From 072f5d9d7d7c314fcdc09eedfb4960fac772e81d Mon Sep 17 00:00:00 2001
From: Rijnard van Tonder <rvantonder@gmail.com>
Date: Thu, 29 Feb 2024 23:47:21 -0800
Subject: [PATCH] move lock: rewind when creating new lock file from copy
 (#16444)

## Description

When getting a lock file handle it's useful for it to be set to the beginning for reads rather than the caller needing to rewind it (or forgetting to and not seeing content when reading from the handle).

## Test Plan

Covered by existing test that exercises these functions together.

---
If your changes are not user-facing and do not break anything, you can
skip the following section. Otherwise, please briefly describe what has
changed under the Release Notes section.

### Type of Change (Check all that apply)

- [ ] protocol change
- [ ] user-visible impact
- [ ] breaking change for a client SDKs
- [ ] breaking change for FNs (FN binary must upgrade)
- [ ] breaking change for validators or node operators (must upgrade
binaries)
- [ ] breaking change for on-chain data layout
- [ ] necessitate either a data wipe or data migration

### Release notes
---
 crates/move-package/src/lib.rs           | 3 +--
 crates/move-package/src/lock_file/mod.rs | 3 ++-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/crates/move-package/src/lib.rs b/crates/move-package/src/lib.rs
index e9a993f2e5..6737c5d7ee 100644
--- a/crates/move-package/src/lib.rs
+++ b/crates/move-package/src/lib.rs
@@ -25,7 +25,7 @@ use serde::{Deserialize, Serialize};
 use source_package::{layout::SourcePackageLayout, parsed_manifest::DependencyKind};
 use std::{
     collections::BTreeMap,
-    io::{BufRead, Seek, SeekFrom, Write},
+    io::{BufRead, Write},
     path::{Path, PathBuf},
 };
 
@@ -277,7 +277,6 @@ impl BuildConfig {
         };
         let install_dir = self.install_dir.as_ref().unwrap_or(path).to_owned();
         let mut lock = LockFile::from(install_dir, lock_file)?;
-        lock.seek(SeekFrom::Start(0))?;
         update_compiler_toolchain(
             &mut lock,
             compiler_version,
diff --git a/crates/move-package/src/lock_file/mod.rs b/crates/move-package/src/lock_file/mod.rs
index b4a3113215..eca28477b9 100644
--- a/crates/move-package/src/lock_file/mod.rs
+++ b/crates/move-package/src/lock_file/mod.rs
@@ -3,7 +3,7 @@
 
 use std::{
     fs::{self, File},
-    io::Write,
+    io::{Seek, SeekFrom, Write},
     ops::{Deref, DerefMut},
     path::{Path, PathBuf},
 };
@@ -75,6 +75,7 @@ impl LockFile {
             .context("Creating lock file")?;
         let lock_string = std::fs::read_to_string(lock_file)?;
         lock.write_all(lock_string.as_bytes())?;
+        lock.seek(SeekFrom::Start(0))?;
 
         Ok(LockFile { file: lock })
     }