Add merge commit (#53)

* Add merge commit

* address review comments

* small fix

Author: SandrineP

src/subcommand/merge_subcommand.cpp

@@ -2,14 +2,17 @@
 #include <git2/types.h>
 
 #include "merge_subcommand.hpp"
-// #include "../wrapper/repository_wrapper.hpp"
+#include <iostream>
 
 
 merge_subcommand::merge_subcommand(const libgit2_object&, CLI::App& app)
 {
     auto *sub = app.add_subcommand("merge", "Join two or more development histories together");
 
     sub->add_option("<branch>", m_branches_to_merge, "Branch(es) to merge");
+    // sub->add_flag("--no-ff", m_no_ff, "");
+    // sub->add_flag("--commit", m_commit, "Perform the merge and commit the result. This option can be used to override --no-commit.");
+    sub->add_flag("--no-commit", m_no_commit, "With --no-commit perform the merge and stop just before creating a merge commit, to give the user a chance to inspect and further tweak the merge result before committing. \nNote that fast-forward updates do not create a merge commit and therefore there is no way to stop those merges with --no-commit. Thus, if you want to ensure your branch is not changed or updated by the merge command, use --no-ff with --no-commit.");
 
     sub->callback([this]() { this->run(); });
 }
@@ -54,6 +57,42 @@ void perform_fastforward(repository_wrapper& repo, const git_oid target_oid, int
     target_ref.write_new_ref(target_oid);
 }
 
+void merge_subcommand::create_merge_commit(
+    repository_wrapper& repo,
+    const index_wrapper& index,
+    const annotated_commit_list_wrapper& commits_to_merge,
+    size_t num_commits_to_merge)
+{
+    auto head_ref = repo.head();
+    auto merge_ref = repo.find_reference_dwim(m_branches_to_merge.front());
+    auto merge_commit = repo.resolve_local_ref(m_branches_to_merge.front()).value();
+
+    std::vector<commit_wrapper> parents_list;
+    parents_list.reserve(num_commits_to_merge + 1);
+    parents_list.push_back(std::move(head_ref.peel<commit_wrapper>()));
+    for (size_t i=0; i<num_commits_to_merge; ++i)
+    {
+        parents_list.push_back(repo.find_commit(commits_to_merge[i].oid()));
+    }
+    auto parents = commit_list_wrapper(std::move(parents_list));
+
+    auto author_committer_sign = signature_wrapper::get_default_signature_from_env(repo);
+    std::string author_name;
+    author_name = author_committer_sign.first.name();
+    std::string author_email;
+    author_email = author_committer_sign.first.email();
+    auto author_committer_sign_now = signature_wrapper::signature_now(author_name, author_email, author_name, author_email);
+
+    // TODO: add a prompt to edit the merge message
+    std::string msg_target = merge_ref ? merge_ref->short_name() : git_oid_tostr_s(&(merge_commit.oid()));
+	std::string msg = merge_ref ? "Merge branch " : "Merge commit ";
+	msg.append(msg_target);
+
+	repo.create_commit(author_committer_sign_now, msg, std::optional<commit_list_wrapper>(std::move(parents)));
+
+	repo.state_cleanup();
+}
+
 void merge_subcommand::run()
 {
     auto directory = get_current_git_path();
@@ -78,6 +117,7 @@ void merge_subcommand::run()
     if (analysis & GIT_MERGE_ANALYSIS_UP_TO_DATE)
     {
         std::cout << "Already up-to-date" << std::endl;
+        return;
     }
     else if (analysis & GIT_MERGE_ANALYSIS_UNBORN ||
              (analysis & GIT_MERGE_ANALYSIS_FASTFORWARD &&
@@ -97,4 +137,39 @@ void merge_subcommand::run()
         assert(num_commits_to_merge == 1);
         perform_fastforward(repo, target_oid, (analysis & GIT_MERGE_ANALYSIS_UNBORN));
     }
+    else if (analysis & GIT_MERGE_ANALYSIS_NORMAL)
+    {
+        git_merge_options merge_opts = GIT_MERGE_OPTIONS_INIT;
+		git_checkout_options checkout_opts = GIT_CHECKOUT_OPTIONS_INIT;
+
+		merge_opts.flags = 0;
+		merge_opts.file_flags = GIT_MERGE_FILE_STYLE_DIFF3;
+
+		checkout_opts.checkout_strategy = GIT_CHECKOUT_FORCE|GIT_CHECKOUT_ALLOW_CONFLICTS;
+
+		if (preference & GIT_MERGE_PREFERENCE_FASTFORWARD_ONLY)
+		{
+			std::cout << "Fast-forward is preferred, but only a merge is possible\n" << std::endl;
+		}
+
+		throw_if_error(git_merge(repo,
+		                         (const git_annotated_commit**)c_commits_to_merge,
+								 num_commits_to_merge,
+	                             &merge_opts,
+								 &checkout_opts));
+    }
+
+    index_wrapper index = repo.make_index();
+
+    if (git_index_has_conflicts(index))
+    {
+        std::cout << "Conflict. To be implemented" << std::endl;
+        /* Handle conflicts */
+		// output_conflicts(index);
+	}
+	else if (!m_no_commit)
+	{
+		create_merge_commit(repo, index, commits_to_merge, num_commits_to_merge);
+		printf("Merge made\n");
+	}
 }

src/subcommand/merge_subcommand.hpp

@@ -15,6 +15,14 @@ class merge_subcommand
 private:
 
     annotated_commit_list_wrapper resolve_heads(const repository_wrapper& repo);
+    void create_merge_commit(
+        repository_wrapper& repo,
+        const index_wrapper& index,
+        const annotated_commit_list_wrapper& commits_to_merge,
+        size_t num_commits_to_merge);
 
