Change scraping to apply to all workspace packages instead of just

root units. Only attach Docscrape unit dependencies to workspace Doc
units. Add test for scraping examples with complex reverse dependencies.

src/cargo/core/compiler/compilation.rs

@@ -188,11 +188,7 @@ impl<'cfg> Compilation<'cfg> {
         unit: &Unit,
         script_meta: Option<Metadata>,
     ) -> CargoResult<ProcessBuilder> {
-        let mut rustdoc = ProcessBuilder::new(&*self.config.rustdoc()?);
-        if self.config.extra_verbose() {
-            rustdoc.display_env_vars();
-        }
-
+        let rustdoc = ProcessBuilder::new(&*self.config.rustdoc()?);
         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/mod.rs

@@ -21,7 +21,6 @@ mod unit;
 pub mod unit_dependencies;
 pub mod unit_graph;
 
-use std::collections::HashSet;
 use std::env;
 use std::ffi::{OsStr, OsString};
 use std::fs::{self, File};
@@ -665,18 +664,14 @@ fn rustdoc(cx: &mut Context<'_, '_>, unit: &Unit) -> CargoResult<Work> {
             .arg("--scrape-examples-output-path")
             .arg(scrape_output_path(unit)?);
 
-        // Limit the scraped examples to just crates in the root set
-        let root_packages = cx
-            .bcx
-            .roots
-            .iter()
-            .map(|root| root.pkg.name())
-            .collect::<HashSet<_>>();
-        for pkg in root_packages {
-            rustdoc.arg("--scrape-examples-target-crate").arg(pkg);
+        // Only scrape example for items from crates in the workspace, to reduce generated file size
+        for pkg in cx.bcx.ws.members() {
+            rustdoc
+                .arg("--scrape-examples-target-crate")
+                .arg(pkg.name());
         }
-    } else if cx.bcx.scrape_units.len() > 0 && cx.bcx.roots.contains(unit) {
-        // We only pass scraped examples to packages in the workspace (bcx.roots)
+    } else if cx.bcx.scrape_units.len() > 0 && cx.bcx.ws.is_member(&unit.pkg) {
+        // We only pass scraped examples to packages in the workspace
         // since examples are only coming from reverse-dependencies of workspace packages
 
         rustdoc.arg("-Zunstable-options");

src/cargo/core/compiler/unit_dependencies.rs

@@ -473,19 +473,21 @@ 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() {
-        // 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,
-            scrape_unit,
-            &scrape_unit.pkg,
-            &scrape_unit.target,
-            unit_for,
-            scrape_unit.kind,
-            scrape_unit.mode,
-        )?);
+    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());
+            deps_of(scrape_unit, state, unit_for)?;
+            ret.push(new_unit_dep(
+                state,
+                scrape_unit,
+                &scrape_unit.pkg,
+                &scrape_unit.target,
+                unit_for,
+                scrape_unit.kind,
+                scrape_unit.mode,
+            )?);
+        }
     }
 
     Ok(ret)

tests/testsuite/doc.rs

@@ -2235,3 +2235,66 @@ fn scrape_examples_avoid_build_script_cycle() {
         .masquerade_as_nightly_cargo()
         .run();
 }
+
+
+#[cargo_test]
+fn scrape_examples_complex_reverse_dependencies() {
+    if !is_nightly() {
+        // --scrape-examples is unstable
+        return;
+    }
+
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name = "foo"
+                version = "0.0.1"
+                authors = []
+
+                [dev-dependencies]
+                a = {path = "a", features = ["feature"]}
+                b = {path = "b"}
+
+                [workspace]
+                members = ["b"]
+            "#,
+        )
+        .file("src/lib.rs", "")
+        .file("examples/ex.rs", "fn main() { a::f(); }")
+        .file(
+            "a/Cargo.toml",
+            r#"
+                [package]
+                name = "a"
+                version = "0.0.1"
+                authors = []
+
+                [lib]
+                proc-macro = true
+
+                [dependencies]
+                b = {path = "../b"}
+
+                [features]
+                feature = []
+            "#,
+        )
+        .file("a/src/lib.rs",  "#[cfg(feature)] pub fn f();")
+        .file(
+            "b/Cargo.toml",
+            r#"
+                [package]
+                name = "b"
+                version = "0.0.1"
+                authors = []
+            "#,
+        )
+        .file("b/src/lib.rs", "")
+        .build();
+
+    p.cargo("doc -Zunstable-options --scrape-examples all")
+        .masquerade_as_nightly_cargo()
+        .run();
+}