From 645f4bc5ca28d56599c09c3a0526bf444b34ad31 Mon Sep 17 00:00:00 2001
From: Alexander Wang <alex@terrastruct.com>
Date: Sat, 5 Oct 2024 16:33:48 -0600
Subject: [PATCH 1/2] atomic writes

---
 d2cli/main.go | 15 ++++++++++++---
 go.mod        |  2 +-
 go.sum        |  4 ++--
 3 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/d2cli/main.go b/d2cli/main.go
index 4afe5fba5..df66926fa 100644
--- a/d2cli/main.go
+++ b/d2cli/main.go
@@ -537,7 +537,7 @@ func compile(ctx context.Context, ms *xmain.State, plugins []d2plugin.Plugin, fs
 		if err != nil {
 			return nil, false, err
 		}
-		err = ms.WritePath(outputPath, out)
+		err = Write(ms, outputPath, out)
 		if err != nil {
 			return nil, false, err
 		}
@@ -621,7 +621,7 @@ func compile(ctx context.Context, ms *xmain.State, plugins []d2plugin.Plugin, fs
 				if err != nil {
 					return nil, false, err
 				}
-				err = ms.WritePath(outputPath, out)
+				err = Write(ms, outputPath, out)
 				if err != nil {
 					return nil, false, err
 				}
@@ -906,7 +906,7 @@ func _render(ctx context.Context, ms *xmain.State, plugin d2plugin.Plugin, opts
 		if err != nil {
 			return svg, err
 		}
-		err = ms.WritePath(outputPath, out)
+		err = Write(ms, outputPath, out)
 		if err != nil {
 			return svg, err
 		}
@@ -1369,6 +1369,15 @@ func AnimatePNGs(ms *xmain.State, pngs [][]byte, animIntervalMs int) ([]byte, er
 	return xgif.AnimatePNGs(pngs, animIntervalMs)
 }
 
+func Write(ms *xmain.State, path string, out []byte) error {
+	err := ms.AtomicWritePath(path, out)
+	if err == nil {
+		return nil
+	}
+	ms.Log.Debug.Printf("atomic write failed: %s, trying non-atomic write", err.Error())
+	return ms.WritePath(path, out)
+}
+
 func init() {
 	log.Init()
 }
diff --git a/go.mod b/go.mod
index 040fd6c39..1dce72a30 100644
--- a/go.mod
+++ b/go.mod
@@ -29,7 +29,7 @@ require (
 	golang.org/x/xerrors v0.0.0-20240903120638-7835f813f4da
 	gonum.org/v1/plot v0.14.0
 	nhooyr.io/websocket v1.8.17
-	oss.terrastruct.com/util-go v0.0.0-20241001213509-2c8848a930fb
+	oss.terrastruct.com/util-go v0.0.0-20241005222610-44c011a04896
 )
 
 require (
diff --git a/go.sum b/go.sum
index f94228b1d..ccffe8f68 100644
--- a/go.sum
+++ b/go.sum
@@ -205,7 +205,7 @@ gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 nhooyr.io/websocket v1.8.17 h1:KEVeLJkUywCKVsnLIDlD/5gtayKp8VoCkksHCGGfT9Y=
 nhooyr.io/websocket v1.8.17/go.mod h1:rN9OFWIUwuxg4fR5tELlYC04bXYowCP9GX47ivo2l+c=
-oss.terrastruct.com/util-go v0.0.0-20241001213509-2c8848a930fb h1:3bvpnAM5gbaqmQYi1kWzNyfEH8p0UM4uCwAWV+/Ph7k=
-oss.terrastruct.com/util-go v0.0.0-20241001213509-2c8848a930fb/go.mod h1:eMWv0sOtD9T2RUl90DLWfuShZCYp4NrsqNpI8eqO6U4=
+oss.terrastruct.com/util-go v0.0.0-20241005222610-44c011a04896 h1:g752s1ECv9FD8GunFOZRGWzjeR0cr/TZdSsjAnFEmL8=
+oss.terrastruct.com/util-go v0.0.0-20241005222610-44c011a04896/go.mod h1:eMWv0sOtD9T2RUl90DLWfuShZCYp4NrsqNpI8eqO6U4=
 rsc.io/pdf v0.1.1 h1:k1MczvYDUvJBe93bYd7wrZLLUEcLZAuF824/I4e5Xr4=
 rsc.io/pdf v0.1.1/go.mod h1:n8OzWcQ6Sp37PL01nO98y4iUCRdTGarVfzxY20ICaU4=

From 1ba5ff07b9041646678f20d0e94dd16d879869fe Mon Sep 17 00:00:00 2001
From: Alexander Wang <alex@terrastruct.com>
Date: Sat, 5 Oct 2024 16:34:53 -0600
Subject: [PATCH 2/2] next

---
 ci/release/changelogs/next.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/ci/release/changelogs/next.md b/ci/release/changelogs/next.md
index df8527fd0..8e21b3c66 100644
--- a/ci/release/changelogs/next.md
+++ b/ci/release/changelogs/next.md
@@ -3,6 +3,7 @@
 #### Improvements 🧹
 
 - Lib: removes a dependency on external slog that was causing troubles with installation [#2137](https://github.com/terrastruct/d2/pull/2137)
+- CLI: attempts writing to path atomically, falling back to non-atomic if failed [#2141](https://github.com/terrastruct/d2/pull/2141)
 
 #### Bugfixes ⛑️