Merge pull request #2235 from jacquesg/cherry-pick

Add cherry pick support

AUTHORS

@@ -25,6 +25,7 @@ Florian Forster
 Holger Weiss
 Ingmar Vanhassel
 J. David Ibáñez
+Jacques Germishuys
 Jakob Pfender
 Jason Penny
 Jason R. McNeil

include/git2.h

@@ -14,6 +14,7 @@
 #include "git2/branch.h"
 #include "git2/buffer.h"
 #include "git2/checkout.h"
+#include "git2/cherrypick.h"
 #include "git2/clone.h"
 #include "git2/commit.h"
 #include "git2/common.h"

include/git2/cherrypick.h

@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_git_cherrypick_h__
+#define INCLUDE_git_cherrypick_h__
+
+#include "common.h"
+#include "types.h"
+#include "merge.h"
+
+/**
+ * @file git2/cherrypick.h
+ * @brief Git cherry-pick routines
+ * @defgroup git_cherrypick Git cherry-pick routines
+ * @ingroup Git
+ * @{
+ */
+GIT_BEGIN_DECL
+
+typedef struct {
+	unsigned int version;
+
+	/** For merge commits, the "mainline" is treated as the parent. */
+	unsigned int mainline;
+
+	git_merge_options merge_opts;
+	git_checkout_options checkout_opts;
+} git_cherry_pick_options;
+
+#define GIT_CHERRY_PICK_OPTIONS_VERSION 1
+#define GIT_CHERRY_PICK_OPTIONS_INIT {GIT_CHERRY_PICK_OPTIONS_VERSION, 0, GIT_MERGE_OPTIONS_INIT, GIT_CHECKOUT_OPTIONS_INIT}
+
+/**
+ * Initializes a `git_cherry_pick_options` with default values. Equivalent to
+ * creating an instance with GIT_CHERRY_PICK_OPTIONS_INIT.
+ *
+ * @param opts the `git_cherry_pick_options` instance to initialize.
+ * @param version the version of the struct; you should pass
+ *        `GIT_CHERRY_PICK_OPTIONS_VERSION` here.
+ * @return Zero on success; -1 on failure.
+ */
+GIT_EXTERN(int) git_cherry_pick_init_opts(
+	git_cherry_pick_options* opts,
+	int version);
+
+/**
+ * Cherry-picks the given commit against the given "our" commit, producing an
+ * index that reflects the result of the cherry-pick.
+ *
+ * The returned index must be freed explicitly with `git_index_free`.
+ *
+ * @param out pointer to store the index result in
+ * @param repo the repository that contains the given commits
+ * @param cherry_pick_commit the commit to cherry-pick
+ * @param our_commit the commit to revert against (eg, HEAD)
+ * @param mainline the parent of the revert commit, if it is a merge
+ * @param merge_tree_opts the merge tree options (or null for defaults)
+ * @return zero on success, -1 on failure.
+ */
+GIT_EXTERN(int) git_cherry_pick_commit(
+	git_index **out,
+	git_repository *repo,
+	git_commit *cherry_pick_commit,
+	git_commit *our_commit,
+	unsigned int mainline,
+	const git_merge_options *merge_options);
+
+/**
+ * Cherry-pick the given commit, producing changes in the index and working directory.
+ *
+ * @param repo the repository to cherry-pick
+ * @param commit the commit to cherry-pick
+ * @param cherry_pick_options the cherry-pick options (or null for defaults)
+ * @return zero on success, -1 on failure.
+ */
+GIT_EXTERN(int) git_cherry_pick(
+	git_repository *repo,
+	git_commit *commit,
+	const git_cherry_pick_options *cherry_pick_options);
+
+/** @} */
+GIT_END_DECL
+
+#endif
+

include/git2/errors.h

@@ -86,6 +86,7 @@ typedef enum {
 	GITERR_FILTER,
 	GITERR_REVERT,
 	GITERR_CALLBACK,
+	GITERR_CHERRYPICK,
 } git_error_t;
 
