gix_merge/commit/
function.rs

1use crate::blob::builtin_driver;
2use crate::commit::{Error, Options};
3use gix_object::FindExt;
4use std::borrow::Cow;
5
6/// Like [`tree()`](crate::tree()), but it takes only two commits, `our_commit` and `their_commit` to automatically
7/// compute the merge-bases among them.
8/// If there are multiple merge bases, these will be auto-merged into one, recursively, if
9/// [`allow_missing_merge_base`](Options::allow_missing_merge_base) is `true`.
10///
11/// `labels` are names where [`current`](crate::blob::builtin_driver::text::Labels::current) is a name for `our_commit`
12/// and [`other`](crate::blob::builtin_driver::text::Labels::other) is a name for `their_commit`.
13/// If [`ancestor`](crate::blob::builtin_driver::text::Labels::ancestor) is unset, it will be set by us based on the
14/// merge-bases of `our_commit` and `their_commit`.
15///
16/// The `graph` is used to find the merge-base between `our_commit` and `their_commit`, and can also act as cache
17/// to speed up subsequent merge-base queries.
18///
19/// Use `abbreviate_hash(id)` to shorten the given `id` according to standard git shortening rules. It's used in case
20/// the ancestor-label isn't explicitly set so that the merge base label becomes the shortened `id`.
21/// Note that it's a dyn closure only to make it possible to recursively call this function in case of multiple merge-bases.
22///
23/// `write_object` is used only if it's allowed to merge multiple merge-bases into one, and if there
24/// are multiple merge bases, and to write merged buffers as blobs.
25///
26/// ### Performance
27///
28/// Note that `objects` *should* have an object cache to greatly accelerate tree-retrieval.
29///
30/// ### Notes
31///
32/// When merging merge-bases recursively, the options are adjusted automatically to act like Git, i.e. merge binary
33/// blobs and resolve with *ours*, while resorting to using the base/ancestor in case of unresolvable conflicts.
34///
35/// ### Deviation
36///
37/// * It's known that certain conflicts around symbolic links can be auto-resolved. We don't have an option for this
38///   at all, yet, primarily as Git seems to not implement the *ours*/*theirs* choice in other places even though it
39///   reasonably could. So we leave it to the caller to continue processing the returned tree at will.
40#[allow(clippy::too_many_arguments)]
41pub fn commit<'objects>(
42    our_commit: gix_hash::ObjectId,
43    their_commit: gix_hash::ObjectId,
44    labels: builtin_driver::text::Labels<'_>,
45    graph: &mut gix_revwalk::Graph<'_, '_, gix_revwalk::graph::Commit<gix_revision::merge_base::Flags>>,
46    diff_resource_cache: &mut gix_diff::blob::Platform,
47    blob_merge: &mut crate::blob::Platform,
48    objects: &'objects (impl gix_object::FindObjectOrHeader + gix_object::Write),
49    abbreviate_hash: &mut dyn FnMut(&gix_hash::oid) -> String,
50    options: Options,
51) -> Result<super::Outcome<'objects>, Error> {
52    let merge_bases = gix_revision::merge_base(our_commit, &[their_commit], graph)?;
53    let mut virtual_merge_bases = Vec::new();
54    let mut state = gix_diff::tree::State::default();
55    let mut commit_to_tree =
56        |commit_id: gix_hash::ObjectId| objects.find_commit(&commit_id, &mut state.buf1).map(|c| c.tree());
57
58    let (merge_base_tree_id, ancestor_name): (_, Cow<'_, str>) = match merge_bases.clone() {
59        Some(base_commit) if base_commit.len() == 1 => {
60            (commit_to_tree(base_commit[0])?, abbreviate_hash(&base_commit[0]).into())
61        }
62        Some(mut base_commits) => {
63            let virtual_base_tree = if options.use_first_merge_base {
64                let first = base_commits.first().expect("if Some() there is at least one.");
65                commit_to_tree(*first)?
66            } else {
67                let first = base_commits.pop().expect("at least two");
68                let second = base_commits.pop().expect("at least one left");
69                let out = crate::commit::virtual_merge_base(
70                    first,
71                    second,
72                    base_commits,
73                    graph,
74                    diff_resource_cache,
75                    blob_merge,
76                    objects,
77                    abbreviate_hash,
78                    options.tree_merge.clone(),
79                )?;
80                virtual_merge_bases = out.virtual_merge_bases;
81                out.tree_id
82            };
83            (virtual_base_tree, "merged common ancestors".into())
84        }
85        None => {
86            if options.allow_missing_merge_base {
87                (gix_hash::ObjectId::empty_tree(our_commit.kind()), "empty tree".into())
88            } else {
89                return Err(Error::NoMergeBase {
90                    our_commit_id: our_commit,
91                    their_commit_id: their_commit,
92                });
93            }
94        }
95    };
96
97    let mut labels = labels; // TODO(borrowchk): this re-assignment shouldn't be needed.
98    if labels.ancestor.is_none() {
99        labels.ancestor = Some(ancestor_name.as_ref().into());
100    }
101
102    let our_tree_id = objects.find_commit(&our_commit, &mut state.buf1)?.tree();
103    let their_tree_id = objects.find_commit(&their_commit, &mut state.buf1)?.tree();
104
105    let outcome = crate::tree(
106        &merge_base_tree_id,
107        &our_tree_id,
108        &their_tree_id,
109        labels,
110        objects,
111        |buf| objects.write_buf(gix_object::Kind::Blob, buf),
112        &mut state,
113        diff_resource_cache,
114        blob_merge,
115        options.tree_merge,
116    )?;
117
118    Ok(super::Outcome {
119        tree_merge: outcome,
120        merge_bases,
121        merge_base_tree_id,
122        virtual_merge_bases,
123    })
124}
gix_merge/commit/function.rs

gix_merge/commit/
function.rs
