Do not supply --crate-version flag to rustdoc if present in RUSTDOCFLAGS

src/cargo/core/compiler/mod.rs

@@ -49,6 +49,8 @@ use crate::util::machine_message::Message;
 use crate::util::{self, machine_message, ProcessBuilder};
 use crate::util::{internal, join_paths, paths, profile};
 
+const RUSTDOC_CRATE_VERSION_FLAG: &str = "--crate-version";
+
 /// A glorified callback for executing calls to rustc. Rather than calling rustc
 /// directly, we'll use an `Executor`, giving clients an opportunity to intercept
 /// the build calls.
@@ -562,7 +564,6 @@ fn rustdoc<'a, 'cfg>(cx: &mut Context<'a, 'cfg>, unit: &Unit<'a>) -> CargoResult
     let mut rustdoc = cx.compilation.rustdoc_process(unit.pkg, unit.target)?;
     rustdoc.inherit_jobserver(&cx.jobserver);
     rustdoc.arg("--crate-name").arg(&unit.target.crate_name());
-    add_crate_versions_if_requested(bcx, unit, &mut rustdoc);
     add_path_args(bcx, unit, &mut rustdoc);
     add_cap_lints(bcx, unit, &mut rustdoc);
 
@@ -593,6 +594,8 @@ fn rustdoc<'a, 'cfg>(cx: &mut Context<'a, 'cfg>, unit: &Unit<'a>) -> CargoResult
 
     rustdoc.args(bcx.rustdocflags_args(unit));
 
+    add_crate_versions_if_requested(bcx, unit, &mut rustdoc);
+
     let name = unit.pkg.name().to_string();
     let build_script_outputs = Arc::clone(&cx.build_script_outputs);
     let package_id = unit.pkg.package_id();
@@ -629,19 +632,31 @@ fn rustdoc<'a, 'cfg>(cx: &mut Context<'a, 'cfg>, unit: &Unit<'a>) -> CargoResult
     }))
 }
 
-fn add_crate_versions_if_requested(
-    bcx: &BuildContext<'_, '_>,
-    unit: &Unit<'_>,
+fn add_crate_versions_if_requested<'a>(
+    bcx: &BuildContext<'a, '_>,
+    unit: &Unit<'a>,
     rustdoc: &mut ProcessBuilder,
 ) {
-    if !bcx.config.cli_unstable().crate_versions {
-        return;
+    if bcx.config.cli_unstable().crate_versions && !crate_version_flag_already_present(rustdoc) {
+        append_crate_version_flag(unit, rustdoc);
     }
+}
+
+// The --crate-version flag could have already been passed in RUSTDOCFLAGS
+// or as an extra compiler argument for rustdoc
+fn crate_version_flag_already_present(rustdoc: &ProcessBuilder) -> bool {
+    rustdoc.get_args().iter().any(|flag| {
+        flag.to_str()
+            .map_or(false, |flag| flag.starts_with(RUSTDOC_CRATE_VERSION_FLAG))
+    })
+}
+
+fn append_crate_version_flag(unit: &Unit<'_>, rustdoc: &mut ProcessBuilder) {
     rustdoc
         .arg("-Z")
         .arg("unstable-options")
-        .arg("--crate-version")
-        .arg(&unit.pkg.version().to_string());
+        .arg(RUSTDOC_CRATE_VERSION_FLAG)
+        .arg(unit.pkg.version().to_string());
 }
 
 // The path that we pass to rustc is actually fairly important because it will

tests/testsuite/doc.rs

@@ -1534,12 +1534,50 @@ fn crate_versions() {
         .masquerade_as_nightly_cargo()
         .run();
 
-    let doc_file = p.root().join("target/doc/foo/index.html");
-    let mut doc_html = String::new();
-    File::open(&doc_file)
-        .unwrap()
-        .read_to_string(&mut doc_html)
-        .unwrap();
+    let output_path = p.root().join("target/doc/foo/index.html");
+    let output_documentation = fs::read_to_string(&output_path).unwrap();
+
+    assert!(output_documentation.contains("Version 1.2.4"));
+}
+
+#[cargo_test]
+fn crate_versions_flag_is_overridden() {
+    // Testing unstable flag
+    if !is_nightly() {
+        return;
+    }
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+            [package]
+            name = "foo"
+            version = "1.2.4"
+            authors = []
+        "#,
+        )
+        .file("src/lib.rs", "")
+        .build();
 
-    assert!(doc_html.contains("Version 1.2.4"));
+    let output_documentation = || {
+        let output_path = p.root().join("target/doc/foo/index.html");
+        fs::read_to_string(&output_path).unwrap()
+    };
+    let asserts = |html: String| {
+        assert!(!html.contains("1.2.4"));
+        assert!(html.contains("Version 2.0.3"));
+    };
+
+    p.cargo("-Z crate-versions doc")
+        .masquerade_as_nightly_cargo()
+        .env("RUSTDOCFLAGS", "-Z unstable-options --crate-version 2.0.3")
+        .run();
+    asserts(output_documentation());
+
+    p.build_dir().rm_rf();
+
+    p.cargo("-Z crate-versions rustdoc -- -Z unstable-options --crate-version 2.0.3")
+        .masquerade_as_nightly_cargo()
+        .run();
+    asserts(output_documentation());
 }