From 7d9ad1e3d58774c06bd5b189336a8211d0caee9c Mon Sep 17 00:00:00 2001
From: Kesavan Yogeswaran <hikes@google.com>
Date: Thu, 15 Apr 2021 18:08:19 -0400
Subject: [PATCH] Bypass codegen for docs.rs build
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The codegen performed in the build script returns an error in the
docs.rs build environment, as write permissions seem to be locked down.

This PR skips the codegen steps in the build script if the `DOCS_RS`
environment variable is set.

 #### Testing

 I didn't want to pull the 10GB needed to run the Docker images that
 docs.rs uses. Instead, as a sanity check, I ran
 `cargo doc --all-features` with and without the `DOCS_RS` environment
 set and verified via strategically placed `panic!` macros that the
 build script was bypassed when the variable was set 😬

 #### References

 * <https://docs.rs/about/builds#detecting-docsrs>
 * docs.rs page: <https://docs.rs/crate/google-cloud/0.2.1>
 * Failed build: <https://docs.rs/crate/google-cloud/0.2.1/builds/366129>
---
 google-cloud/build.rs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/google-cloud/build.rs b/google-cloud/build.rs
index 7c7af44a..695cd780 100644
--- a/google-cloud/build.rs
+++ b/google-cloud/build.rs
@@ -1,6 +1,13 @@
+use std::env;
 use std::fs;
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
+    // The docs.rs build locks down write permissions and causes codegen to fail. Skip it since
+    // it's not really needed for rustdoc anyway.
+    if env::var("DOCS_RS").is_ok() {
+        return Ok(());
+    }
+
     let protos = [
         (["protos/google/pubsub/v1/pubsub.proto"], "src/pubsub/api"),
         (