From 72cd184e768f617dc069304b346c295b9ca25151 Mon Sep 17 00:00:00 2001
From: Gershom Bazerman <gershom@arista.com>
Date: Mon, 27 Feb 2023 14:13:49 -0500
Subject: [PATCH 1/2] use with compiler flags in key of cached project config

---
 .../Distribution/Client/ProjectPlanning.hs    | 23 ++++++++++---------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/cabal-install/src/Distribution/Client/ProjectPlanning.hs b/cabal-install/src/Distribution/Client/ProjectPlanning.hs
index 8d8947ae8a8..f4e1264c893 100644
--- a/cabal-install/src/Distribution/Client/ProjectPlanning.hs
+++ b/cabal-install/src/Distribution/Client/ProjectPlanning.hs
@@ -321,9 +321,17 @@ rebuildProjectConfig verbosity
                      }
                      cliConfig = do
 
+    progsearchpath <- liftIO $ getSystemSearchPath
+
+    let fileMonitorProjectConfig = newFileMonitor (distProjectCacheFile "config")
+
     fileMonitorProjectConfigKey <- do
       configPath <- getConfigFilePath projectConfigConfigFile
-      return (configPath, distProjectFile "")
+      return (configPath, distProjectFile "",
+                        (projectConfigHcFlavor, projectConfigHcPath, projectConfigHcPkg),
+                        progsearchpath,
+                        packageConfigProgramPaths,
+                        packageConfigProgramPathExtra)
 
     (projectConfig, localPackages) <-
       runRebuild distProjectRootDirectory
@@ -354,18 +362,11 @@ rebuildProjectConfig verbosity
 
   where
 
-    ProjectConfigShared { projectConfigConfigFile } =
-      projectConfigShared cliConfig
-
-    ProjectConfigShared { projectConfigIgnoreProject } =
+    ProjectConfigShared { projectConfigHcFlavor, projectConfigHcPath, projectConfigHcPkg, projectConfigIgnoreProject, projectConfigConfigFile } =
       projectConfigShared cliConfig
 
-    fileMonitorProjectConfig ::
-      FileMonitor
-        (FilePath, FilePath)
-        (ProjectConfig, [PackageSpecifier UnresolvedSourcePackage])
-    fileMonitorProjectConfig =
-      newFileMonitor (distProjectCacheFile "config")
+    PackageConfig { packageConfigProgramPaths, packageConfigProgramPathExtra } =
+      projectConfigLocalPackages cliConfig
 
     -- Read the cabal.project (or implicit config) and combine it with
     -- arguments from the command line

From 954a7ad3be2e09e7dee32b5ff355cd516c3dc43d Mon Sep 17 00:00:00 2001
From: Gershom Bazerman <gershom@arista.com>
Date: Fri, 12 May 2023 19:50:16 -0400
Subject: [PATCH 2/2] changelog

---
 changelog.d/pr-8819 | 9 +++++++++
 1 file changed, 9 insertions(+)
 create mode 100644 changelog.d/pr-8819

diff --git a/changelog.d/pr-8819 b/changelog.d/pr-8819
new file mode 100644
index 00000000000..1398a2ca648
--- /dev/null
+++ b/changelog.d/pr-8819
@@ -0,0 +1,9 @@
+synopsis: Use compiler flags for caching project config
+packages: cabal-install
+prs: #8819
+
+description: {
+
+This ensures that cached project configs with conditionals re-execute the conditional logic when the compiler changes.
+
+}