nix: dont install fake binaries and fix dirty jj version

build.rs

@@ -37,6 +37,12 @@ fn main() -> std::io::Result<()> {
 }
 
 fn get_git_hash() -> Option<String> {
+    if let Some(nix_hash) = std::env::var("NIX_JJ_GIT_HASH")
+        .ok()
+        .filter(|s| !s.is_empty())
+    {
+        return Some(nix_hash);
+    }
     if let Ok(output) = Command::new("jj")
         .args([
             "--ignore-working-copy",

flake.nix

@@ -41,6 +41,8 @@
           version = "unstable-${self.shortRev or "dirty"}";
           buildNoDefaultFeatures = true;
           buildFeatures = [];
+          cargoBuildFlags = ["--bin" "jj"]; # don't build and install the fake editors
+          useNextest = true;
           src = filterSrc ./. [
             ".*\\.nix$"
             "^.jj/"
@@ -64,6 +66,7 @@
             ];
           ZSTD_SYS_USE_PKG_CONFIG = "1";
           LIBSSH2_SYS_USE_PKG_CONFIG = "1";
+          NIX_JJ_GIT_HASH = self.rev or "";
           postInstall = ''
             $out/bin/jj util mangen > ./jj.1
             installManPage ./jj.1
@@ -106,6 +109,9 @@
           openssl zstd libgit2 libssh2
           pkg-config
 
+          # Make sure rust-analyzer is present
+          rust-analyzer
+
           # Additional tools recommended by contributing.md
           cargo-deny
           cargo-insta