Add commit_raw and commit_as_raw methods for creating commits without reference updates

gix/src/commit.rs

@@ -6,7 +6,7 @@ use std::convert::Infallible;
 /// An empty array of a type usable with the `gix::easy` API to help declaring no parents should be used
 pub const NO_PARENT_IDS: [gix_hash::ObjectId; 0] = [];
 
-/// The error returned by [`commit(…)`][crate::Repository::commit()].
+/// The error returned by [`commit(…)`](crate::Repository::commit()).
 #[derive(Debug, thiserror::Error)]
 #[allow(missing_docs)]
 pub enum Error {

gix/src/lib.rs

@@ -86,7 +86,7 @@
     doc = ::document_features::document_features!()
 )]
 #![cfg_attr(all(doc, feature = "document-features"), feature(doc_cfg, doc_auto_cfg))]
-#![deny(missing_docs, rust_2018_idioms, unsafe_code)]
+#![deny(missing_docs, unsafe_code)]
 #![allow(clippy::result_large_err)]
 
 // Re-exports to make this a potential one-stop shop crate avoiding people from having to reference various crates themselves.

gix/src/repository/mod.rs

@@ -63,6 +63,36 @@ mod submodule;
 mod thread_safe;
 mod worktree;
 
+///
+mod new_commit {
+    /// The error returned by [`new_commit(…)`](crate::Repository::new_commit()).
+    #[derive(Debug, thiserror::Error)]
+    #[allow(missing_docs)]
+    pub enum Error {
+        #[error(transparent)]
+        ParseTime(#[from] crate::config::time::Error),
+        #[error("Committer identity is not configured")]
+        CommitterMissing,
+        #[error("Author identity is not configured")]
+        AuthorMissing,
+        #[error(transparent)]
+        NewCommitAs(#[from] crate::repository::new_commit_as::Error),
+    }
+}
+
+///
+mod new_commit_as {
+    /// The error returned by [`new_commit_as(…)`](crate::Repository::new_commit_as()).
+    #[derive(Debug, thiserror::Error)]
+    #[allow(missing_docs)]
+    pub enum Error {
+        #[error(transparent)]
+        WriteObject(#[from] crate::object::write::Error),
+        #[error(transparent)]
+        FindCommit(#[from] crate::object::find::existing::Error),
+    }
+}
+
 ///
 #[cfg(feature = "blame")]
 pub mod blame_file {

gix/src/repository/object.rs

@@ -10,6 +10,7 @@ use gix_ref::{
 };
 use smallvec::SmallVec;
 
+use crate::repository::{new_commit, new_commit_as};
 use crate::{commit, ext::ObjectIdExt, object, tag, Blob, Commit, Id, Object, Reference, Tag, Tree};
 
 /// Tree editing
@@ -264,7 +265,7 @@ impl crate::Repository {
     /// Create a tag reference named `name` (without `refs/tags/` prefix) pointing to a newly created tag object
     /// which in turn points to `target` and return the newly created reference.
     ///
-    /// It will be created with `constraint` which is most commonly to [only create it][PreviousValue::MustNotExist]
+    /// It will be created with `constraint` which is most commonly to [only create it](PreviousValue::MustNotExist)
     /// or to [force overwriting a possibly existing tag](PreviousValue::Any).
     pub fn tag(
         &self,
@@ -406,6 +407,49 @@ impl crate::Repository {
         self.commit_as(committer, author, reference, message, tree, parents)
     }
 
