From 3e5a9ad7ff15e5263d8b31288095ebd2e489b8e1 Mon Sep 17 00:00:00 2001
From: "lincoln auster [they/them]" <lincolnauster@gmail.com>
Date: Thu, 13 Jan 2022 13:01:04 -0700
Subject: [PATCH] allow modifying lockfile commit msg with nix config option

This allows setting the commit-lockfile-summary option to a non-empty
string to override the commit summary while leaving the body unchanged.
---
 src/libexpr/flake/flake.cc | 20 ++++++++++++++++----
 src/libstore/globals.hh    |  7 +++++++
 2 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/src/libexpr/flake/flake.cc b/src/libexpr/flake/flake.cc
index 190a128d7..0fbe9b960 100644
--- a/src/libexpr/flake/flake.cc
+++ b/src/libexpr/flake/flake.cc
@@ -633,12 +633,24 @@ LockedFlake lockFlake(
 
                         newLockFile.write(path);
 
+                        std::optional<std::string> commitMessage = std::nullopt;
+                        if (lockFlags.commitLockFile) {
+                            std::string cm;
+
+                            cm = settings.commitLockFileSummary.get();
+
+                            if (cm == "") {
+                                cm = fmt("%s: %s", relPath, lockFileExists ? "Update" : "Add");
+                            }
+
+                            cm += "\n\nFlake lock file updates:\n\n";
+                            cm += filterANSIEscapes(diff, true);
+                            commitMessage = cm;
+                        }
+
                         topRef.input.markChangedFile(
                             (topRef.subdir == "" ? "" : topRef.subdir + "/") + "flake.lock",
-                            lockFlags.commitLockFile
-                            ? std::optional<std::string>(fmt("%s: %s\n\nFlake lock file changes:\n\n%s",
-                                    relPath, lockFileExists ? "Update" : "Add", filterANSIEscapes(diff, true)))
-                            : std::nullopt);
+                            commitMessage);
 
                         /* Rewriting the lockfile changed the top-level
                            repo, so we should re-read it. FIXME: we could
diff --git a/src/libstore/globals.hh b/src/libstore/globals.hh
index 1911ec855..f65893b10 100644
--- a/src/libstore/globals.hh
+++ b/src/libstore/globals.hh
@@ -966,6 +966,13 @@ public:
 
     Setting<bool> acceptFlakeConfig{this, false, "accept-flake-config",
         "Whether to accept nix configuration from a flake without prompting."};
+
+    Setting<std::string> commitLockFileSummary{
+        this, "", "commit-lockfile-summary",
+        R"(
+          The commit summary to use when commiting changed flake lock files. If
+          empty, the summary is generated based on the action performed.
+        )"};
 };