rust-project.json points to non-existing file

[otiv-willem-vanhulle]

When I run

bazel run @rules_rust//tools/rust_analyzer:gen_rust_project

in my Bazel/Rust project, the generated rust-project.json contains an entry for an code-generated crate, but the path in root_module of the crate entry does not exist. Removing the rust_project.json and re-running it doesn't fix it. I have tried disabling the disk_cache, but the command above still generates the wrong root_module.

This is an example output

{
  "sysroot": "/home/wvhulle/.cache/bazel/_bazel_wvhulle/2f024897ff0f2736b273e0e86d0d74ec//external/rules_rust~~rust~rust_analyzer_1.80.0_tools",
  "sysroot_src": "/home/wvhulle/.cache/bazel/_bazel_wvhulle/2f024897ff0f2736b273e0e86d0d74ec/external/rules_rust~~rust~rust_analyzer_1.80.0_tools/lib/rustlib/src/library",
  "crates": [
    {
      "display_name": "middleware_messages",
      "root_module": "/home/wvhulle/.cache/bazel/_bazel_wvhulle/2f024897ff0f2736b273e0e86d0d74ec/execroot/_main/bazel-out/k8-fastbuild/bin/otiv3/middleware_types/middleware_messages.lib.rs",
      "edition": "2021",
      "deps": [],
      "is_workspace_member": true,
      "cfg": [
        "test",
        "debug_assertions"
      ],}]}

The file /home/wvhulle/.cache/bazel/_bazel_wvhulle/2f024897ff0f2736b273e0e86d0d74ec/execroot/_main/bazel-out/k8-fastbuild/bin/otiv3/middleware_types/middleware_messages.lib.rs does not exist although the target can be build without problem.

I have tried to disable the disk cache completely, removing the disk cache at ~/.cache/bazel completely and also changing the location with --disk_cache=~/.cache/bazel_disk_cache.

It seems like the wrong path is generated pointing to a non-existing location in the cache. Sometimes it suddenly works, but often it is just broken and I don't understand why.

[otiv-willem-vanhulle]

I seem to make some progress if remove all disk cache options from .bazelrc: common --disk_cache=~/.cache/bazel_disk_cache. It seems like there is a bug that causes the rust-project.json not to detect the usage of an alternative disk_cache. When I don't specify the cache and start from a clean state, things seem to work at first sight.