Auto merge of #10281 - Gnurfos:depinfo_relative, r=ehuss

Fix use of .. in dep-info-basedir

### Summary

This allows setting, in .cargo/config's dep-info-basedir, some relative path that goes above the crate's directory.

### Motivation

In a setup like this:

```
repo_root
├── Makefile
├── some_c_things
│   └── foo.c
└── rust_things
    ├── Cargo.toml
    └─── src
        └── lib.rs
```

If you want the generated .d files to be includable directly in the Makefile (without post-processing), you need them to mention paths relative to the root, like:

rust_things/target/....: rust_things/src/lib.rs

### Implementation

For this you need to have relative paths with parent directories (in this case ..) in dep-info-basedir, which does not work without the change in this PR (due to render_filename doing only strip_prefix, while the basedir still contains literal ..s).

Let me know if this change is acceptable. Another implementation could be to canonicalize in ConfigRelativePath::resolve_path instead, especially since that struct outputs absolute paths. But that would have it access the filesystem, while it currently doesn't.

src/cargo/core/compiler/output_depinfo.rs

@@ -22,6 +22,7 @@
 //! dependencies are not included under the assumption that changes to them can
 //! be detected via changes to `Cargo.lock`.
 
+use cargo_util::paths::normalize_path;
 use std::collections::{BTreeSet, HashSet};
 use std::io::{BufWriter, Write};
 use std::path::{Path, PathBuf};
@@ -33,16 +34,21 @@ use log::debug;
 
 fn render_filename<P: AsRef<Path>>(path: P, basedir: Option<&str>) -> CargoResult<String> {
     let path = path.as_ref();
-    let relpath = match basedir {
-        None => path,
-        Some(base) => match path.strip_prefix(base) {
-            Ok(relpath) => relpath,
-            _ => path,
-        },
-    };
-    relpath
-        .to_str()
-        .ok_or_else(|| internal(format!("path `{:?}` not utf-8", relpath)))
+    if let Some(basedir) = basedir {
+        let norm_path = normalize_path(path);
+        let norm_basedir = normalize_path(basedir.as_ref());
+        match norm_path.strip_prefix(norm_basedir) {
+            Ok(relpath) => wrap_path(relpath),
+            _ => wrap_path(path),
+        }
+    } else {
+        wrap_path(path)
+    }
+}
+
+fn wrap_path(path: &Path) -> CargoResult<String> {
+    path.to_str()
+        .ok_or_else(|| internal(format!("path `{:?}` not utf-8", path)))
         .map(|f| f.replace(" ", "\\ "))
 }
 

tests/testsuite/build_script.rs

@@ -4,7 +4,7 @@ use cargo_test_support::compare::assert_match_exact;
 use cargo_test_support::paths::CargoPathExt;
 use cargo_test_support::registry::Package;
 use cargo_test_support::tools;
-use cargo_test_support::{basic_manifest, cross_compile, is_coarse_mtime, project};
+use cargo_test_support::{basic_manifest, cross_compile, is_coarse_mtime, project, project_in};
 use cargo_test_support::{rustc_host, sleep_ms, slow_cpu_multiplier, symlink_supported};
 use cargo_util::paths::remove_dir_all;
 use std::env;
@@ -3178,6 +3178,69 @@ fn generate_good_d_files() {
         .any(|v| v == "barkbarkbark" || v == "build.rs"));
 }
 
+#[cargo_test]
+fn generate_good_d_files_for_external_tools() {
+    // This tests having a relative paths going out of the
+    // project root in config's dep-info-basedir
+    let p = project_in("rust_things")
+        .file(
+            "awoo/Cargo.toml",
+            r#"
+                [project]
+                name = "awoo"
+                version = "0.5.0"
+                build = "build.rs"
+            "#,
+        )
+        .file("awoo/src/lib.rs", "")
+        .file(
+            "awoo/build.rs",
+            r#"
+                fn main() {
+                    println!("cargo:rerun-if-changed=build.rs");
+                    println!("cargo:rerun-if-changed=barkbarkbark");
+                }
+            "#,
+        )
+        .file(
+            "Cargo.toml",
+            r#"
+                [project]
+                name = "meow"
+                version = "0.5.0"
+                [dependencies]
+                awoo = { path = "awoo" }
+            "#,
+        )
+        .file("src/main.rs", "fn main() {}")
+        .file(
+            ".cargo/config.toml",
+            r#"
+                [build]
+                dep-info-basedir="../.."
+            "#,
+        )
+        .build();
+
+    p.cargo("build -v").run();
+
+    let dot_d_path = p.bin("meow").with_extension("d");
+    let dot_d = fs::read_to_string(&dot_d_path).unwrap();
+
+    println!("*.d file content with dep-info-basedir*: {}", &dot_d);
+
+    assert_match_exact(
+        concat!(
+            "rust_things/foo/target/debug/meow[EXE]:",
+            " rust_things/foo/awoo/barkbarkbark",
+            " rust_things/foo/awoo/build.rs",
+            " rust_things/foo/awoo/src/lib.rs",
+            " rust_things/foo/src/main.rs",
+        ),
+        &dot_d,
+    );
+}
+
 #[cargo_test]
 fn rebuild_only_on_explicit_paths() {
     let p = project()