+    /// Create a new commit object with `message` referring to `tree` with `parents`, and write it to the object database.
+    /// Do not, however, update any references.
+    ///
+    /// The commit is created without message encoding field, which can be assumed to be UTF-8.
+    /// `author` and `committer` fields are pre-set from the configuration, which can be altered
+    /// [temporarily](crate::Repository::config_snapshot_mut()) before the call if required.
+    pub fn new_commit(
+        &self,
+        message: impl AsRef<str>,
+        tree: impl Into<ObjectId>,
+        parents: impl IntoIterator<Item = impl Into<ObjectId>>,
+    ) -> Result<Commit<'_>, new_commit::Error> {
+        let author = self.author().ok_or(new_commit::Error::AuthorMissing)??;
+        let committer = self.committer().ok_or(new_commit::Error::CommitterMissing)??;
+        Ok(self.new_commit_as(committer, author, message, tree, parents)?)
+    }
+
+    /// Create a nwe commit object with `message` referring to `tree` with `parents`, using the specified
+    /// `committer` and `author`, and write it to the object database. Do not, however, update any references.
+    ///
+    /// This forces setting the commit time and author time by hand. Note that typically, committer and author are the same.
+    /// The commit is created without message encoding field, which can be assumed to be UTF-8.
+    pub fn new_commit_as<'a, 'c>(
+        &self,
+        committer: impl Into<gix_actor::SignatureRef<'c>>,
+        author: impl Into<gix_actor::SignatureRef<'a>>,
+        message: impl AsRef<str>,
+        tree: impl Into<ObjectId>,
+        parents: impl IntoIterator<Item = impl Into<ObjectId>>,
+    ) -> Result<Commit<'_>, new_commit_as::Error> {
+        let commit = gix_object::Commit {
+            message: message.as_ref().into(),
+            tree: tree.into(),
+            author: author.into().into(),
+            committer: committer.into().into(),
+            encoding: None,
+            parents: parents.into_iter().map(Into::into).collect(),
+            extra_headers: Default::default(),
+        };
+        let id = self.write_object(commit)?;
+        Ok(id.object()?.into_commit())
+    }
+
     /// Return an empty tree object, suitable for [getting changes](Tree::changes()).
     ///
     /// Note that the returned object is special and doesn't necessarily physically exist in the object database.

gix/tests/gix/repository/object.rs

@@ -1,8 +1,9 @@
+use gix_date::parse::TimeBuf;
 use gix_odb::Header;
 use gix_pack::Find;
 use gix_testtools::tempfile;
 
-use crate::util::named_subrepo_opts;
+use crate::util::{hex_to_id, named_subrepo_opts};
 
 mod object_database_impl {
     use gix_object::{Exists, Find, FindHeader};
@@ -786,6 +787,68 @@ mod commit {
     }
 }
 
+#[test]
+fn new_commit_as() -> crate::Result {
+    let repo = empty_bare_in_memory_repo()?;
+    let empty_tree = repo.empty_tree();
+    let committer = gix::actor::Signature {
+        name: "c".into(),
+        email: "c@example.com".into(),
+        time: gix_date::parse_header("1 +0030").unwrap(),
+    };
+    let author = gix::actor::Signature {
+        name: "a".into(),
+        email: "a@example.com".into(),
+        time: gix_date::parse_header("3 +0100").unwrap(),
+    };
+
+    let commit = repo.new_commit_as(
+        committer.to_ref(&mut TimeBuf::default()),
+        author.to_ref(&mut TimeBuf::default()),
+        "message",
+        empty_tree.id,
+        gix::commit::NO_PARENT_IDS,
+    )?;
+
+    assert_eq!(
+        commit.id,
+        hex_to_id("b51277f2b2ea77676dd6fa877b5eb5ba2f7094d9"),
+        "The commit-id is stable as the author/committer is controlled"
+    );
+
+    let commit = commit.decode()?;
+
+    let mut buf = TimeBuf::default();
+    assert_eq!(commit.committer, committer.to_ref(&mut buf));
+    assert_eq!(commit.author, author.to_ref(&mut buf));
+    assert_eq!(commit.message, "message");
+    assert_eq!(commit.tree(), empty_tree.id);
+    assert_eq!(commit.parents.len(), 0);
+
+    assert!(repo.head()?.is_unborn(), "The head-ref wasn't touched");
+    Ok(())
+}
+
+#[test]
+fn new_commit() -> crate::Result {
+    let mut repo = empty_bare_in_memory_repo()?;
+    let mut config = repo.config_snapshot_mut();
+    config.set_value(&gix::config::tree::User::NAME, "user")?;
+    config.set_value(&gix::config::tree::User::EMAIL, "user@example.com")?;
+    config.commit()?;
+
+    let empty_tree_id = repo.object_hash().empty_tree();
+    let commit = repo.new_commit("initial", empty_tree_id, gix::commit::NO_PARENT_IDS)?;
+    let commit = commit.decode()?;
+
+    assert_eq!(commit.message, "initial");
+    assert_eq!(commit.tree(), empty_tree_id);
+    assert_eq!(commit.parents.len(), 0);
+
+    assert!(repo.head()?.is_unborn(), "The head-ref wasn't touched");
+    Ok(())
+}
+
 fn empty_bare_in_memory_repo() -> crate::Result<gix::Repository> {
     Ok(named_subrepo_opts("make_basic_repo.sh", "bare.git", gix::open::Options::isolated())?.with_object_memory())
 }