From a84ae0950cb50549cde6cf9039eaf5668d2ced46 Mon Sep 17 00:00:00 2001
From: Stephan Dilly <dilly.stephan@gmail.com>
Date: Fri, 10 Jul 2020 11:25:00 +0200
Subject: [PATCH] `add_to_ignore` failed on files without a newline at EOF
 (closes #191)

---
 CHANGELOG.md                |   1 +
 asyncgit/src/sync/ignore.rs | 106 +++++++++++++++++++++++++++++++++++-
 2 files changed, 105 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 05c2aaee..5dee7866 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - removed unmaintained dependency `spin` ([#172](https://github.com/extrawurst/gitui/issues/172))
 - opening relative paths in external editor may fail in subpaths ([#184](https://github.com/extrawurst/gitui/issues/184))
 - crashes in revlog with utf8 commit messages ([#188](https://github.com/extrawurst/gitui/issues/188))
+- `add_to_ignore` failed on files without a newline at EOF ([#191](https://github.com/extrawurst/gitui/issues/191))
 
 ## [0.8.1] - 2020-07-07
 
diff --git a/asyncgit/src/sync/ignore.rs b/asyncgit/src/sync/ignore.rs
index 38ce376b..c71ad462 100644
--- a/asyncgit/src/sync/ignore.rs
+++ b/asyncgit/src/sync/ignore.rs
@@ -1,7 +1,11 @@
 use super::utils::{repo, work_dir};
 use crate::error::Result;
 use scopetime::scope_time;
-use std::{fs::OpenOptions, io::Write};
+use std::{
+    fs::{File, OpenOptions},
+    io::{Read, Seek, SeekFrom, Write},
+    path::PathBuf,
+};
 
 static GITIGNORE: &str = ".gitignore";
 
@@ -16,12 +20,110 @@ pub fn add_to_ignore(
 
     let ignore_file = work_dir(&repo).join(GITIGNORE);
 
+    let optional_newline = ignore_file.exists()
+        && !file_ends_with_newline(&ignore_file)?;
+
     let mut file = OpenOptions::new()
         .append(true)
         .create(true)
         .open(ignore_file)?;
 
-    writeln!(file, "{}", path_to_ignore)?;
+    writeln!(
+        file,
+        "{}{}",
+        if optional_newline { "\n" } else { "" },
+        path_to_ignore
+    )?;
 
     Ok(())
 }
+
+fn file_ends_with_newline(file: &PathBuf) -> Result<bool> {
+    let mut file = File::open(file)?;
+    let size = file.metadata()?.len();
+
+    file.seek(SeekFrom::Start(size.saturating_sub(1)))?;
+    let mut last_char = String::with_capacity(1);
+    file.read_to_string(&mut last_char)?;
+
+    dbg!(&last_char);
+
+    Ok(last_char == "\n")
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::sync::tests::repo_init;
+    use io::BufRead;
+    use std::{fs::File, io, path::Path};
+
+    #[test]
+    fn test_empty() -> Result<()> {
+        let ignore_file_path = Path::new(".gitignore");
+        let file_path = Path::new("foo.txt");
+        let (_td, repo) = repo_init()?;
+        let root = repo.path().parent().unwrap();
+        let repo_path = root.as_os_str().to_str().unwrap();
+
+        File::create(&root.join(file_path))?.write_all(b"test")?;
+
+        assert_eq!(root.join(ignore_file_path).exists(), false);
+        add_to_ignore(repo_path, file_path.to_str().unwrap())?;
+        assert_eq!(root.join(ignore_file_path).exists(), true);
+
+        Ok(())
+    }
+
+    fn read_lines<P>(
+        filename: P,
+    ) -> io::Result<io::Lines<io::BufReader<File>>>
+    where
+        P: AsRef<Path>,
+    {
+        let file = File::open(filename)?;
+        Ok(io::BufReader::new(file).lines())
+    }
+
+    #[test]
+    fn test_append() -> Result<()> {
+        let ignore_file_path = Path::new(".gitignore");
+        let file_path = Path::new("foo.txt");
+        let (_td, repo) = repo_init()?;
+        let root = repo.path().parent().unwrap();
+        let repo_path = root.as_os_str().to_str().unwrap();
+
+        File::create(&root.join(file_path))?.write_all(b"test")?;
+        File::create(&root.join(ignore_file_path))?
+            .write_all(b"foo\n")?;
+
+        add_to_ignore(repo_path, file_path.to_str().unwrap())?;
+
+        let mut lines =
+            read_lines(&root.join(ignore_file_path)).unwrap();
+        assert_eq!(&lines.nth(1).unwrap().unwrap(), "foo.txt");
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_append_no_newline_at_end() -> Result<()> {
+        let ignore_file_path = Path::new(".gitignore");
+        let file_path = Path::new("foo.txt");
+        let (_td, repo) = repo_init()?;
+        let root = repo.path().parent().unwrap();
+        let repo_path = root.as_os_str().to_str().unwrap();
+
+        File::create(&root.join(file_path))?.write_all(b"test")?;
+        File::create(&root.join(ignore_file_path))?
+            .write_all(b"foo")?;
+
+        add_to_ignore(repo_path, file_path.to_str().unwrap())?;
+
+        let mut lines =
+            read_lines(&root.join(ignore_file_path)).unwrap();
+        assert_eq!(&lines.nth(1).unwrap().unwrap(), "foo.txt");
+
+        Ok(())
+    }
+}