     std::vector<std::string> m_branches_to_merge;
+    // bool m_no_ff = false;
+    // bool m_commit = false;
+    bool m_no_commit = false;
 };

src/wrapper/repository_wrapper.cpp

@@ -2,6 +2,7 @@
 #include "../wrapper/index_wrapper.hpp"
 #include "../wrapper/object_wrapper.hpp"
 #include "../wrapper/commit_wrapper.hpp"
+#include <git2/repository.h>
 #include "../wrapper/repository_wrapper.hpp"
 
 repository_wrapper::~repository_wrapper()
@@ -36,6 +37,11 @@ git_repository_state_t repository_wrapper::state() const
     return git_repository_state_t(git_repository_state(*this));
 }
 
+void repository_wrapper::state_cleanup()
+{
+    throw_if_error(git_repository_state_cleanup(*this));
+}
+
 // References
 
 reference_wrapper repository_wrapper::head() const

src/wrapper/repository_wrapper.hpp

@@ -30,6 +30,7 @@ class repository_wrapper : public wrapper_base<git_repository>
     static repository_wrapper clone(std::string_view url, std::string_view path, const git_clone_options& opts);
 
     git_repository_state_t state() const;
+    void state_cleanup();
 
     // References
     reference_wrapper head() const;

src/wrapper/wrapper_base.hpp

@@ -71,11 +71,14 @@ class list_wrapper : public wrapper_base<typename T::resource_type*>
         return m_list.size();
     }
 
-    T front()
+    const T& operator[](size_t pos) const
     {
-        // TODO: rework wrapper so they can have references
-        // on libgit2 object without taking ownership
-        return T(std::move(m_list.front()));
+        return m_list[pos];
+    }
+
+    const T& front() const
+    {
+        return m_list.front();
     }
 
 private:

test/test_merge.py

@@ -44,3 +44,71 @@ def test_merge_fast_forward(xtl_clone, git_config, git2cpp_path, tmp_path, monke
     assert "Author:	Jane Doe" in p_log.stdout
     # assert "Commit:	John Doe" in p_log.stdout
     assert (xtl_path / "mook_file.txt").exists()
+
+    merge_cmd_2 = [git2cpp_path, "merge", "foregone"]
+    p_merge_2 = subprocess.run(
+        merge_cmd_2, capture_output=True, cwd=xtl_path, text=True
+    )
+    assert p_merge_2.returncode == 0
+    assert p_merge_2.stdout == "Already up-to-date\n"
+
+
+def test_merge(xtl_clone, git_config, git2cpp_path, tmp_path, monkeypatch):
+    assert (tmp_path / "xtl").exists()
+    xtl_path = tmp_path / "xtl"
+
+    checkout_cmd = [git2cpp_path, "checkout", "-b", "foregone"]
+    p_checkout = subprocess.run(
+        checkout_cmd, capture_output=True, cwd=xtl_path, text=True
+    )
+    assert p_checkout.returncode == 0
+
+    p = xtl_path / "mook_file.txt"
+    p.write_text("blablabla")
+
+    add_cmd = [git2cpp_path, "add", "mook_file.txt"]
+    p_add = subprocess.run(add_cmd, capture_output=True, cwd=xtl_path, text=True)
+    assert p_add.returncode == 0
+
+    commit_cmd = [git2cpp_path, "commit", "-m", "test commit foregone"]
+    p_commit = subprocess.run(commit_cmd, capture_output=True, cwd=xtl_path, text=True)
+    assert p_commit.returncode == 0
+
+    checkout_cmd_2 = [git2cpp_path, "checkout", "master"]
+    p_checkout_2 = subprocess.run(
+        checkout_cmd_2, capture_output=True, cwd=xtl_path, text=True
+    )
+    assert p_checkout_2.returncode == 0
+
+    p = xtl_path / "mook_file_2.txt"
+    p.write_text("BLABLABLA")
+
+    add_cmd_2 = [git2cpp_path, "add", "mook_file_2.txt"]
+    p_add_2 = subprocess.run(add_cmd_2, capture_output=True, cwd=xtl_path, text=True)
+    assert p_add_2.returncode == 0
+
+    commit_cmd_2 = [git2cpp_path, "commit", "-m", "test commit master"]
+    p_commit_2 = subprocess.run(
+        commit_cmd_2, capture_output=True, cwd=xtl_path, text=True
+    )
+    assert p_commit_2.returncode == 0
+
+    merge_cmd = [git2cpp_path, "merge", "foregone"]
+    p_merge = subprocess.run(merge_cmd, capture_output=True, cwd=xtl_path, text=True)
+    assert p_merge.returncode == 0
+
+    log_cmd = [git2cpp_path, "log", "--format=full", "--max-count", "2"]
+    p_log = subprocess.run(log_cmd, capture_output=True, cwd=xtl_path, text=True)
+    assert p_log.returncode == 0
+    assert "Author:	Jane Doe" in p_log.stdout
+    # assert "Commit:	John Doe" in p_log.stdout
+    assert "Johan" not in p_log.stdout
+    assert (xtl_path / "mook_file.txt").exists()
+    assert (xtl_path / "mook_file.txt").exists()
+
+    merge_cmd_2 = [git2cpp_path, "merge", "foregone"]
+    p_merge_2 = subprocess.run(
+        merge_cmd_2, capture_output=True, cwd=xtl_path, text=True
+    )
+    assert p_merge_2.returncode == 0
+    assert p_merge_2.stdout == "Already up-to-date\n"