[PATCH proxmox 01/15] sys: fs: don't replace file extension make_tmp_file

[Lukas Wagner <l.wagner@proxmox.com>]

Rather than creating the template path used by mkostemp by replacing the
existing file extension, use `add_extension` to append to any existing
one.

We often provide the path of some original file that is later to be
replaced by the temporary one, and therefore having the full original
filename intact is a benefit for debugability in case there are
leftover temporary files.

For instance, the task archive in PDM uses the following file name
schema: `archive.{timestamp}[.zst]`. Archive files are atomically
replaced by using make_tmp_file and rename, however due to using
`set_extension` before, the `{timestamp}[.zst]` part would be lost.

Signed-off-by: Lukas Wagner <l.wagner@proxmox.com>
---
 proxmox-sys/src/fs/file.rs | 34 +++++++++++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/proxmox-sys/src/fs/file.rs b/proxmox-sys/src/fs/file.rs
index f0939381..3336156b 100644
--- a/proxmox-sys/src/fs/file.rs
+++ b/proxmox-sys/src/fs/file.rs
@@ -149,7 +149,7 @@ pub fn make_tmp_file<P: AsRef<Path>>(
 
     // use mkstemp here, because it works with different processes, threads, even tokio tasks
     let mut template = path.to_owned();
-    template.set_extension("tmp_XXXXXX");
+    template.add_extension("tmp_XXXXXX");
     let (mut file, tmp_path) = match mkostemp(&template, OFlag::O_CLOEXEC) {
         Ok((fd, path)) => (unsafe { File::from_raw_fd(fd) }, path),
         Err(err) => bail!("mkstemp {:?} failed: {}", template, err),
@@ -466,3 +466,35 @@ pub fn file_get_non_comment_lines<P: AsRef<Path>>(
         Err(err) => Some(Err(err)),
     }))
 }
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn make_tmp_file_does_not_replace_extension() {
+        let (_, path) = make_tmp_file("/tmp/proxmox-sys-test.json", CreateOptions::new()).unwrap();
+
+        assert!(
+            &path
+                .file_name()
+                .unwrap()
+                .to_string_lossy()
+                .contains("proxmox-sys-test.json")
+        );
+
+        let (_, path) = make_tmp_file(
+            "/tmp/proxmox-sys-test.archive.1000.zst",
+            CreateOptions::new(),
+        )
+        .unwrap();
+
+        assert!(
+            &path
+                .file_name()
+                .unwrap()
+                .to_string_lossy()
+                .contains("archive.1000.zst")
+        );
+    }
+}
-- 
2.47.3