feat(record)!: use default commit message for --stash

But only when no message is explicitly supplied.

This is a breaking change. Previously, the user would be prompted for a message
if none was supplied.

Author: claytonrcarter

git-branchless-record/src/lib.rs

@@ -31,9 +31,9 @@ use lib::core::rewrite::{
     RepoResource,
 };
 use lib::git::{
-    process_diff_for_record, update_index, CategorizedReferenceName, FileMode, GitRunInfo,
-    MaybeZeroOid, NonZeroOid, Repo, ResolvedReferenceInfo, Stage, UpdateIndexCommand,
-    WorkingCopyChangesType, WorkingCopySnapshot,
+    process_diff_for_record, summarize_diff_for_temporary_commit, update_index,
+    CategorizedReferenceName, FileMode, GitRunInfo, MaybeZeroOid, NonZeroOid, Repo,
+    ResolvedReferenceInfo, Stage, UpdateIndexCommand, WorkingCopyChangesType, WorkingCopySnapshot,
 };
 use lib::try_exit_code;
 use lib::util::{ExitCode, EyreExitOr};
@@ -158,6 +158,12 @@ fn record(
             )?);
         }
     } else {
+        let messages = if messages.is_empty() && stash {
+            get_default_stash_message(&repo, effects, &snapshot, &working_copy_changes_type)
+                .map(|message| vec![message])?
+        } else {
+            messages
+        };
         let args = {
             let mut args = vec!["commit"];
             args.extend(messages.iter().flat_map(|message| ["--message", message]));
@@ -568,3 +574,42 @@ To proceed anyways, run: git move -f -s 'siblings(.)",
         ExecuteRebasePlanResult::Failed { exit_code } => Ok(Err(exit_code)),
     }
 }
+
+#[instrument]
+fn get_default_stash_message(
+    repo: &Repo,
+    effects: &Effects,
+    snapshot: &WorkingCopySnapshot,
+    working_copy_changes_type: &WorkingCopyChangesType,
+) -> eyre::Result<String> {
+    let (old_tree, new_tree) = match working_copy_changes_type {
+        WorkingCopyChangesType::Unstaged => {
+            let old_tree = snapshot.commit_stage0.get_tree()?;
+            let new_tree = snapshot.commit_unstaged.get_tree()?;
+            (Some(old_tree), new_tree)
+        }
+        WorkingCopyChangesType::Staged => {
+            let old_tree = match snapshot.head_commit {
+                None => None,
+                Some(ref commit) => Some(commit.get_tree()?),
+            };
+            let new_tree = snapshot.commit_stage0.get_tree()?;
+            (old_tree, new_tree)
+        }
+        WorkingCopyChangesType::None | WorkingCopyChangesType::Conflicts => {
+            unreachable!("already handled via early exit")
+        }
+    };
+
+    let diff = repo.get_diff_between_trees(
+        effects,
+        old_tree.as_ref(),
+        &new_tree,
+        0, // we don't care about the context here
+    )?;
+
+    Ok(format!(
+        "stash: {}",
+        summarize_diff_for_temporary_commit(&diff)?
+    ))
+}

git-branchless-record/tests/test_record.rs

@@ -342,6 +342,42 @@ fn test_record_stash() -> eyre::Result<()> {
     Ok(())
 }
 
+#[test]
+fn test_record_stash_default_message() -> eyre::Result<()> {
+    let git = make_git()?;
+
+    if !git.supports_reference_transactions()? {
+        return Ok(());
+    }
+    git.init_repo()?;
+
+    git.commit_file("test1", 1)?;
+
+    {
+        git.write_file_txt("test1", "new test1 contents\n")?;
+
+        let (stdout, _stderr) = git.branchless("record", &["--stash"])?;
+        insta::assert_snapshot!(stdout, @r###"
+        [master fd2ffa4] stash: test1.txt (+1/-1)
+         1 file changed, 1 insertion(+), 1 deletion(-)
+        branchless: running command: <git-executable> branch -f master 62fc20d2a290daea0d52bdc2ed2ad4be6491010e
+        branchless: running command: <git-executable> checkout master
+        "###);
+    }
+
+    {
+        let stdout = git.smartlog()?;
+        insta::assert_snapshot!(stdout, @r###"
+        :
+        @ 62fc20d (> master) create test1.txt
+        |
+        o fd2ffa4 stash: test1.txt (+1/-1)
+        "###);
+    }
+
+    Ok(())
+}
+
 #[test]
 fn test_record_create_branch() -> eyre::Result<()> {
     let git = make_git()?;