test(package): show corner cases of vcs dirtiness check

This is a test showing corner cases that dirty files outside
the package being packaging actually made the `.crate` file dirty.
However, `cargo package` and `.cargo_vcs_info.json` didn't capture it.

Author: weihanglo

tests/testsuite/package.rs

@@ -1156,6 +1156,125 @@ src/lib.rs
         .run();
 }
 
+#[cargo_test]
+fn dirty_file_outside_pkg_root_considered_dirty() {
+    if !symlink_supported() {
+        return;
+    }
+    let (p, repo) = git::new_repo("foo", |p| {
+        p.file(
+            "Cargo.toml",
+            r#"
+                [workspace]
+                members = ["isengard"]
+                resolver = "2"
+                [workspace.package]
+                edition = "2015"
+            "#,
+        )
+        .file("LICENSE", "before")
+        .file("README.md", "before")
+        .file(
+            "isengard/Cargo.toml",
+            r#"
+                [package]
+                name = "isengard"
+                edition.workspace = true
+                homepage = "saruman"
+                description = "saruman"
+                license-file = "../LICENSE"
+            "#,
+        )
+        .file("isengard/src/lib.rs", "")
+        .symlink("README.md", "isengard/README.md")
+    });
+    git::commit(&repo);
+
+    // Change files outside pkg root should be treated as dirty.
+    // The next `cargo package` is expected to fail.
+    //
+    // * relative path outside pkg root of package.{license-file,readme}
+    //   should be considered dirty
+    p.change_file("LICENSE", "after");
+    // * symlink to outside pkg root of package.{license-file,readme}
+    //   should be considered dirty
+    p.change_file("README.md", "after");
+    // * when workspace inheritance is involved and changed,
+    // pkg should be considered dirty
+    p.change_file(
+        "Cargo.toml",
+        r#"
+            [workspace]
+            members = ["isengard"]
+            resolver = "2"
+
+            [workspace.package]
+            edition = "2021"
+        "#,
+    );
+
+    // Ensure dirty files be reported.
+    p.cargo("package --workspace --no-verify")
+        .with_stderr_data(str![[r#"
+[PACKAGING] isengard v0.0.0 ([ROOT]/foo/isengard)
+[PACKAGED] 7 files, [FILE_SIZE]B ([FILE_SIZE]B compressed)
+
+"#]])
+        .run();
+
+    let cargo_toml = str![[r##"
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies.
+#
+# If you are reading this file be aware that the original Cargo.toml
+# will likely look very different (and much more reasonable).
+# See Cargo.toml.orig for the original contents.
+
+[package]
+edition = "2021"
+name = "isengard"
+build = false
+autolib = false
+autobins = false
+autoexamples = false
+autotests = false
+autobenches = false
+description = "saruman"
+homepage = "saruman"
+readme = "README.md"
+license-file = "LICENSE"
+
+[lib]
+name = "isengard"
+path = "src/lib.rs"
+
+"##]];
+
+    let f = File::open(&p.root().join("target/package/isengard-0.0.0.crate")).unwrap();
+    validate_crate_contents(
+        f,
+        "isengard-0.0.0.crate",
+        &[
+            ".cargo_vcs_info.json",
+            "Cargo.toml",
+            "Cargo.toml.orig",
+            "src/lib.rs",
+            "Cargo.lock",
+            "LICENSE",
+            "README.md",
+        ],
+        [
+            ("README.md", str!["after"]),
+            ("LICENSE", str!["after"]),
+            ("Cargo.toml", cargo_toml),
+        ],
+    );
+}
+
 #[cargo_test]
 fn issue_13695_allow_dirty_vcs_info() {
     let p = project()