 /**

src/cherrypick.c

@@ -0,0 +1,230 @@
+/*
+* Copyright (C) the libgit2 contributors. All rights reserved.
+*
+* This file is part of libgit2, distributed under the GNU GPL v2 with
+* a Linking Exception. For full terms see the included COPYING file.
+*/
+
+#include "common.h"
+#include "repository.h"
+#include "filebuf.h"
+#include "merge.h"
+#include "vector.h"
+
+#include "git2/types.h"
+#include "git2/merge.h"
+#include "git2/cherrypick.h"
+#include "git2/commit.h"
+#include "git2/sys/commit.h"
+
+#define GIT_CHERRY_PICK_FILE_MODE		0666
+
+static int write_cherry_pick_head(
+	git_repository *repo,
+	const char *commit_oidstr)
+{
+	git_filebuf file = GIT_FILEBUF_INIT;
+	git_buf file_path = GIT_BUF_INIT;
+	int error = 0;
+
+	if ((error = git_buf_joinpath(&file_path, repo->path_repository, GIT_CHERRY_PICK_HEAD_FILE)) >= 0 &&
+		(error = git_filebuf_open(&file, file_path.ptr, GIT_FILEBUF_FORCE, GIT_CHERRY_PICK_FILE_MODE)) >= 0 &&
+		(error = git_filebuf_printf(&file, "%s\n", commit_oidstr)) >= 0)
+		error = git_filebuf_commit(&file);
+
+	if (error < 0)
+		git_filebuf_cleanup(&file);
+
+	git_buf_free(&file_path);
+
+	return error;
+}
+
+static int write_merge_msg(
+	git_repository *repo,
+	const char *commit_msg)
+{
+	git_filebuf file = GIT_FILEBUF_INIT;
+	git_buf file_path = GIT_BUF_INIT;
+	int error = 0;
+
+	if ((error = git_buf_joinpath(&file_path, repo->path_repository, GIT_MERGE_MSG_FILE)) < 0 ||
+		(error = git_filebuf_open(&file, file_path.ptr, GIT_FILEBUF_FORCE, GIT_CHERRY_PICK_FILE_MODE)) < 0 ||
+		(error = git_filebuf_printf(&file, "%s", commit_msg)) < 0)
+		goto cleanup;
+
+	error = git_filebuf_commit(&file);
+
+cleanup:
+	if (error < 0)
+		git_filebuf_cleanup(&file);
+
+	git_buf_free(&file_path);
+
+	return error;
+}
+
+static int cherry_pick_normalize_opts(
+	git_repository *repo,
+	git_cherry_pick_options *opts,
+	const git_cherry_pick_options *given,
+	const char *their_label)
+{
+	int error = 0;
+	unsigned int default_checkout_strategy = GIT_CHECKOUT_SAFE_CREATE |
+		GIT_CHECKOUT_ALLOW_CONFLICTS;
+
+	GIT_UNUSED(repo);
+
+	if (given != NULL)
+		memcpy(opts, given, sizeof(git_cherry_pick_options));
+	else {
+		git_cherry_pick_options default_opts = GIT_CHERRY_PICK_OPTIONS_INIT;
+		memcpy(opts, &default_opts, sizeof(git_cherry_pick_options));
+	}
+
+	if (!opts->checkout_opts.checkout_strategy)
+		opts->checkout_opts.checkout_strategy = default_checkout_strategy;
+
+	if (!opts->checkout_opts.our_label)
+		opts->checkout_opts.our_label = "HEAD";
+
+	if (!opts->checkout_opts.their_label)
+		opts->checkout_opts.their_label = their_label;
+
+	return error;
+}
+
+static int cherry_pick_state_cleanup(git_repository *repo)
+{
+	const char *state_files[] = { GIT_CHERRY_PICK_HEAD_FILE, GIT_MERGE_MSG_FILE };
+
+	return git_repository__cleanup_files(repo, state_files, ARRAY_SIZE(state_files));
+}
+
+static int cherry_pick_seterr(git_commit *commit, const char *fmt)
+{
+	char commit_oidstr[GIT_OID_HEXSZ + 1];
+
+	giterr_set(GITERR_CHERRYPICK, fmt,
+		git_oid_tostr(commit_oidstr, GIT_OID_HEXSZ + 1, git_commit_id(commit)));
+
+	return -1;
+}
+
+int git_cherry_pick_commit(
+	git_index **out,
+	git_repository *repo,
+	git_commit *cherry_pick_commit,
+	git_commit *our_commit,
+	unsigned int mainline,
+	const git_merge_options *merge_opts)
+{
+	git_commit *parent_commit = NULL;
+	git_tree *parent_tree = NULL, *our_tree = NULL, *cherry_pick_tree = NULL;
+	int parent = 0, error = 0;
+
+	assert(out && repo && cherry_pick_commit && our_commit);
+
+	if (git_commit_parentcount(cherry_pick_commit) > 1) {
+		if (!mainline)
+			return cherry_pick_seterr(cherry_pick_commit,
+				"Mainline branch is not specified but %s is a merge commit");
+
+		parent = mainline;
+	} else {
+		if (mainline)
+			return cherry_pick_seterr(cherry_pick_commit,
+				"Mainline branch specified but %s is not a merge commit");
+
+		parent = git_commit_parentcount(cherry_pick_commit);
+	}
+
+	if (parent &&
+		((error = git_commit_parent(&parent_commit, cherry_pick_commit, (parent - 1))) < 0 ||
+		(error = git_commit_tree(&parent_tree, parent_commit)) < 0))
+		goto done;
+
+	if ((error = git_commit_tree(&cherry_pick_tree, cherry_pick_commit)) < 0 ||
+		(error = git_commit_tree(&our_tree, our_commit)) < 0)
+		goto done;
+
+	error = git_merge_trees(out, repo, parent_tree, our_tree, cherry_pick_tree, merge_opts);
+
+done:
+	git_tree_free(parent_tree);
+	git_tree_free(our_tree);
+	git_tree_free(cherry_pick_tree);
+	git_commit_free(parent_commit);
+
+	return error;
+}
+
+int git_cherry_pick(
+	git_repository *repo,
+	git_commit *commit,
+	const git_cherry_pick_options *given_opts)
+{
+	git_cherry_pick_options opts;
+	git_reference *our_ref = NULL;
+	git_commit *our_commit = NULL;
+	char commit_oidstr[GIT_OID_HEXSZ + 1];
+	const char *commit_msg, *commit_summary;
+	git_buf their_label = GIT_BUF_INIT;
+	git_index *index_new = NULL, *index_repo = NULL;
+	int error = 0;
+
+	assert(repo && commit);
+
+	GITERR_CHECK_VERSION(given_opts, GIT_CHERRY_PICK_OPTIONS_VERSION, "git_cherry_pick_options");
+
+	if ((error = git_repository__ensure_not_bare(repo, "cherry-pick")) < 0)
+		return error;
+
+	if ((commit_msg = git_commit_message(commit)) == NULL ||
+		(commit_summary = git_commit_summary(commit)) == NULL) {
+		error = -1;
+		goto on_error;
+	}
+
+	git_oid_fmt(commit_oidstr, git_commit_id(commit));
+
+	if ((error = write_merge_msg(repo, commit_msg)) < 0 ||
+		(error = git_buf_printf(&their_label, "%.7s... %s", commit_oidstr, commit_summary)) < 0 ||
+		(error = cherry_pick_normalize_opts(repo, &opts, given_opts, git_buf_cstr(&their_label))) < 0 ||
+		(error = write_cherry_pick_head(repo, commit_oidstr)) < 0 ||
+		(error = git_repository_head(&our_ref, repo)) < 0 ||
+		(error = git_reference_peel((git_object **)&our_commit, our_ref, GIT_OBJ_COMMIT)) < 0 ||
+		(error = git_cherry_pick_commit(&index_new, repo, commit, our_commit, opts.mainline, &opts.merge_opts)) < 0 ||
+		(error = git_merge__indexes(repo, index_new)) < 0 ||
+		(error = git_repository_index(&index_repo, repo)) < 0 ||
+		(error = git_merge__append_conflicts_to_merge_msg(repo, index_repo)) < 0 ||
+		(error = git_checkout_index(repo, index_repo, &opts.checkout_opts)) < 0)
+		goto on_error;
+
+	goto done;
+
+on_error:
+	cherry_pick_state_cleanup(repo);
+
+done:
+	git_index_free(index_new);
+	git_index_free(index_repo);
+	git_commit_free(our_commit);
+	git_reference_free(our_ref);
+	git_buf_free(&their_label);
+
+	return error;
+}
+
+int git_cherry_pick_init_opts(git_cherry_pick_options* opts, int version)
+{
+	if (version != GIT_CHERRY_PICK_OPTIONS_VERSION) {
+		giterr_set(GITERR_INVALID, "Invalid version %d for git_cherry_pick_options", version);
+		return -1;
+	} else {
+		git_cherry_pick_options o = GIT_CHERRY_PICK_OPTIONS_INIT;
+		memcpy(opts, &o, sizeof(o));
+		return 0;
+	}
+}

