fix(py_venv): Implement collision handling

Cargo.Bazel.lock

@@ -1,5 +1,5 @@
 {
-  "checksum": "eb371dc49c5639c18e7f0415686de673ae7f83a972b6fd8823550485f5f63bea",
+  "checksum": "81528401c6d6fde79ca22def4e50d7ebc47f7f182a83a106d38e9e1279da39a5",
   "crates": {
     "addr2line 0.24.2": {
       "name": "addr2line",
@@ -10864,6 +10864,10 @@
               "id": "relative-path 1.9.3",
               "target": "relative_path"
             },
+            {
+              "id": "sha256 1.6.0",
+              "target": "sha256"
+            },
             {
               "id": "tempfile 3.13.0",
               "target": "tempfile"
@@ -16836,6 +16840,83 @@
       ],
       "license_file": "LICENSE-APACHE"
     },
+    "sha256 1.6.0": {
+      "name": "sha256",
+      "version": "1.6.0",
+      "package_url": "https://github.com/baoyachi/sha256-rs",
+      "repository": {
+        "Http": {
+          "url": "https://static.crates.io/crates/sha256/1.6.0/download",
+          "sha256": "f880fc8562bdeb709793f00eb42a2ad0e672c4f883bbe59122b926eca935c8f6"
+        }
+      },
+      "targets": [
+        {
+          "Library": {
+            "crate_name": "sha256",
+            "crate_root": "src/lib.rs",
+            "srcs": {
+              "allow_empty": true,
+              "include": [
+                "**/*.rs"
+              ]
+            }
+          }
+        }
+      ],
+      "library_target_name": "sha256",
+      "common_attrs": {
+        "compile_data_glob": [
+          "**"
+        ],
+        "crate_features": {
+          "common": [
+            "async",
+            "default",
+            "tokio"
+          ],
+          "selects": {}
+        },
+        "deps": {
+          "common": [
+            {
+              "id": "bytes 1.8.0",
+              "target": "bytes"
+            },
+            {
+              "id": "hex 0.4.3",
+              "target": "hex"
+            },
+            {
+              "id": "sha2 0.10.8",
+              "target": "sha2"
+            },
+            {
+              "id": "tokio 1.41.0",
+              "target": "tokio"
+            }
+          ],
+          "selects": {}
+        },
+        "edition": "2018",
+        "proc_macro_deps": {
+          "common": [
+            {
+              "id": "async-trait 0.1.83",
+              "target": "async_trait"
+            }
+          ],
+          "selects": {}
+        },
+        "version": "1.6.0"
+      },
+      "license": "MIT OR Apache-2.0",
+      "license_ids": [
+        "Apache-2.0",
+        "MIT"
+      ],
+      "license_file": "LICENSE-APACHE"
+    },
     "shell-escape 0.1.5": {
       "name": "shell-escape",
       "version": "0.1.5",
@@ -27627,6 +27708,7 @@
     "miette 7.2.0",
     "pathdiff 0.2.3",
     "relative-path 1.9.3",
+    "sha256 1.6.0",
     "tempfile 3.13.0",
     "thiserror 1.0.65",
     "uv-cache 0.0.1",

py/tests/py_venv_conflict/BUILD.bazel

@@ -0,0 +1,41 @@
+load("@bazel_skylib//rules:build_test.bzl", "build_test")
+load("//py/unstable:defs.bzl", "py_venv")
+
+py_venv(
+    name = "test_venv_error",
+    package_collisions = "error",
+    tags = [
+        "known-to-fail",
+        "manual",
+    ],
+    deps = [
+        "//py/tests/py_venv_conflict/a",
+        "//py/tests/py_venv_conflict/b",
+    ],
+)
+
+py_venv(
+    name = "test_venv_warning",
+    package_collisions = "warning",
+    deps = [
+        "//py/tests/py_venv_conflict/a",
+        "//py/tests/py_venv_conflict/b",
+    ],
+)
+
+py_venv(
+    name = "test_venv_ignore",
+    package_collisions = "ignore",
+    deps = [
+        "//py/tests/py_venv_conflict/a",
+        "//py/tests/py_venv_conflict/b",
+    ],
+)
+
+build_test(
+    name = "py_venv_conflict",
+    targets = [
+        ":test_venv_warning",
+        ":test_venv_ignore",
+    ],
+)

py/tests/py_venv_conflict/a/BUILD.bazel

@@ -0,0 +1,13 @@
+load("//py:defs.bzl", "py_library")
+
+py_library(
+    name = "a",
+    srcs = [
+        "site-packages/conflict.py",
+        "site-packages/noconflict.py",
+    ],
+    imports = [
+        "site-packages",
+    ],
+    visibility = ["//py/tests/py_venv_conflict:__pkg__"],
+)

