,

src/cargo/ops/cargo_compile.rs

@@ -368,18 +368,27 @@ pub fn create_bcx<'a, 'cfg>(
 
     let target_data = RustcTargetData::new(ws, &build_config.requested_kinds)?;
 
-    let specs = spec.to_package_id_specs(ws)?;
-    let has_dev_units = if filter.need_dev_deps(build_config.mode) {
-        HasDevUnits::Yes
+    let all_packages = &Packages::All;
+    let full_specs = if rustdoc_scrape_examples.is_some() {
+        all_packages
     } else {
-        HasDevUnits::No
+        spec
     };
+
+    let specs = spec.to_package_id_specs(ws)?;
+    let resolve_specs = full_specs.to_package_id_specs(ws)?;
+    let has_dev_units =
+        if filter.need_dev_deps(build_config.mode) || rustdoc_scrape_examples.is_some() {
+            HasDevUnits::Yes
+        } else {
+            HasDevUnits::No
+        };
     let resolve = ops::resolve_ws_with_opts(
         ws,
         &target_data,
         &build_config.requested_kinds,
         cli_features,
-        &specs,
+        &resolve_specs,
         has_dev_units,
         crate::core::resolver::features::ForceAllTargets::No,
     )?;
@@ -494,8 +503,7 @@ pub fn create_bcx<'a, 'cfg>(
 
     let mut scrape_units = match rustdoc_scrape_examples {
         Some(scrape_filter) => {
-            let specs = Packages::All.to_package_id_specs(ws)?;
-            let to_build_ids = resolve.specs_to_ids(&specs)?;
+            let to_build_ids = resolve.specs_to_ids(&resolve_specs)?;
             let to_builds = pkg_set.get_many(to_build_ids)?;
             let mode = CompileMode::Docscrape;
 

tests/testsuite/doc.rs

@@ -2184,6 +2184,9 @@ fn scrape_examples_basic() {
     let doc_html = p.read_file("target/doc/foo/fn.foo.html");
     assert!(doc_html.contains("Examples found in repository"));
     assert!(doc_html.contains("More examples"));
+
+    // Ensure that the reverse-dependency has its sources generated
+    assert!(p.build_dir().join("doc/src/ex/ex.rs.html").exists());
 }
 
 #[cargo_test]