src/merge.c

@@ -2469,6 +2469,47 @@ done:
 	return error;
 }
 
+int git_merge__append_conflicts_to_merge_msg(
+	git_repository *repo,
+	git_index *index)
+{
+	git_filebuf file = GIT_FILEBUF_INIT;
+	git_buf file_path = GIT_BUF_INIT;
+	const char *last = NULL;
+	size_t i;
+	int error;
+
+	if ((error = git_buf_joinpath(&file_path, repo->path_repository, GIT_MERGE_MSG_FILE)) < 0 ||
+		(error = git_filebuf_open(&file, file_path.ptr, GIT_FILEBUF_APPEND, GIT_MERGE_FILE_MODE)) < 0)
+		goto cleanup;
+
+	if (git_index_has_conflicts(index))
+		git_filebuf_printf(&file, "\nConflicts:\n");
+
+	for (i = 0; i < git_index_entrycount(index); i++) {
+		const git_index_entry *e = git_index_get_byindex(index, i);
+
+		if (git_index_entry_stage(e) == 0)
+			continue;
+
+		if (last == NULL || strcmp(e->path, last) != 0)
+			git_filebuf_printf(&file, "\t%s\n", e->path);
+
+		last = e->path;
+	}
+
+	error = git_filebuf_commit(&file);
+
+cleanup:
+	if (error < 0)
+		git_filebuf_cleanup(&file);
+
+	git_buf_free(&file_path);
+
+	return error;
+}
+
+
 static int merge_state_cleanup(git_repository *repo)
 {
 	const char *state_files[] = {
@@ -2621,6 +2662,7 @@ int git_merge(
 	if ((error = git_merge_trees(&index_new, repo, ancestor_tree, our_tree, their_trees[0], merge_opts)) < 0 ||
 		(error = git_merge__indexes(repo, index_new)) < 0 ||
 		(error = git_repository_index(&index_repo, repo)) < 0 ||
+		(error = git_merge__append_conflicts_to_merge_msg(repo, index_repo)) < 0 ||
 		(error = git_checkout_index(repo, index_repo, &checkout_opts)) < 0)
 		goto on_error;
 

src/merge.h

@@ -151,4 +151,6 @@ int git_merge__setup(
 
 int git_merge__indexes(git_repository *repo, git_index *index_new);
 
+int git_merge__append_conflicts_to_merge_msg(git_repository *repo, git_index *index);
+
 #endif

src/revert.c

@@ -201,6 +201,7 @@ int git_revert(
 		(error = git_revert_commit(&index_new, repo, commit, our_commit, opts.mainline, &opts.merge_opts)) < 0 ||
 		(error = git_merge__indexes(repo, index_new)) < 0 ||
 		(error = git_repository_index(&index_repo, repo)) < 0 ||
+		(error = git_merge__append_conflicts_to_merge_msg(repo, index_repo)) < 0 ||
 		(error = git_checkout_index(repo, index_repo, &opts.checkout_opts)) < 0)
 		goto on_error;
 

