From b00222ecf6275d73535093e31fc69e51e9203e18 Mon Sep 17 00:00:00 2001
From: Jille Timmermans <jille@hexon.nl>
Date: Fri, 2 Feb 2024 11:41:42 +0100
Subject: [PATCH] Add WithSyncDirectory to optionally fsync the directory after
 the rename

---
 option.go   |  9 +++++++++
 tempfile.go | 19 ++++++++++++++++++-
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/option.go b/option.go
index a86906f..671d49c 100644
--- a/option.go
+++ b/option.go
@@ -86,3 +86,12 @@ func WithReplaceOnClose() Option {
 		c.renameOnClose = true
 	})
 }
+
+// WithSyncDirectory configures renameio to fsync the directory after renaming
+// the file. If that succeeds it's guaranteed the file will be in the new state
+// even after a crash.
+func WithSyncDirectory() Option {
+	return optionFunc(func(c *config) {
+		c.syncDirectory = true
+	})
+}
diff --git a/tempfile.go b/tempfile.go
index 98114e5..451dafc 100644
--- a/tempfile.go
+++ b/tempfile.go
@@ -118,6 +118,7 @@ type PendingFile struct {
 	done           bool
 	closed         bool
 	replaceOnClose bool
+	syncDirectory  bool
 }
 
 // Cleanup is a no-op if CloseAtomicallyReplace succeeded, and otherwise closes
@@ -167,6 +168,16 @@ func (t *PendingFile) CloseAtomicallyReplace() error {
 		return err
 	}
 	t.done = true
+	if t.syncDirectory {
+		dh, err := os.OpenFile(filepath.Dir(t.path), os.O_WRONLY, 0)
+		if err != nil {
+			return err
+		}
+		defer dh.Close()
+		if err := dh.Sync(); err != nil {
+			return err
+		}
+	}
 	return nil
 }
 
@@ -200,6 +211,7 @@ type config struct {
 	ignoreUmask     bool
 	chmod           *os.FileMode
 	renameOnClose   bool
+	syncDirectory   bool
 }
 
 // NewPendingFile creates a temporary file destined to atomically creating or
@@ -255,7 +267,12 @@ func NewPendingFile(path string, opts ...Option) (*PendingFile, error) {
 		}
 	}
 
-	return &PendingFile{File: f, path: cfg.path, replaceOnClose: cfg.renameOnClose}, nil
+	return &PendingFile{
+		File:           f,
+		path:           cfg.path,
+		replaceOnClose: cfg.renameOnClose,
+		syncDirectory:  cfg.syncDirectory,
+	}, nil
 }
 
 // Symlink wraps os.Symlink, replacing an existing symlink with the same name