Auto merge of #10533 - willcrichton:fix-scrape-profile, r=epage

Fix how scrape-examples handles proc macros

### What does this PR try to resolve?

This PR fixes #10500.

Previously, the scrape-examples extension did some shenanigans in `build_unit_dependencies` in order to scrape `proc-macro` crates. But this code is useless since `proc-macro` crates cannot export functions, so we avoid this issue entirely by filtering proc-macro targets.

### How should we test and review this PR?

I added the test `scrape_examples_configure_profile` to ensure that the issue in #10500 is fixed.

r? `@ehuss`

src/cargo/core/compiler/unit_dependencies.rs

@@ -711,11 +711,6 @@ fn compute_deps_doc(
     // Add all units being scraped for examples as a dependency of Doc units.
     if state.ws.is_member(&unit.pkg) {
         for scrape_unit in state.scrape_units.iter() {
-            // This needs to match the FeaturesFor used in cargo_compile::generate_targets.
-            let unit_for = UnitFor::new_host(
-                scrape_unit.target.proc_macro(),
-                unit_for.root_compile_kind(),
-            );
             deps_of(scrape_unit, state, unit_for)?;
             ret.push(new_unit_dep(
                 state,

src/cargo/ops/cargo_compile.rs

@@ -546,6 +546,10 @@ pub fn create_bcx<'a, 'cfg>(
                 &profiles,
                 interner,
             )?
+            .into_iter()
+            // Proc macros should not be scraped for functions, since they only export macros
+            .filter(|unit| !unit.target.proc_macro())
+            .collect::<Vec<_>>()
         }
         None => Vec::new(),
     };

tests/testsuite/doc.rs

@@ -2560,6 +2560,39 @@ fn scrape_examples_missing_flag() {
         .run();
 }
 
+#[cargo_test]
+fn scrape_examples_configure_profile() {
+    if !is_nightly() {
+        // -Z rustdoc-scrape-examples is unstable
+        return;
+    }
+
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name = "foo"
+                version = "0.0.1"
+                authors = []
+
+                [profile.dev]
+                panic = "abort"
+            "#,
+        )
+        .file("examples/ex.rs", "fn main() { foo::foo(); }")
+        .file("src/lib.rs", "pub fn foo() {}\npub fn bar() { foo(); }")
+        .build();
+
+    p.cargo("doc -Zunstable-options -Z rustdoc-scrape-examples=all")
+        .masquerade_as_nightly_cargo()
+        .run();
+
+    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"));
+}
+
 #[cargo_test]
 fn lib_before_bin() {
     // Checks that the library is documented before the binary.