tests/cherrypick/bare.c

@@ -0,0 +1,106 @@
+#include "clar.h"
+#include "clar_libgit2.h"
+
+#include "buffer.h"
+#include "fileops.h"
+#include "git2/cherrypick.h"
+
+#include "../merge/merge_helpers.h"
+
+#define TEST_REPO_PATH "cherrypick"
+
+static git_repository *repo;
+
+void test_cherrypick_bare__initialize(void)
+{
+	repo = cl_git_sandbox_init(TEST_REPO_PATH);
+}
+
+void test_cherrypick_bare__cleanup(void)
+{
+	cl_git_sandbox_cleanup();
+}
+
+void test_cherrypick_bare__automerge(void)
+{
+	git_commit *head = NULL, *commit = NULL;
+	git_index *index = NULL;
+	git_oid head_oid, cherry_oid;
+
+	struct merge_index_entry merge_index_entries[] = {
+		{ 0100644, "38c05a857e831a7e759d83778bfc85d003e21c45", 0, "file1.txt" },
+		{ 0100644, "a661b5dec1004e2c62654ded3762370c27cf266b", 0, "file2.txt" },
+		{ 0100644, "df6b290e0bd6a89b01d69f66687e8abf385283ca", 0, "file3.txt" },
+	};
+
+	git_oid_fromstr(&head_oid, "d3d77487660ee3c0194ee01dc5eaf478782b1c7e");
+	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
+
+	git_oid_fromstr(&cherry_oid, "cfc4f0999a8367568e049af4f72e452d40828a15");
+	cl_git_pass(git_commit_lookup(&commit, repo, &cherry_oid));
+
+	cl_git_pass(git_cherry_pick_commit(&index, repo, commit, head, 0, NULL));
+	cl_assert(merge_test_index(index, merge_index_entries, 3));
+
+	git_index_free(index);
+	git_commit_free(head);
+	git_commit_free(commit);
+}
+
+void test_cherrypick_bare__conflicts(void)
+{
+	git_commit *head = NULL, *commit = NULL;
+	git_index *index = NULL;
+	git_oid head_oid, cherry_oid;
+
+	struct merge_index_entry merge_index_entries[] = {
+		{ 0100644, "242e7977ba73637822ffb265b46004b9b0e5153b", 0, "file1.txt" },
+		{ 0100644, "a58ca3fee5eb68b11adc2703e5843f968c9dad1e", 1, "file2.txt" },
+		{ 0100644, "bd6ffc8c6c41f0f85ff9e3d61c9479516bac0024", 2, "file2.txt" },
+		{ 0100644, "563f6473a3858f99b80e5f93c660512ed38e1e6f", 3, "file2.txt" },
+		{ 0100644, "28d9eb4208074ad1cc84e71ccc908b34573f05d2", 1, "file3.txt" },
+		{ 0100644, "1124c2c1ae07b26fded662d6c3f3631d9dc16f88", 2, "file3.txt" },
+		{ 0100644, "e233b9ed408a95e9d4b65fec7fc34943a556deb2", 3, "file3.txt" },
+	};
+
+	git_oid_fromstr(&head_oid, "bafbf6912c09505ac60575cd43d3f2aba3bd84d8");
+	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
+
+	git_oid_fromstr(&cherry_oid, "e9b63f3655b2ad80c0ff587389b5a9589a3a7110");
+	cl_git_pass(git_commit_lookup(&commit, repo, &cherry_oid));
+
+	cl_git_pass(git_cherry_pick_commit(&index, repo, commit, head, 0, NULL));
+	cl_assert(merge_test_index(index, merge_index_entries, 7));
+
+	git_index_free(index);
+	git_commit_free(head);
+	git_commit_free(commit);
+}
+
+void test_cherrypick_bare__orphan(void)
+{
+	git_commit *head = NULL, *commit = NULL;
+	git_index *index = NULL;
+	git_oid head_oid, cherry_oid;
+
+	struct merge_index_entry merge_index_entries[] = {
+		{ 0100644, "38c05a857e831a7e759d83778bfc85d003e21c45", 0, "file1.txt" },
+		{ 0100644, "a661b5dec1004e2c62654ded3762370c27cf266b", 0, "file2.txt" },
+		{ 0100644, "85a4a1d791973644f24c72f5e89420d3064cc452", 0, "file3.txt" },
+		{ 0100644, "9ccb9bf50c011fd58dcbaa65df917bf79539717f", 0, "orphan.txt" },
+	};
+
+	git_oid_fromstr(&head_oid, "d3d77487660ee3c0194ee01dc5eaf478782b1c7e");
+	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
+
+	git_oid_fromstr(&cherry_oid, "74f06b5bfec6d33d7264f73606b57a7c0b963819");
+	cl_git_pass(git_commit_lookup(&commit, repo, &cherry_oid));
+
+	cl_git_pass(git_cherry_pick_commit(&index, repo, commit, head, 0, NULL));
+	cl_assert(merge_test_index(index, merge_index_entries, 4));
+
+	git_index_free(index);
+	git_commit_free(head);
+	git_commit_free(commit);
+}
+

