From d6351282bc7abdd310402fae063d093184e99758 Mon Sep 17 00:00:00 2001
From: Johan Norberg <johnor@users.noreply.github.com>
Date: Wed, 12 Mar 2025 19:47:10 +0100
Subject: [PATCH 1/2] Show better message if an expected file is not found

---
 src/object.rs | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/src/object.rs b/src/object.rs
index 56ac8e8..8e49c66 100644
--- a/src/object.rs
+++ b/src/object.rs
@@ -197,6 +197,9 @@ impl Object {
     }
 
     pub fn from_file(path: &std::path::Path) -> Result<Object> {
+        if !path.exists() {
+            return Err(anyhow!("Expected file: {:?} does not exist", path));
+        }
         let data = std::fs::read(path).context("Could not read from file")?;
         let mut z = ZlibDecoder::new(&data[..]);
         let mut s: Vec<u8> = vec![];
@@ -286,6 +289,8 @@ pub fn hash(s: &[u8]) -> String {
 
 #[cfg(test)]
 mod tests {
+    use tempfile::tempdir;
+
     use crate::object::File;
 
     use super::Blob;
@@ -411,6 +416,28 @@ parent";
         assert_eq!(err, "Incorrect header length");
     }
 
+    #[test]
+    fn test_from_file_nonexisting_file() {
+        let result = Object::from_file(std::path::Path::new("/nonexisting/file"));
+        assert!(result.is_err());
+        assert_eq!(
+            result.unwrap_err().to_string(),
+            "Expected file: \"/nonexisting/file\" does not exist"
+        );
+    }
+
+    #[test]
+    fn test_from_file_with_invalid_data() {
+        let dir = tempdir().unwrap();
+        let file_path = dir.path().join("invalid_object");
+
+        std::fs::write(&file_path, "not a valid git object").unwrap();
+
+        let result = Object::from_file(&file_path);
+        assert!(result.is_err());
+        assert_eq!(result.unwrap_err().to_string(), "corrupt deflate stream");
+    }
+
     #[test]
     fn test_blob_hash_is_correct() {
         // From https://git-scm.com/book/sv/v2/Git-Internals-Git-Objects

From 1d0be180b221d2358c5961dbb43a35b06fd82579 Mon Sep 17 00:00:00 2001
From: Johan Norberg <johnor@users.noreply.github.com>
Date: Wed, 12 Mar 2025 19:47:59 +0100
Subject: [PATCH 2/2] Handle HEAD as rev

* This means things like "cat-file HEAD" and "log HEAD" works.
---
 src/lib.rs        |  8 +++-----
 src/object.rs     |  4 ++++
 tests/git_test.rs | 18 +++---------------
 3 files changed, 10 insertions(+), 20 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index 68d1280..214e55c 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -107,11 +107,9 @@ pub fn log(repo: &Repo, object_rev: &str, stdout: &mut dyn io::Write) -> Result<
             Object::Commit(commit) => {
                 let commiter = commit.committer;
                 let first_line = commit.message.lines().next().unwrap_or("");
-                writeln!(
-                    stdout,
-                    "{hash} - {first_line} - \"{commiter}\"",
-                    hash = &this_rev[0..6]
-                )?;
+                // TODO: resolve all refs to their full hash.
+                // Now this_rev could be for example a branch name.
+                writeln!(stdout, "{this_rev:.6} - {first_line} - \"{commiter}\"",)?;
                 if commit.parent.is_empty() {
                     return Ok(());
                 } else {
diff --git a/src/object.rs b/src/object.rs
index 8e49c66..7b519a0 100644
--- a/src/object.rs
+++ b/src/object.rs
@@ -227,6 +227,10 @@ impl Object {
     pub fn from_rev(repo: &Repo, rev: &str) -> Result<Object> {
         let mut candidates: Vec<String> = vec![];
 
+        if rev == "HEAD" {
+            return Object::from_hash(repo, &refs::find_ref("HEAD", repo)?);
+        }
+
         // Check if this is a hash
         if rev.len() >= 4 {
             let (short_hash, long_hash) = rev.split_at(2);
diff --git a/tests/git_test.rs b/tests/git_test.rs
index b9769e9..6825199 100644
--- a/tests/git_test.rs
+++ b/tests/git_test.rs
@@ -168,25 +168,12 @@ mod tests {
     use super::*;
     use rstest::rstest;
 
-    #[rstest]
-    fn test_cat_file(test_repo: tempfile::TempDir) {
-        let repo = Repo::new(test_repo.path());
-        let mut stdout = Vec::new();
-
-        good_git::cat_file(
-            &repo,
-            "d670460b4b4aece5915caf5c68d12f560a9fe3e4",
-            &mut stdout,
-        )
-        .unwrap();
-        assert_eq!(stdout, b"test content\n\n");
-    }
-
     #[rstest]
     #[case("d670", b"test content\n\n".to_vec())]
     #[case("d67046", b"test content\n\n".to_vec())]
+    #[case("d670460b4b4aece5915caf5c68d12f560a9fe3e4", b"test content\n\n".to_vec())]
     #[case("1234567890", b"more content\nfrom a good client\n".to_vec())]
-    fn test_cat_file_short_hash(
+    fn test_cat_file(
         test_repo: tempfile::TempDir,
         #[case] input: String,
         #[case] expected: Vec<u8>,
@@ -246,6 +233,7 @@ from a good client
     #[rstest]
     #[case("aaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbb")]
     #[case("main")] // Points to the same commit
+    #[case("HEAD")]
     fn test_cat_file_commit(test_repo: tempfile::TempDir, #[case] reference: String) {
         let repo = Repo::new(test_repo.path());
         let mut stdout = Vec::new();