From fe3cb3d54e62a1c0199d0c79543569cc50ca247f Mon Sep 17 00:00:00 2001
From: Eric Huss <eric@huss.org>
Date: Fri, 8 Mar 2024 09:51:46 -0800
Subject: [PATCH] Use GITHUB_TOKEN in github_fast_path if available.

---
 src/cargo/sources/git/utils.rs | 11 +++++
 tests/testsuite/https.rs       | 78 ++++++++++++++++++++++++++--------
 2 files changed, 72 insertions(+), 17 deletions(-)

diff --git a/src/cargo/sources/git/utils.rs b/src/cargo/sources/git/utils.rs
index 9cb71433fcd..c3130cc6f0b 100644
--- a/src/cargo/sources/git/utils.rs
+++ b/src/cargo/sources/git/utils.rs
@@ -1413,6 +1413,7 @@ fn github_fast_path(
                 // the branch has moved.
                 if let Some(local_object) = local_object {
                     if is_short_hash_of(rev, local_object) {
+                        debug!("github fast path already has {local_object}");
                         return Ok(FastPathRev::UpToDate);
                     }
                 }
@@ -1452,12 +1453,19 @@ fn github_fast_path(
     handle.get(true)?;
     handle.url(&url)?;
     handle.useragent("cargo")?;
+    handle.follow_location(true)?; // follow redirects
     handle.http_headers({
         let mut headers = List::new();
         headers.append("Accept: application/vnd.github.3.sha")?;
         if let Some(local_object) = local_object {
             headers.append(&format!("If-None-Match: \"{}\"", local_object))?;
         }
+        if let Ok(token) = gctx.get_env("GITHUB_TOKEN") {
+            if !token.is_empty() {
+                // Avoid API rate limits if possible.
+                headers.append(&format!("Authorization: Bearer {token}"))?;
+            }
+        }
         headers
     })?;
 
@@ -1472,14 +1480,17 @@ fn github_fast_path(
 
     let response_code = handle.response_code()?;
     if response_code == 304 {
+        debug!("github fast path up-to-date");
         Ok(FastPathRev::UpToDate)
     } else if response_code == 200 {
         let oid_to_fetch = str::from_utf8(&response_body)?.parse::<Oid>()?;
+        debug!("github fast path fetch {oid_to_fetch}");
         Ok(FastPathRev::NeedsFetch(oid_to_fetch))
     } else {
         // Usually response_code == 404 if the repository does not exist, and
         // response_code == 422 if exists but GitHub is unable to resolve the
         // requested rev.
+        debug!("github fast path bad response code {response_code}");
         Ok(FastPathRev::Indeterminate)
     }
 }
diff --git a/tests/testsuite/https.rs b/tests/testsuite/https.rs
index 85a894a3198..be6ecf89076 100644
--- a/tests/testsuite/https.rs
+++ b/tests/testsuite/https.rs
@@ -4,6 +4,7 @@
 //! or CARGO_PUBLIC_NETWORK_TESTS.
 
 use cargo_test_support::containers::Container;
+use cargo_test_support::paths::{self, CargoPathExt};
 use cargo_test_support::project;
 
 #[cargo_test(container_test)]
@@ -134,22 +135,65 @@ fn self_signed_with_cacert() {
 #[cargo_test(public_network_test)]
 fn github_works() {
     // Check that an https connection to github.com works.
-    let p = project()
-        .file(
-            "Cargo.toml",
-            r#"
-                [package]
-                name = "foo"
-                version = "0.1.0"
-                edition = "2015"
+    // This tries all the different types of git references, and verifies the fast-path behavior.
+    for (manifest_ref, oid, refspecs, up_to_date) in [
+        (
+            r#", tag = "1.3.2""#,
+            "ed185cfb1c447c1b4bd6ac021c9ec3bb02c9e2f2",
+            r#""+refs/tags/1.3.2:refs/remotes/origin/tags/1.3.2""#,
+            "github fast path up-to-date",
+        ),
+        (
+            r#", rev = "6c67922300d5abae779ca147bac00f6ff9c87f8a""#,
+            "6c67922300d5abae779ca147bac00f6ff9c87f8a",
+            r#""+6c67922300d5abae779ca147bac00f6ff9c87f8a:refs/commit/6c67922300d5abae779ca147bac00f6ff9c87f8a""#,
+            "github fast path already has 6c67922300d5abae779ca147bac00f6ff9c87f8a",
+        ),
+        (
+            r#", branch = "main""#,
+            "[..]",
+            r#""+refs/heads/main:refs/remotes/origin/main""#,
+            "github fast path up-to-date",
+        ),
+        (
+            "",
+            "[..]",
+            r#""+HEAD:refs/remotes/origin/HEAD""#,
+            "github fast path up-to-date",
+        ),
+    ] {
+        eprintln!("test {manifest_ref}");
+        let p = project()
+            .file(
+                "Cargo.toml",
+                &format!(
+                    r#"
+                    [package]
+                    name = "foo"
+                    version = "0.1.0"
+                    edition = "2015"
 
-                [dependencies]
-                bitflags = { git = "https://github.com/rust-lang/bitflags.git", tag="1.3.2" }
-            "#,
-        )
-        .file("src/lib.rs", "")
-        .build();
-    p.cargo("fetch")
-        .with_stderr("[UPDATING] git repository `https://github.com/rust-lang/bitflags.git`")
-        .run();
+                    [dependencies]
+                    bitflags = {{ git = "https://github.com/rust-lang/bitflags.git"{manifest_ref}}}
+                "#
+                ),
+            )
+            .file("src/lib.rs", "")
+            .build();
+        p.cargo("fetch")
+            .env("CARGO_LOG", "cargo::sources::git::utils=debug")
+            .with_stderr_contains("[UPDATING] git repository `https://github.com/rust-lang/bitflags.git`")
+            .with_stderr_contains("[..]attempting GitHub fast path[..]")
+            .with_stderr_contains(&format!("[..]github fast path fetch {oid}"))
+            .with_stderr_contains(&format!("[..]initiating fetch of [{refspecs}] from https://github.com/rust-lang/bitflags.git"))
+            .run();
+        // Remove the lock file, and test the up-to-date code path.
+        p.root().join("Cargo.lock").rm_rf();
+        p.cargo("fetch")
+            .env("CARGO_LOG", "cargo::sources::git::utils=debug")
+            .with_stderr_contains(&format!("[..]{up_to_date}"))
+            .run();
+
+        paths::home().join(".cargo/git").rm_rf();
+    }
 }