tests/cherrypick/workdir.c

@@ -0,0 +1,429 @@
+#include "clar.h"
+#include "clar_libgit2.h"
+
+#include "buffer.h"
+#include "fileops.h"
+#include "git2/cherrypick.h"
+
+#include "../merge/merge_helpers.h"
+
+#define TEST_REPO_PATH "cherrypick"
+
+static git_repository *repo;
+static git_index *repo_index;
+
+// Fixture setup and teardown
+void test_cherrypick_workdir__initialize(void)
+{
+	repo = cl_git_sandbox_init(TEST_REPO_PATH);
+	git_repository_index(&repo_index, repo);
+}
+
+void test_cherrypick_workdir__cleanup(void)
+{
+	git_index_free(repo_index);
+	cl_git_sandbox_cleanup();
+}
+
+/* git reset --hard d3d77487660ee3c0194ee01dc5eaf478782b1c7e
+ * git cherry-pick cfc4f0999a8367568e049af4f72e452d40828a15
+ * git cherry-pick 964ea3da044d9083181a88ba6701de9e35778bf4
+ * git cherry-pick a43a050c588d4e92f11a6b139680923e9728477d
+ */
+void test_cherrypick_workdir__automerge(void)
+{
+	git_oid head_oid;
+	git_signature *signature = NULL;
+	size_t i;
+
+	const char *cherry_pick_oids[] = {
+		"cfc4f0999a8367568e049af4f72e452d40828a15",
+		"964ea3da044d9083181a88ba6701de9e35778bf4",
+		"a43a050c588d4e92f11a6b139680923e9728477d",
+	};
+
+	struct merge_index_entry merge_index_entries[] = {
+		{ 0100644, "38c05a857e831a7e759d83778bfc85d003e21c45", 0, "file1.txt" },
+		{ 0100644, "a661b5dec1004e2c62654ded3762370c27cf266b", 0, "file2.txt" },
+		{ 0100644, "df6b290e0bd6a89b01d69f66687e8abf385283ca", 0, "file3.txt" },
+
+		{ 0100644, "38c05a857e831a7e759d83778bfc85d003e21c45", 0, "file1.txt" },
+		{ 0100644, "bd8fc3c59fb52d3c8b5907ace7defa5803f82419", 0, "file2.txt" },
+		{ 0100644, "df6b290e0bd6a89b01d69f66687e8abf385283ca", 0, "file3.txt" },
+
+		{ 0100644, "f06427bee380364bc7e0cb26a9245158e4726ce0", 0, "file1.txt" },
+		{ 0100644, "bd8fc3c59fb52d3c8b5907ace7defa5803f82419", 0, "file2.txt" },
+		{ 0100644, "df6b290e0bd6a89b01d69f66687e8abf385283ca", 0, "file3.txt" },
+	};
+
+	cl_git_pass(git_signature_new(&signature, "Picker", "picker@example.org", time(NULL), 0));
+
+	git_oid_fromstr(&head_oid, "d3d77487660ee3c0194ee01dc5eaf478782b1c7e");
+
+	for (i = 0; i < 3; ++i) {
+		git_commit *head = NULL, *commit = NULL;
+		git_oid cherry_oid, cherry_picked_oid, cherry_picked_tree_oid;
+		git_tree *cherry_picked_tree = NULL;
+
+		cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
+		cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL, NULL));
+
+		git_oid_fromstr(&cherry_oid, cherry_pick_oids[i]);
+		cl_git_pass(git_commit_lookup(&commit, repo, &cherry_oid));
+		cl_git_pass(git_cherry_pick(repo, commit, NULL));
+
+		cl_assert(git_path_exists(TEST_REPO_PATH "/.git/CHERRY_PICK_HEAD"));
+		cl_assert(git_path_exists(TEST_REPO_PATH "/.git/MERGE_MSG"));
+
+		cl_git_pass(git_index_write_tree(&cherry_picked_tree_oid, repo_index));
+		cl_git_pass(git_tree_lookup(&cherry_picked_tree, repo, &cherry_picked_tree_oid));
+		cl_git_pass(git_commit_create(&cherry_picked_oid, repo, "HEAD", signature, signature, NULL,
+			"Cherry picked!", cherry_picked_tree, 1, (const git_commit **)&head));
+
+		cl_assert(merge_test_index(repo_index, merge_index_entries + i * 3, 3));
+
+		git_oid_cpy(&head_oid, &cherry_picked_oid);
+
+		git_tree_free(cherry_picked_tree);
+		git_commit_free(head);
+		git_commit_free(commit);
+	}
+
+	git_signature_free(signature);
+}
+
+/* git reset --hard bafbf6912c09505ac60575cd43d3f2aba3bd84d8
+ * git cherry-pick e9b63f3655b2ad80c0ff587389b5a9589a3a7110
+ */
+void test_cherrypick_workdir__conflicts(void)
+{
+	git_commit *head = NULL, *commit = NULL;
+	git_oid head_oid, cherry_oid;
+	git_buf conflicting_buf = GIT_BUF_INIT, mergemsg_buf = GIT_BUF_INIT;
+
+	struct merge_index_entry merge_index_entries[] = {
+		{ 0100644, "242e7977ba73637822ffb265b46004b9b0e5153b", 0, "file1.txt" },
+		{ 0100644, "a58ca3fee5eb68b11adc2703e5843f968c9dad1e", 1, "file2.txt" },
+		{ 0100644, "bd6ffc8c6c41f0f85ff9e3d61c9479516bac0024", 2, "file2.txt" },
+		{ 0100644, "563f6473a3858f99b80e5f93c660512ed38e1e6f", 3, "file2.txt" },
