Use separate representations for canonical repository vs. commit (#317)

Given `https://github.com/pypa/package.git#subdirectory=pkg_a` and
`https://github.com/pypa/package.git#subdirectory=pkg_b`, we want these
to map to the same shared _resource_ (for locking and cloning), but
different _packages_ (for determining whether the wheel already exists
in the cache). As such, we need two distinct concepts for "canonical
equality".

Closes #316.

crates/puffin-cli/tests/pip_compile.rs

@@ -885,6 +885,43 @@ fn compile_git_subdirectory_dependency() -> Result<()> {
     Ok(())
 }
 
+/// Resolve two packages from a `requirements.in` file with the same Git HTTPS dependency.
+#[test]
+fn compile_git_concurrent_access() -> Result<()> {
+    let temp_dir = assert_fs::TempDir::new()?;
+    let cache_dir = assert_fs::TempDir::new()?;
+    let venv = temp_dir.child(".venv");
+
+    Command::new(get_cargo_bin(BIN_NAME))
+        .arg("venv")
+        .arg(venv.as_os_str())
+        .arg("--cache-dir")
+        .arg(cache_dir.path())
+        .current_dir(&temp_dir)
+        .assert()
+        .success();
+    venv.assert(predicates::path::is_dir());
+
+    let requirements_in = temp_dir.child("requirements.in");
+    requirements_in.touch()?;
+    requirements_in
+        .write_str("example-pkg-a @ git+https://github.com/pypa/sample-namespace-packages.git@df7530eeb8fa0cb7dbb8ecb28363e8e36bfa2f45#subdirectory=pkg_resources/pkg_a\nexample-pkg-b @ git+https://github.com/pypa/sample-namespace-packages.git@df7530eeb8fa0cb7dbb8ecb28363e8e36bfa2f45#subdirectory=pkg_resources/pkg_b")?;
+
+    insta::with_settings!({
+        filters => INSTA_FILTERS.to_vec()
+    }, {
+        assert_cmd_snapshot!(Command::new(get_cargo_bin(BIN_NAME))
+            .arg("pip-compile")
+            .arg("requirements.in")
+            .arg("--cache-dir")
+            .arg(cache_dir.path())
+            .env("VIRTUAL_ENV", venv.as_os_str())
+            .current_dir(&temp_dir));
+    });
+
+    Ok(())
+}
+
 /// Resolve a Git dependency with a declared name that differs from the true name of the package.
 #[test]
 fn compile_git_mismatched_name() -> Result<()> {

crates/puffin-cli/tests/snapshots/pip_compile__compile_git_concurrent_access.snap

@@ -0,0 +1,23 @@
+---
+source: crates/puffin-cli/tests/pip_compile.rs
+info:
+  program: puffin
+  args:
+    - pip-compile
+    - requirements.in
+    - "--cache-dir"
+    - /var/folders/nt/6gf2v7_s3k13zq_t3944rwz40000gn/T/.tmp41ygCm
+  env:
+    VIRTUAL_ENV: /var/folders/nt/6gf2v7_s3k13zq_t3944rwz40000gn/T/.tmpBfaYxl/.venv
+---
+success: true
+exit_code: 0
+----- stdout -----
+# This file was autogenerated by Puffin v0.0.1 via the following command:
+#    [BIN_PATH] pip-compile requirements.in --cache-dir [CACHE_DIR]
+example-pkg-a @ git+https://github.com/pypa/sample-namespace-packages.git@df7530eeb8fa0cb7dbb8ecb28363e8e36bfa2f45#subdirectory=pkg_resources/pkg_a
+example-pkg-b @ git+https://github.com/pypa/sample-namespace-packages.git@df7530eeb8fa0cb7dbb8ecb28363e8e36bfa2f45#subdirectory=pkg_resources/pkg_b
+
+----- stderr -----
+Resolved 2 packages in [TIME]
+