From 02a1c891a626bc22656d064f2a31e5e141b7c3bc Mon Sep 17 00:00:00 2001
From: Damien Elmes <gpg@ankiweb.net>
Date: Thu, 15 Jun 2023 22:32:16 +1000
Subject: [PATCH] Don't require DESCRIPTORS_BIN in an external workspace

Consumers may not require it
---
 rslib/proto/build.rs |  5 ++---
 rslib/proto/rust.rs  | 16 +++++++++-------
 2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/rslib/proto/build.rs b/rslib/proto/build.rs
index f4141084a..5d88a1b15 100644
--- a/rslib/proto/build.rs
+++ b/rslib/proto/build.rs
@@ -9,13 +9,12 @@ pub mod utils;
 use std::env;
 use std::path::PathBuf;
 
-use anyhow::Context;
 use anyhow::Result;
 
 fn main() -> Result<()> {
-    let descriptors_path = PathBuf::from(env::var("DESCRIPTORS_BIN").context("DESCRIPTORS_BIN")?);
+    let descriptors_path = env::var("DESCRIPTORS_BIN").ok().map(PathBuf::from);
 
-    let pool = rust::write_backend_proto_rs(&descriptors_path)?;
+    let pool = rust::write_backend_proto_rs(descriptors_path)?;
     python::write_python_interface(&pool)?;
     ts::write_ts_interface(&pool)?;
 
diff --git a/rslib/proto/rust.rs b/rslib/proto/rust.rs
index e4011c63b..03d8a0f15 100644
--- a/rslib/proto/rust.rs
+++ b/rslib/proto/rust.rs
@@ -14,16 +14,11 @@ use anyhow::Result;
 use prost_build::ServiceGenerator;
 use prost_reflect::DescriptorPool;
 
-pub fn write_backend_proto_rs(descriptors_path: &Path) -> Result<DescriptorPool> {
+pub fn write_backend_proto_rs(descriptors_path: Option<PathBuf>) -> Result<DescriptorPool> {
     set_protoc_path();
     let proto_dir = PathBuf::from("../../proto");
     let paths = gather_proto_paths(&proto_dir)?;
     let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());
-    create_dir_all(
-        descriptors_path
-            .parent()
-            .context("missing parent of descriptor")?,
-    )?;
     let tmp_descriptors = out_dir.join("descriptors.tmp");
     prost_build::Config::new()
         .out_dir(&out_dir)
@@ -55,7 +50,14 @@ pub fn write_backend_proto_rs(descriptors_path: &Path) -> Result<DescriptorPool>
         .context("prost build")?;
 
     let descriptors = read_file(&tmp_descriptors)?;
-    write_file_if_changed(descriptors_path, &descriptors)?;
+    if let Some(descriptors_path) = descriptors_path {
+        create_dir_all(
+            descriptors_path
+                .parent()
+                .context("missing parent of descriptor")?,
+        )?;
+        write_file_if_changed(descriptors_path, &descriptors)?;
+    }
     write_service_index(&out_dir, descriptors)
 }