Allow duplicate URLs that resolve to the same canonical URL (#1877)

Closes #1865.

Closes #1866.

crates/uv-resolver/src/resolver/urls.rs

@@ -28,11 +28,15 @@ impl Urls {
 
             if let Some(pep508_rs::VersionOrUrl::Url(url)) = &requirement.version_or_url {
                 if let Some(previous) = urls.insert(requirement.name.clone(), url.clone()) {
-                    return Err(ResolveError::ConflictingUrlsDirect(
-                        requirement.name.clone(),
-                        previous.verbatim().to_string(),
-                        url.verbatim().to_string(),
-                    ));
+                    if cache_key::CanonicalUrl::new(previous.raw())
+                        != cache_key::CanonicalUrl::new(url.raw())
+                    {
+                        return Err(ResolveError::ConflictingUrlsDirect(
+                            requirement.name.clone(),
+                            previous.verbatim().to_string(),
+                            url.verbatim().to_string(),
+                        ));
+                    }
                 }
             }
         }
@@ -42,21 +46,29 @@ impl Urls {
             if let Some(previous) =
                 urls.insert(metadata.name.clone(), editable_requirement.url.clone())
             {
-                return Err(ResolveError::ConflictingUrlsDirect(
-                    metadata.name.clone(),
-                    previous.verbatim().to_string(),
-                    editable_requirement.url.verbatim().to_string(),
-                ));
+                if cache_key::CanonicalUrl::new(previous.raw())
+                    != cache_key::CanonicalUrl::new(editable_requirement.raw())
+                {
+                    return Err(ResolveError::ConflictingUrlsDirect(
+                        metadata.name.clone(),
+                        previous.verbatim().to_string(),
+                        editable_requirement.url.verbatim().to_string(),
+                    ));
+                }
             }
 
             for req in &metadata.requires_dist {
                 if let Some(pep508_rs::VersionOrUrl::Url(url)) = &req.version_or_url {
                     if let Some(previous) = urls.insert(req.name.clone(), url.clone()) {
-                        return Err(ResolveError::ConflictingUrlsDirect(
-                            req.name.clone(),
-                            previous.verbatim().to_string(),
-                            url.verbatim().to_string(),
-                        ));
+                        if cache_key::CanonicalUrl::new(previous.raw())
+                            != cache_key::CanonicalUrl::new(url.raw())
+                        {
+                            return Err(ResolveError::ConflictingUrlsDirect(
+                                req.name.clone(),
+                                previous.verbatim().to_string(),
+                                url.verbatim().to_string(),
+                            ));
+                        }
                     }
                 }
             }

crates/uv/tests/pip_compile.rs

@@ -1363,6 +1363,30 @@ fn conflicting_transitive_url_dependency() -> Result<()> {
     Ok(())
 }
 
+/// Request Werkzeug via two different URLs which resolve to the same canonical version.
+#[test]
+fn compatible_repeated_url_dependency() -> Result<()> {
+    let context = TestContext::new("3.12");
+    let requirements_in = context.temp_dir.child("requirements.in");
+    requirements_in.write_str("werkzeug @ git+https://github.com/pallets/[email protected]\nwerkzeug @ git+https://github.com/pallets/[email protected]")?;
+
+    uv_snapshot!(context.compile()
+            .arg("requirements.in"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    # This file was autogenerated by uv via the following command:
+    #    uv pip compile --cache-dir [CACHE_DIR] --exclude-newer 2023-11-18T12:00:00Z requirements.in
+    werkzeug @ git+https://github.com/pallets/werkzeug@af160e0b6b7ddd81c22f1652c728ff5ac72d5c74
+
+    ----- stderr -----
+    Resolved 1 package in [TIME]
+    "###
+    );
+
+    Ok(())
+}
+
 /// Request `transitive_url_dependency`, which depends on `git+https://github.com/pallets/[email protected]`.
 /// Since this URL isn't declared upfront, we should reject it.
 #[test]