don't pass BUILDINFO into build script

It was causing the build script to be recompiled each time a commit was
made, even though buildinfo.txt was not changing.

rslib/BUILD.bazel

@@ -14,13 +14,12 @@ cargo_build_script(
         "PROTOC": "$(location @com_google_protobuf//:protoc)",
         "RSLIB_FTL_ROOT": "$(location @rslib_ftl//:l10n.toml)",
         "EXTRA_FTL_ROOT": "$(location @extra_ftl//:l10n.toml)",
-        "BUILDINFO": "$(location //:buildinfo.txt)",
+        "BAZEL": "1",
     },
     crate_root = "build/main.rs",
     data = [
         "//ftl",
         "backend.proto",
-        "//:buildinfo.txt",
         "@com_google_protobuf//:protoc",
         # bazel requires us to list these out separately
         "@rslib_ftl//:l10n.toml",
@@ -50,6 +49,10 @@ _anki_features = [
     "translations",
 ]
 
+_anki_rustc_env = {
+    "BUILDINFO": "$(location //:buildinfo.txt)",
+}
+
 rust_library(
     name = "anki",
     srcs = glob([
@@ -61,6 +64,7 @@ rust_library(
         "//rslib/cargo:serde_derive",
         "//rslib/cargo:serde_repr",
     ],
+    rustc_env = _anki_rustc_env,
     visibility = ["//visibility:public"],
     deps = [
         ":build_script",
@@ -121,6 +125,7 @@ rust_test(
     data = glob([
         "tests/support/**",
     ]),
+    rustc_env = _anki_rustc_env,
     deps = ["//rslib/cargo:env_logger"],
 )
 

rslib/build/main.rs

@@ -5,13 +5,14 @@ fn main() {
     mergeftl::write_ftl_files_and_fluent_rs();
     protobuf::write_backend_proto_rs();
 
-    // copy or mock buildinfo in out_dir
-    let buildinfo = if let Ok(buildinfo) = std::env::var("BUILDINFO") {
-        std::fs::read_to_string(&buildinfo).expect("buildinfo missing")
-    } else {
-        "".to_string()
-    };
-    let buildinfo_out =
-        std::path::Path::new(&std::env::var("OUT_DIR").unwrap()).join("buildinfo.txt");
-    std::fs::write(&buildinfo_out, buildinfo).unwrap();
+    // when building with cargo (eg for rust analyzer), generate a dummy BUILDINFO
+    if std::env::var("BAZEL").is_err() {
+        let buildinfo_out =
+            std::path::Path::new(&std::env::var("OUT_DIR").unwrap()).join("buildinfo.txt");
+        std::fs::write(&buildinfo_out, "").unwrap();
+        println!(
+            "cargo:rustc-env=BUILDINFO={}",
+            buildinfo_out.to_str().expect("buildinfo")
+        );
+    }
 }

rslib/src/version.rs

@@ -5,7 +5,7 @@ use lazy_static::lazy_static;
 use std::env;
 
 fn buildinfo(key: &str) -> &'static str {
-    let buildinfo = include_str!(concat!(env!("OUT_DIR"), "/buildinfo.txt"));
+    let buildinfo = include_str!(env!("BUILDINFO"));
     for line in buildinfo.split('\n') {
         let mut it = line.split(' ');
         if it.next().unwrap() == key {