gen_rust_project creates invalid entries if compile_data is used

[hauserx]

Generated rust-project.json started to contain include_dirs which points to bin directory. Because of that rust_analyzer does not treat any file, other than root_module, as belonging to the crate.

Workaround is to manually remove the source entry, or add appropriate include dir to rust-project.json ("src" in below example).

Bisect pointed to #3176, although reading through it possibly issue was present even before that if crate contained some generated data.

Example on https://github.com/cameron-martin/bazel-lsp after bazel run @rules_rust//tools/rust_analyzer:gen_rust_project

  "crates": [
...
    {
      "display_name": "bazel_lsp",
      "root_module": "/home/hauser/repos/bazel-lsp/src/main.rs",
...
      "source": {
        "include_dirs": [
          "/home/hauser/.cache/bazel/_bazel_hauser/7b35979d7249c8686e26265de57e7009/execroot/_main/bazel-out/k8-fastbuild/bin/src"
        ],
        "exclude_dirs": []
      },
...

[UebelAndre]

Bisect pointed to #3176, although reading through it possibly issue was present even before that if crate contained some generated data.

I'm confused, did this introduce an additional regression or not? If so I think we should revert it.

[hauserx]

Yes, it stopped working for bazel-lsp that is using compile_data.

But I am not sure it worked even before if some generated data was used - or how it worked as in such case the sources also were transformed. I have not checked it for generated data though.

[hauserx]

Just confirmed, that generated data would trigger this issue even before the #3176 .

Here is small patch on current bazel-lsp that triggers the same issue on rules_rust 0.56:

diff --git a/BUILD b/BUILD
index a52b298..b57465d 100644
--- a/BUILD
+++ b/BUILD
@@ -2,7 +2,7 @@ load("@rules_rust//rust:defs.bzl", "rust_binary", "rust_test")

 rust_binary(
     name = "bazel-lsp",
-    srcs = glob(["src/**/*.rs"]),
+    srcs = glob(["src/**/*.rs"]) + ["src/empty.rs"],
     compile_data = [
         "//src/builtin:builtin.pb",
         "//src/builtin:default_build_language.pb",
@@ -31,6 +31,12 @@ rust_binary(
     ],
 )

+genrule(
+    name = "gen_empty_file",
+    cmd = "echo  > $@",
+    outs = [ "src/empty.rs" ],
+)
+
 genrule(
     name = "generate_rustc_env_file",
     srcs = [
diff --git a/MODULE.bazel b/MODULE.bazel
index 19049d3..f46ba5e 100644
--- a/MODULE.bazel
+++ b/MODULE.bazel
@@ -1,5 +1,5 @@
-bazel_dep(name = "rules_rust", version = "0.57.0")
-bazel_dep(name = "rules_rust_prost", version = "0.57.0")
+bazel_dep(name = "rules_rust", version = "0.56.0")
+bazel_dep(name = "rules_rust_prost", version = "0.56.0")

 rust = use_extension("@rules_rust//rust:extensions.bzl", "rust")
 rust.toolchain(

[martingms]

There are a few general issues with generated sources/compile_data (especially when mixed with non-generated) in relation to rust-analyzer that is a bit unclear how to address, see #3126 for example. Afaict #3176 made builds work in more cases, but also exposed more cases where gen_rust_project generates wrong or useless rust-project.json-entries.. :/