py/tests/py_venv_conflict/a/site-packages/conflict.py

@@ -0,0 +1,4 @@
+#!/usr/bin/env python3
+
+def conflict():
+    return "a"

py/tests/py_venv_conflict/a/site-packages/noconflict.py

@@ -0,0 +1,4 @@
+#!/usr/bin/env python3
+
+def noconflict():
+    return 1

py/tests/py_venv_conflict/b/BUILD.bazel

@@ -0,0 +1,13 @@
+load("//py:defs.bzl", "py_library")
+
+py_library(
+    name = "b",
+    srcs = [
+        "site-packages/conflict.py",
+        "site-packages/noconflict.py",
+    ],
+    imports = [
+        "site-packages",
+    ],
+    visibility = ["//py/tests/py_venv_conflict:__pkg__"],
+)

py/tests/py_venv_conflict/b/site-packages/conflict.py

@@ -0,0 +1,4 @@
+#!/usr/bin/env python3
+
+def conflict():
+    return "b"

py/tests/py_venv_conflict/b/site-packages/noconflict.py

@@ -0,0 +1,4 @@
+#!/usr/bin/env python3
+
+def noconflict():
+    return 1

py/tools/py/BUILD.bazel

@@ -22,6 +22,7 @@ rust_library(
         "@crate_index//:itertools",
         "@crate_index//:miette",
         "@crate_index//:pathdiff",
+        "@crate_index//:sha256",
         "@crate_index//:tempfile",
         "@crate_index//:thiserror",
         "@crate_index//:uv-cache",

py/tools/py/Cargo.toml

@@ -19,6 +19,7 @@ itertools = { workspace = true }
 miette = { workspace = true }
 pathdiff = "0.2.3"
 relative-path = "1.9.3"
+sha256 = "1.6.0"
 tempfile = { workspace = true }
 thiserror = { workspace = true }
 uv-cache = { workspace = true }

py/tools/py/src/lib.rs

@@ -5,4 +5,4 @@ pub mod venv;
 pub use unpack::unpack_wheel;
 pub use venv::create_venv;
 
-pub use pth::{PthFile, SymlinkCollisionResolutionStrategy};
+pub use pth::{CollisionResolutionStrategy, PthFile};

py/tools/py/src/pth.rs

@@ -31,8 +31,8 @@ from .runfiles import *
 
 /// Strategy that will be used when creating the virtual env symlink and
 /// a collision is found.
-#[derive(Default, Debug)]
-pub enum SymlinkCollisionResolutionStrategy {
+#[derive(Default, Debug, PartialEq)]
+pub enum CollisionResolutionStrategy {
     /// Collisions cause a hard error.
     #[default]
     Error,
@@ -49,7 +49,7 @@ pub struct SitePackageOptions {
     pub dest: PathBuf,
 
     /// Collision strategy determining the action taken when sylinks in the venv collide.
-    pub collision_strategy: SymlinkCollisionResolutionStrategy,
+    pub collision_strategy: CollisionResolutionStrategy,
 }
 
 pub struct PthFile {
@@ -121,7 +121,7 @@ pub fn create_symlinks(
     dir: &Path,
     root_dir: &Path,
     dst_dir: &Path,
-    collision_strategy: &SymlinkCollisionResolutionStrategy,
+    collision_strategy: &CollisionResolutionStrategy,
 ) -> miette::Result<()> {
     // Create this directory at the destination.
     let tgt_dir = dst_dir.join(dir.strip_prefix(root_dir).unwrap());
@@ -176,7 +176,7 @@ fn create_symlink(
     e: &DirEntry,
     root_dir: &Path,
     dst_dir: &Path,
-    collision_strategy: &SymlinkCollisionResolutionStrategy,
+    collision_strategy: &CollisionResolutionStrategy,
 ) -> miette::Result<()> {
     let tgt = e.path();
     let link = dst_dir.join(tgt.strip_prefix(root_dir).unwrap());
@@ -232,7 +232,7 @@ fn create_symlink(
         }
 
         match collision_strategy {
-            SymlinkCollisionResolutionStrategy::LastWins(warn) => {
+            CollisionResolutionStrategy::LastWins(warn) => {
                 fs::remove_file(&link)
                     .into_diagnostic()
                     .wrap_err(
@@ -248,7 +248,7 @@ fn create_symlink(
                     eprintln!("{:?}", conflicts);
                 }
             }
-            SymlinkCollisionResolutionStrategy::Error => {
+            CollisionResolutionStrategy::Error => {
                 // If the link already exists, then there is going to be a conflict.
                 let conflicts = conflict_report(&link, &tgt, Severity::Error);
                 return Err(conflicts);