+		{ 0100644, "28d9eb4208074ad1cc84e71ccc908b34573f05d2", 1, "file3.txt" },
+		{ 0100644, "1124c2c1ae07b26fded662d6c3f3631d9dc16f88", 2, "file3.txt" },
+		{ 0100644, "e233b9ed408a95e9d4b65fec7fc34943a556deb2", 3, "file3.txt" },
+	};
+
+	git_oid_fromstr(&head_oid, "bafbf6912c09505ac60575cd43d3f2aba3bd84d8");
+
+	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
+	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL, NULL));
+
+	git_oid_fromstr(&cherry_oid, "e9b63f3655b2ad80c0ff587389b5a9589a3a7110");
+	cl_git_pass(git_commit_lookup(&commit, repo, &cherry_oid));
+	cl_git_pass(git_cherry_pick(repo, commit, NULL));
+
+	cl_assert(git_path_exists(TEST_REPO_PATH "/.git/CHERRY_PICK_HEAD"));
+	cl_assert(git_path_exists(TEST_REPO_PATH "/.git/MERGE_MSG"));
+
+	cl_assert(merge_test_index(repo_index, merge_index_entries, 7));
+
+	cl_git_pass(git_futils_readbuffer(&mergemsg_buf,
+		TEST_REPO_PATH "/.git/MERGE_MSG"));
+	cl_assert(strcmp(git_buf_cstr(&mergemsg_buf),
+		"Change all files\n" \
+		"\n" \
+		"Conflicts:\n" \
+		"\tfile2.txt\n" \
+		"\tfile3.txt\n") == 0);
+
+	cl_git_pass(git_futils_readbuffer(&conflicting_buf,
+		TEST_REPO_PATH "/file2.txt"));
+
+	cl_assert(strcmp(git_buf_cstr(&conflicting_buf),
+		"!File 2\n" \
+		"File 2\n" \
+		"File 2\n" \
+		"File 2\n" \
+		"File 2\n" \
+		"File 2\n" \
+		"File 2\n" \
+		"File 2\n" \
+		"File 2\n" \
+		"File 2\n" \
+		"File 2!!\n" \
+		"File 2\n" \
+		"File 2\n" \
+		"File 2\n" \
+		"<<<<<<< HEAD\n" \
+		"File 2\n" \
+		"=======\n" \
+		"File 2!\n" \
+		"File 2\n" \
+		"File 2!\n" \
+		">>>>>>> e9b63f3... Change all files\n") == 0);
+
+	cl_git_pass(git_futils_readbuffer(&conflicting_buf,
+		TEST_REPO_PATH "/file3.txt"));
+
+	cl_assert(strcmp(git_buf_cstr(&conflicting_buf),
+		"!File 3\n" \
+		"File 3\n" \
+		"File 3\n" \
+		"File 3\n" \
+		"File 3\n" \
+		"File 3\n" \
+		"File 3\n" \
+		"File 3\n" \
+		"File 3\n" \
+		"File 3\n" \
+		"File 3\n" \
+		"File 3!!\n" \
+		"File 3\n" \
+		"File 3\n" \
+		"File 3\n" \
+		"<<<<<<< HEAD\n" \
+		"=======\n" \
+		"File 3!\n" \
+		"File 3!\n" \
+		">>>>>>> e9b63f3... Change all files\n") == 0);
+
+	git_commit_free(commit);
+	git_commit_free(head);
+	git_buf_free(&mergemsg_buf);
+	git_buf_free(&conflicting_buf);
+}
+
+/* git reset --hard bafbf6912c09505ac60575cd43d3f2aba3bd84d8
+ * git cherry-pick -X ours e9b63f3655b2ad80c0ff587389b5a9589a3a7110
+ */
+void test_cherrypick_workdir__conflict_use_ours(void)
+{
+	git_commit *head = NULL, *commit = NULL;
+	git_oid head_oid, cherry_oid;
+	git_cherry_pick_options opts = GIT_CHERRY_PICK_OPTIONS_INIT;
+
+	struct merge_index_entry merge_index_entries[] = {
+		{ 0100644, "242e7977ba73637822ffb265b46004b9b0e5153b", 0, "file1.txt" },
+		{ 0100644, "a58ca3fee5eb68b11adc2703e5843f968c9dad1e", 1, "file2.txt" },
+		{ 0100644, "bd6ffc8c6c41f0f85ff9e3d61c9479516bac0024", 2, "file2.txt" },
+		{ 0100644, "563f6473a3858f99b80e5f93c660512ed38e1e6f", 3, "file2.txt" },
+		{ 0100644, "28d9eb4208074ad1cc84e71ccc908b34573f05d2", 1, "file3.txt" },
+		{ 0100644, "1124c2c1ae07b26fded662d6c3f3631d9dc16f88", 2, "file3.txt" },
+		{ 0100644, "e233b9ed408a95e9d4b65fec7fc34943a556deb2", 3, "file3.txt" },
+	};
+
+	struct merge_index_entry merge_filesystem_entries[] = {
+		{ 0100644, "242e7977ba73637822ffb265b46004b9b0e5153b", 0, "file1.txt" },
+		{ 0100644, "bd6ffc8c6c41f0f85ff9e3d61c9479516bac0024", 0, "file2.txt" },
+		{ 0100644, "1124c2c1ae07b26fded662d6c3f3631d9dc16f88", 0, "file3.txt" },
+	};
+
+	/* leave the index in a conflicted state, but checkout "ours" to the workdir */
+	opts.checkout_opts.checkout_strategy = GIT_CHECKOUT_SAFE | GIT_CHECKOUT_USE_OURS;
+
+	git_oid_fromstr(&head_oid, "bafbf6912c09505ac60575cd43d3f2aba3bd84d8");
+
+	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
+	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL, NULL));
+
+	git_oid_fromstr(&cherry_oid, "e9b63f3655b2ad80c0ff587389b5a9589a3a7110");
+	cl_git_pass(git_commit_lookup(&commit, repo, &cherry_oid));
