lib/src/tar/write: make sure we add the links when filtering the tar

Co-authored-by: Colin Walters <walters@verbum.org>

lib/src/tar/write.rs

@@ -156,7 +156,23 @@ pub(crate) fn filter_tar(
         };
 
         let mut header = entry.header().clone();
-        dest.append_data(&mut header, normalized, entry)?;
+
+        // Need to use the entry.link_name() not the header.link_name()
+        // api as the header api does not handle long paths:
+        // https://github.com/alexcrichton/tar-rs/issues/192
+        match entry.header().entry_type() {
+            tar::EntryType::Link | tar::EntryType::Symlink => {
+                let target = entry.link_name()?.ok_or_else(|| anyhow!("Invalid link"))?;
+                let target = target
+                    .as_os_str()
+                    .to_str()
+                    .ok_or_else(|| anyhow!("Non-utf8 link"))?;
+                dest.append_link(&mut header, &normalized, target)?;
+            }
+            _ => {
+                dest.append_data(&mut header, normalized, entry)?;
+            }
+        }
     }
     dest.into_inner()?.flush()?;
     Ok(filtered)

lib/tests/it/main.rs

@@ -15,6 +15,7 @@ use std::process::Command;
 
 use fixture::Fixture;
 
+const EXAMPLE_TAR_LAYER: &[u8] = include_bytes!("fixtures/hlinks.tar.gz");
 const EXAMPLEOS_CONTENT_CHECKSUM: &str =
     "0ef7461f9db15e1d8bd8921abf20694225fbaa4462cadf7deed8ea0e43162120";
 const TEST_REGISTRY_DEFAULT: &str = "localhost:5000";
@@ -324,6 +325,16 @@ async fn test_tar_write() -> Result<()> {
     Ok(())
 }
 
+#[tokio::test]
+async fn test_tar_write_tar_layer() -> Result<()> {
+    let fixture = Fixture::new()?;
+    let uncompressed_tar = tokio::io::BufReader::new(
+        async_compression::tokio::bufread::GzipDecoder::new(EXAMPLE_TAR_LAYER),
+    );
+    ostree_ext::tar::write_tar(&fixture.destrepo, uncompressed_tar, "test", None).await?;
+    Ok(())
+}
+
 fn skopeo_inspect(imgref: &str) -> Result<String> {
     let out = Command::new("skopeo")
         .args(&["inspect", imgref])