Added warning when using restricted names in Windows.

src/cargo/ops/cargo_package.rs

@@ -823,25 +823,12 @@ fn check_filename(file: &Path, shell: &mut Shell) -> CargoResult<()> {
             file.display()
         )
     }
-    let mut check_windows = |name| -> CargoResult<()> {
-        if restricted_names::is_windows_reserved(name) {
-            shell.warn(format!(
-                "file {} is a reserved Windows filename, \
+    if restricted_names::is_windows_reserved_path(file) {
+        shell.warn(format!(
+            "file {} is a reserved Windows filename, \
                 it will not work on Windows platforms",
-                file.display()
-            ))?;
-        }
-        Ok(())
-    };
-    for component in file.iter() {
-        if let Some(component) = component.to_str() {
-            check_windows(component)?;
-        }
-    }
-    if file.extension().is_some() {
-        if let Some(stem) = file.file_stem().and_then(|s| s.to_str()) {
-            check_windows(stem)?;
-        }
+            file.display()
+        ))?;
     }
     Ok(())
 }

src/cargo/sources/registry/mod.rs

@@ -178,7 +178,7 @@ use crate::sources::PathSource;
 use crate::util::errors::CargoResultExt;
 use crate::util::hex;
 use crate::util::into_url::IntoUrl;
-use crate::util::{CargoResult, Config, Filesystem};
+use crate::util::{restricted_names, CargoResult, Config, Filesystem};
 
 const PACKAGE_SOURCE_LOCK: &str = ".cargo-ok";
 pub const CRATES_IO_INDEX: &str = "https://github.com/rust-lang/crates.io-index";
@@ -495,11 +495,18 @@ impl<'cfg> RegistrySource<'cfg> {
                     prefix
                 )
             }
-
-            // Once that's verified, unpack the entry as usual.
-            entry
-                .unpack_in(parent)
-                .chain_err(|| format!("failed to unpack entry at `{}`", entry_path.display()))?;
+            // Unpacking failed
+            let mut result = entry.unpack_in(parent).map_err(anyhow::Error::from);
+            if cfg!(windows) && restricted_names::is_windows_reserved_path(&entry_path) {
+                result = result.chain_err(|| {
+                    format!(
+                        "`{}` appears to contain a reserved Windows path, \
+                        it cannot be extracted on Windows",
+                        entry_path.display()
+                    )
+                });
+            }
+            result.chain_err(|| format!("failed to unpack entry at `{}`", entry_path.display()))?;
         }
 
         // Write to the lock file to indicate that unpacking was successful.

src/cargo/util/restricted_names.rs

@@ -2,6 +2,7 @@
 
 use crate::util::CargoResult;
 use anyhow::bail;
+use std::path::Path;
 
 /// Returns `true` if the name contains non-ASCII characters.
 pub fn is_non_ascii_name(name: &str) -> bool {
@@ -81,3 +82,13 @@ pub fn validate_package_name(name: &str, what: &str, help: &str) -> CargoResult<
     }
     Ok(())
 }
+
+// Check the entire path for names reserved in Windows.
+pub fn is_windows_reserved_path(path: &Path) -> bool {
+    path.iter()
+        .filter_map(|component| component.to_str())
+        .any(|component| {
+            let stem = component.split('.').next().unwrap();
+            is_windows_reserved(stem)
+        })
+}

tests/testsuite/package.rs

@@ -1744,3 +1744,55 @@ src/lib.rs
         )
         .run();
 }
+
+#[cargo_test]
+#[cfg(windows)]
+fn reserved_windows_name() {
+    Package::new("bar", "1.0.0")
+        .file("src/lib.rs", "pub mod aux;")
+        .file("src/aux.rs", "")
+        .publish();
+
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+            [project]
+            name = "foo"
+            version = "0.0.1"
+            authors = []
+            license = "MIT"
+            description = "foo"
+
+            [dependencies]
+            bar = "1.0.0"
+        "#,
+        )
+        .file("src/main.rs", "extern crate bar;\nfn main() {  }")
+        .build();
+    p.cargo("package")
+        .with_status(101)
+        .with_stderr_contains(
+            "\
+error: failed to verify package tarball
+
+Caused by:
+  failed to download replaced source registry `[..]`
+
+Caused by:
+  failed to unpack package `[..] `[..]`)`
+
+Caused by:
+  failed to unpack entry at `[..]aux.rs`
+
+Caused by:
+  `[..]aux.rs` appears to contain a reserved Windows path, it cannot be extracted on Windows
+
+Caused by:
+  failed to unpack `[..]aux.rs`
+
+Caused by:
+  failed to unpack `[..]aux.rs` into `[..]aux.rs`",
+        )
+        .run();
+}