From 4950951e349dec866a0b385e2a97ccd1b21828b7 Mon Sep 17 00:00:00 2001
From: Mike Hommey <mh@glandium.org>
Date: Fri, 17 May 2024 16:57:27 +0900
Subject: [PATCH 1/2] Disable preprocessor cache when doing distributed
 compilation

At the moment, it doesn't work.
---
 src/compiler/c.rs | 29 +++++++++++++++--------------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/src/compiler/c.rs b/src/compiler/c.rs
index 14f9e5d53..7bccc7032 100644
--- a/src/compiler/c.rs
+++ b/src/compiler/c.rs
@@ -382,20 +382,21 @@ where
         // Try to look for a cached preprocessing step for this compilation
         // request.
         let preprocessor_cache_mode_config = storage.preprocessor_cache_mode_config();
-        let mut preprocessor_key = if preprocessor_cache_mode_config.use_preprocessor_cache_mode {
-            preprocessor_cache_entry_hash_key(
-                &executable_digest,
-                parsed_args.language,
-                &preprocessor_and_arch_args,
-                &extra_hashes,
-                &env_vars,
-                &absolute_input_path,
-                compiler.plusplus(),
-                preprocessor_cache_mode_config,
-            )?
-        } else {
-            None
-        };
+        let mut preprocessor_key =
+            if !may_dist && preprocessor_cache_mode_config.use_preprocessor_cache_mode {
+                preprocessor_cache_entry_hash_key(
+                    &executable_digest,
+                    parsed_args.language,
+                    &preprocessor_and_arch_args,
+                    &extra_hashes,
+                    &env_vars,
+                    &absolute_input_path,
+                    compiler.plusplus(),
+                    preprocessor_cache_mode_config,
+                )?
+            } else {
+                None
+            };
         if let Some(preprocessor_key) = &preprocessor_key {
             if cache_control == CacheControl::Default {
                 if let Some(mut seekable) =

From 6b2c27dc58eefcff4bcd906864e71d39d2b138db Mon Sep 17 00:00:00 2001
From: Sylvestre Ledru <sylvestre@debian.org>
Date: Fri, 17 May 2024 16:35:01 +0200
Subject: [PATCH 2/2] document the change

---
 src/compiler/c.rs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/compiler/c.rs b/src/compiler/c.rs
index 7bccc7032..9e8db55ed 100644
--- a/src/compiler/c.rs
+++ b/src/compiler/c.rs
@@ -382,6 +382,7 @@ where
         // Try to look for a cached preprocessing step for this compilation
         // request.
         let preprocessor_cache_mode_config = storage.preprocessor_cache_mode_config();
+        // Disable preprocessor cache when doing distributed compilation
         let mut preprocessor_key =
             if !may_dist && preprocessor_cache_mode_config.use_preprocessor_cache_mode {
                 preprocessor_cache_entry_hash_key(