+	cl_git_pass(git_cherry_pick(repo, commit, &opts));
+
+	cl_assert(merge_test_index(repo_index, merge_index_entries, 7));
+	cl_assert(merge_test_workdir(repo, merge_filesystem_entries, 3));
+
+	/* resolve conflicts in the index by taking "ours" */
+	opts.merge_opts.file_favor = GIT_MERGE_FILE_FAVOR_OURS;
+
+	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL, NULL));
+	cl_git_pass(git_cherry_pick(repo, commit, &opts));
+
+	cl_assert(merge_test_index(repo_index, merge_filesystem_entries, 3));
+	cl_assert(merge_test_workdir(repo, merge_filesystem_entries, 3));
+
+	git_commit_free(commit);
+	git_commit_free(head);
+}
+
+/* git reset --hard cfc4f0999a8367568e049af4f72e452d40828a15
+ * git cherry-pick 2a26c7e88b285613b302ba76712bc998863f3cbc
+ */
+void test_cherrypick_workdir__rename(void)
+{
+	git_commit *head, *commit;
+	git_oid head_oid, cherry_oid;
+	git_cherry_pick_options opts = GIT_CHERRY_PICK_OPTIONS_INIT;
+
+	struct merge_index_entry merge_index_entries[] = {
+		{ 0100644, "19c5c7207054604b69c84d08a7571ef9672bb5c2", 0, "file1.txt" },
+		{ 0100644, "a58ca3fee5eb68b11adc2703e5843f968c9dad1e", 0, "file2.txt" },
+		{ 0100644, "28d9eb4208074ad1cc84e71ccc908b34573f05d2", 0, "file3.txt.renamed" },
+	};
+
+	opts.merge_opts.flags |= GIT_MERGE_TREE_FIND_RENAMES;
+	opts.merge_opts.rename_threshold = 50;
+
+	git_oid_fromstr(&head_oid, "cfc4f0999a8367568e049af4f72e452d40828a15");
+	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
+	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL, NULL));
+
+	git_oid_fromstr(&cherry_oid, "2a26c7e88b285613b302ba76712bc998863f3cbc");
+	cl_git_pass(git_commit_lookup(&commit, repo, &cherry_oid));
+	cl_git_pass(git_cherry_pick(repo, commit, &opts));
+
+	cl_assert(merge_test_index(repo_index, merge_index_entries, 3));
+
+	git_commit_free(commit);
+	git_commit_free(head);
+}
+
+/* git reset --hard 44cd2ed2052c9c68f9a439d208e9614dc2a55c70
+ * git cherry-pick 2a26c7e88b285613b302ba76712bc998863f3cbc
+ */
+void test_cherrypick_workdir__both_renamed(void)
+{
+	git_commit *head, *commit;
+	git_oid head_oid, cherry_oid;
+	git_buf mergemsg_buf = GIT_BUF_INIT;
+	git_cherry_pick_options opts = GIT_CHERRY_PICK_OPTIONS_INIT;
+
+	struct merge_index_entry merge_index_entries[] = {
+		{ 0100644, "19c5c7207054604b69c84d08a7571ef9672bb5c2", 0, "file1.txt" },
+		{ 0100644, "a58ca3fee5eb68b11adc2703e5843f968c9dad1e", 0, "file2.txt" },
+		{ 0100644, "e233b9ed408a95e9d4b65fec7fc34943a556deb2", 1, "file3.txt" },
+		{ 0100644, "e233b9ed408a95e9d4b65fec7fc34943a556deb2", 3, "file3.txt.renamed" },
+		{ 0100644, "28d9eb4208074ad1cc84e71ccc908b34573f05d2", 2, "file3.txt.renamed_on_branch" },
+	};
+
+	opts.merge_opts.flags |= GIT_MERGE_TREE_FIND_RENAMES;
+	opts.merge_opts.rename_threshold = 50;
+
+	git_oid_fromstr(&head_oid, "44cd2ed2052c9c68f9a439d208e9614dc2a55c70");
+	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
+	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL, NULL));
+
+	git_oid_fromstr(&cherry_oid, "2a26c7e88b285613b302ba76712bc998863f3cbc");
+	cl_git_pass(git_commit_lookup(&commit, repo, &cherry_oid));
+	cl_git_pass(git_cherry_pick(repo, commit, &opts));
+
+	cl_assert(merge_test_index(repo_index, merge_index_entries, 5));
+
+	cl_git_pass(git_futils_readbuffer(&mergemsg_buf,
+		TEST_REPO_PATH "/.git/MERGE_MSG"));
+	cl_assert(strcmp(git_buf_cstr(&mergemsg_buf),
+		"Renamed file3.txt -> file3.txt.renamed\n" \
+		"\n" \
+		"Conflicts:\n" \
+		"\tfile3.txt\n" \
+		"\tfile3.txt.renamed\n" \
+		"\tfile3.txt.renamed_on_branch\n") == 0);
+
+	git_buf_free(&mergemsg_buf);
+	git_commit_free(commit);
+	git_commit_free(head);
+}
+
+void test_cherrypick_workdir__nonmerge_fails_mainline_specified(void)
+{
+	git_reference *head;
+	git_commit *commit;
+	git_cherry_pick_options opts = GIT_CHERRY_PICK_OPTIONS_INIT;
+
+	cl_git_pass(git_repository_head(&head, repo));
+	cl_git_pass(git_reference_peel((git_object **)&commit, head, GIT_OBJ_COMMIT));
+
+	opts.mainline = 1;
