[bug] REST catalog `namespace_exists` fails with 400 Bad Request

[dentiny]

Apache Iceberg Rust version

None

Describe the bug

Reproduce environment: https://github.com/dentiny/iceberg-rust-namespace-exists
which sets up a docker environment, with latest iceberg-rust.

Steps:

• start devcontainer
• cargo run

You should be able to see namespace_exists fails with

Error: Unexpected => Received response with unexpected status code

Context:
   status: 400 Bad Request
   headers: {"date": "Mon, 28 Apr 2025 15:28:27 GMT", "content-type": "application/json", "content-length": "112", "server": "Jetty(9.4.51.v20230217)"}

To Reproduce

Described above, and reproduce stably on my local environment.

Expected behavior

namespace_exists return a boolean true or false, not panic.

Willingness to contribute

None

[Xuanwo]

Hi, what's the output of get_namespace? I'm guessing we can have the real error output by calling get_namespace.

[dentiny]

If the namespace doesn't exist in the catalog, get_namespace returns error (which is expected)

Error: Unexpected => Tried to get a namespace that does not exist

If the namespace already exists, namespace_exists still panics wit the same error message I attached in the issue.

[dentiny]

I just push a new commit to my reproduction branch, hopefully you could easily reproduce on your end.
Let me know if it doesn't, or you need more information. Thank you for taking a look!

[dentiny]

Hi @Xuanwo , thank you for the quick response!
I just realize I didn't push my devcontainer config to the repo; it should be fixed now, and you should be easily reproduce the issue. Let me know if you're not able to reproduce it, or you need more information. Thank you again!

[Xuanwo]

If the namespace doesn't exist in the catalog, get_namespace returns error (which is expected)

Error: Unexpected => Tried to get a namespace that does not exist
If the namespace already exists, namespace_exists still panics wit the same error message I attached in the issue.

Hi, get_namespace (GET /namespace) should generate the same error with namespace_exists (HEAD /namespace). So I'm interested in what's output for get_namespace over an existing namespace.

[Xuanwo]

Hi @dentiny, I’m able to reproduce this issue on tabulario/iceberg-rest:latest (last updated 8 months ago), but not on apache/iceberg-rest-fixture:latest. Would you like to try using apache/iceberg-rest-fixture?

diff --git a/.devcontainer/docker-compose.yaml b/.devcontainer/docker-compose.yaml
index 88b1959..df7c938 100644
--- a/.devcontainer/docker-compose.yaml
+++ b/.devcontainer/docker-compose.yaml
@@ -13,5 +13,6 @@ services:
     command: ["-c", "wal_level=logical"]
 
   iceberg:
-    image: tabulario/iceberg-rest:latest
+    # image: tabulario/iceberg-rest:latest
+    image: apache/iceberg-rest-fixture:latest
     network_mode: service:postgres

[Xuanwo]

I double checked the iceberg's code. It looks like the support for namespace_exists (the HEAD request) is added 4 months ago in apache/iceberg#11761.

See also https://github.com/apache/iceberg/blame/main/core/src/test/java/org/apache/iceberg/rest/RESTCatalogAdapter.java

[Xuanwo]

cc @liurenjie1024, @Fokko Do you think it's worth making this compatible here? Should we fallback to get_namespace() if namespaces_exists fails with a 400 error?

[dentiny]

Hi @dentiny, I’m able to reproduce this issue on tabulario/iceberg-rest:latest (last updated 8 months ago), but not on apache/iceberg-rest-fixture:latest. Would you like to try using apache/iceberg-rest-fixture?

Wow thank you so much for the investigation!
Meanwhile, I'm also confused why it doesn't use 501 if unimplemented

Yeah I will use fixture image, as you suggested.

[Xuanwo]

Yeah I will use fixture image, as you suggested.

Please let me know if this issue still exists.

[dentiny]

Please let me know if this issue still exists.

It works on my side, thank you for the help!

[Xuanwo]

Let's close this issue as not planned. Feel free to open a new one if anyone think we should be compatible to rest catalog impls that doesn't support namespace_exists.