test(build-dir): Added test for workspace-path-hash cross Cargo version consistency

Author: ranger-ross

src/cargo/version.rs

@@ -58,28 +58,30 @@ pub fn version() -> VersionInfo {
         };
     }
 
-    // This is the version set in bootstrap, which we use to match rustc.
-    let version = option_env_str!("CFG_RELEASE").unwrap_or_else(|| {
-        // If cargo is not being built by bootstrap, then we just use the
-        // version from cargo's own `Cargo.toml`.
-        //
-        // There are two versions at play here:
-        //   - version of cargo-the-binary, which you see when you type `cargo --version`
-        //   - version of cargo-the-library, which you download from crates.io for use
-        //     in your packages.
-        //
-        // The library is permanently unstable, so it always has a 0 major
-        // version. However, the CLI now reports a stable 1.x version
-        // (starting in 1.26) which stays in sync with rustc's version.
-        //
-        // Coincidentally, the minor version for cargo-the-library is always
-        // +1 of rustc's minor version (that is, `rustc 1.11.0` corresponds to
-        // `cargo `0.12.0`). The versions always get bumped in lockstep, so
-        // this should continue to hold.
-        let minor = env!("CARGO_PKG_VERSION_MINOR").parse::<u8>().unwrap() - 1;
-        let patch = env!("CARGO_PKG_VERSION_PATCH").parse::<u8>().unwrap();
-        format!("1.{}.{}", minor, patch)
-    });
+    let version = version_for_testing()
+        // This is the version set in bootstrap, which we use to match rustc.
+        .or_else(|| option_env_str!("CFG_RELEASE"))
+        .unwrap_or_else(|| {
+            // If cargo is not being built by bootstrap, then we just use the
+            // version from cargo's own `Cargo.toml`.
+            //
+            // There are two versions at play here:
+            //   - version of cargo-the-binary, which you see when you type `cargo --version`
+            //   - version of cargo-the-library, which you download from crates.io for use
+            //     in your packages.
+            //
+            // The library is permanently unstable, so it always has a 0 major
+            // version. However, the CLI now reports a stable 1.x version
+            // (starting in 1.26) which stays in sync with rustc's version.
+            //
+            // Coincidentally, the minor version for cargo-the-library is always
+            // +1 of rustc's minor version (that is, `rustc 1.11.0` corresponds to
+            // `cargo `0.12.0`). The versions always get bumped in lockstep, so
+            // this should continue to hold.
+            let minor = env!("CARGO_PKG_VERSION_MINOR").parse::<u8>().unwrap() - 1;
+            let patch = env!("CARGO_PKG_VERSION_PATCH").parse::<u8>().unwrap();
+            format!("1.{}.{}", minor, patch)
+        });
 
     let release_channel = option_env_str!("CFG_RELEASE_CHANNEL");
     let commit_info = option_env_str!("CARGO_COMMIT_HASH").map(|commit_hash| CommitInfo {
@@ -96,3 +98,11 @@ pub fn version() -> VersionInfo {
         description,
     }
 }
+
+/// Provides a way for tests to inject an abitrary version for testing purposes.
+///
+// __CARGO_TEST_CARGO_VERSION should not be relied on outside of tests.
+#[allow(clippy::disallowed_methods)]
+fn version_for_testing() -> Option<String> {
+    std::env::var("__CARGO_TEST_CARGO_VERSION").ok()
+}

tests/testsuite/build_dir.rs

@@ -609,6 +609,65 @@ fn template_workspace_path_hash() {
     assert_exists(&p.root().join(&format!("target-dir/debug/foo{EXE_SUFFIX}")));
 }
 
+#[cargo_test]
+fn template_workspace_path_hash_should_not_change_between_cargo_versions() {
+    let p = project()
+        .file("src/main.rs", r#"fn main() { println!("Hello, World!") }"#)
+        .file(
+            "Cargo.toml",
+            r#"
+            [package]
+            name = "foo"
+            version = "1.0.0"
+            authors = []
+            edition = "2015"
+            "#,
+        )
+        .file(
+            ".cargo/config.toml",
+            r#"
+            [build]
+            build-dir = "foo/{workspace-path-hash}/build-dir"
+            target-dir = "target-dir"
+            "#,
+        )
+        .build();
+
+    p.cargo("build -Z build-dir")
+        .env("__CARGO_TEST_CARGO_VERSION", "1.0.0")
+        .masquerade_as_nightly_cargo(&["build-dir"])
+        .enable_mac_dsym()
+        .run();
+
+    let foo_dir = p.root().join("foo");
+    assert_exists(&foo_dir);
+    let hash_dir = parse_workspace_manifest_path_hash(&foo_dir);
+
+    let first_run_build_dir = hash_dir.as_path().join("build-dir");
+    assert_build_dir_layout(first_run_build_dir.clone(), "debug");
+
+    // Remove the build-dir since we already know the hash and it makes
+    // finding the directory in the next run simpler.
+    foo_dir.as_path().rm_rf();
+
+    // Run Cargo build again with a different Cargo version
+    p.cargo("build -Z build-dir")
+        .env("__CARGO_TEST_CARGO_VERSION", "1.1.0")
+        .masquerade_as_nightly_cargo(&["build-dir"])
+        .enable_mac_dsym()
+        .run();
+
+    let hash_dir = parse_workspace_manifest_path_hash(&foo_dir);
+    let second_run_build_dir = hash_dir.as_path().join("build-dir");
+    assert_build_dir_layout(second_run_build_dir.clone(), "debug");
+
+    // Finally check that the build-dir is in the same location between both Cargo versions
+    assert_eq!(
+        first_run_build_dir, second_run_build_dir,
+        "The workspace path hash generated between 2 Cargo versions did not match"
+    );
+}
+
 fn parse_workspace_manifest_path_hash(hash_dir: &PathBuf) -> PathBuf {
     // Since the hash will change between test runs simply find the first directories and assume
     // that is the hash dir. The format is a 2 char directory followed by the remaining hash in the