+	cl_must_fail(git_cherry_pick(repo, commit, &opts));
+	cl_assert(!git_path_exists(TEST_REPO_PATH "/.git/CHERRY_PICK_HEAD"));
+	cl_assert(!git_path_exists(TEST_REPO_PATH "/.git/MERGE_MSG"));
+
+	git_reference_free(head);
+	git_commit_free(commit);
+}
+
+/* git reset --hard cfc4f0999a8367568e049af4f72e452d40828a15
+ * git cherry-pick abe4603bc7cd5b8167a267e0e2418fd2348f8cff
+ */
+void test_cherrypick_workdir__merge_fails_without_mainline_specified(void)
+{
+	git_commit *head, *commit;
+	git_oid head_oid, cherry_oid;
+
+	git_oid_fromstr(&head_oid, "cfc4f0999a8367568e049af4f72e452d40828a15");
+	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
+	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL, NULL));
+
+	git_oid_fromstr(&cherry_oid, "abe4603bc7cd5b8167a267e0e2418fd2348f8cff");
+	cl_git_pass(git_commit_lookup(&commit, repo, &cherry_oid));
+
+	cl_must_fail(git_cherry_pick(repo, commit, NULL));
+	cl_assert(!git_path_exists(TEST_REPO_PATH "/.git/CHERRY_PICK_HEAD"));
+	cl_assert(!git_path_exists(TEST_REPO_PATH "/.git/MERGE_MSG"));
+
+	git_commit_free(commit);
+	git_commit_free(head);
+}
+
+/* git reset --hard cfc4f0999a8367568e049af4f72e452d40828a15
+ * git cherry-pick -m1 abe4603bc7cd5b8167a267e0e2418fd2348f8cff
+ */
+void test_cherrypick_workdir__merge_first_parent(void)
+{
+	git_commit *head, *commit;
+	git_oid head_oid, cherry_oid;
+	git_cherry_pick_options opts = GIT_CHERRY_PICK_OPTIONS_INIT;
+
+	struct merge_index_entry merge_index_entries[] = {
+		{ 0100644, "f90f9dcbdac2cce5cc166346160e19cb693ef4e8", 0, "file1.txt" },
+		{ 0100644, "563f6473a3858f99b80e5f93c660512ed38e1e6f", 0, "file2.txt" },
+		{ 0100644, "e233b9ed408a95e9d4b65fec7fc34943a556deb2", 0, "file3.txt" },
+	};
+
+	opts.mainline = 1;
+
+	git_oid_fromstr(&head_oid, "cfc4f0999a8367568e049af4f72e452d40828a15");
+	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
+	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL, NULL));
+
+	git_oid_fromstr(&cherry_oid, "abe4603bc7cd5b8167a267e0e2418fd2348f8cff");
+	cl_git_pass(git_commit_lookup(&commit, repo, &cherry_oid));
+
+	cl_git_pass(git_cherry_pick(repo, commit, &opts));
+
+	cl_assert(merge_test_index(repo_index, merge_index_entries, 3));
+
+	git_commit_free(commit);
+	git_commit_free(head);
+}
+
+/* git reset --hard cfc4f0999a8367568e049af4f72e452d40828a15
+ * git cherry-pick -m2 abe4603bc7cd5b8167a267e0e2418fd2348f8cff
+ */
+void test_cherrypick_workdir__merge_second_parent(void)
+{
+	git_commit *head, *commit;
+	git_oid head_oid, cherry_oid;
+	git_cherry_pick_options opts = GIT_CHERRY_PICK_OPTIONS_INIT;
+
+	struct merge_index_entry merge_index_entries[] = {
+		{ 0100644, "487434cace79238a7091e2220611d4f20a765690", 0, "file1.txt" },
+		{ 0100644, "e5183bfd18e3a0a691fadde2f0d5610b73282d31", 0, "file2.txt" },
+		{ 0100644, "409a1bec58bf35348e8b62b72bb9c1f45cf5a587", 0, "file3.txt" },
+	};
+
+	opts.mainline = 2;
+
+	git_oid_fromstr(&head_oid, "cfc4f0999a8367568e049af4f72e452d40828a15");
+	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
+	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD, NULL, NULL));
+
+	git_oid_fromstr(&cherry_oid, "abe4603bc7cd5b8167a267e0e2418fd2348f8cff");
+	cl_git_pass(git_commit_lookup(&commit, repo, &cherry_oid));
+
+	cl_git_pass(git_cherry_pick(repo, commit, &opts));
+
+	cl_assert(merge_test_index(repo_index, merge_index_entries, 3));
+
+	git_commit_free(commit);
+	git_commit_free(head);
+}
+

tests/merge/workdir/simple.c

@@ -214,7 +214,7 @@ void test_merge_workdir_simple__automerge_crlf(void)
 
 void test_merge_workdir_simple__mergefile(void)
 {
-	git_buf conflicting_buf = GIT_BUF_INIT;
+	git_buf conflicting_buf = GIT_BUF_INIT, mergemsg_buf = GIT_BUF_INIT;
 
 	struct merge_index_entry merge_index_entries[] = {
 		ADDED_IN_MASTER_INDEX_ENTRY,
@@ -240,7 +240,15 @@ void test_merge_workdir_simple__mergefile(void)
 	cl_git_pass(git_futils_readbuffer(&conflicting_buf,
 		TEST_REPO_PATH "/conflicting.txt"));
 	cl_assert(strcmp(conflicting_buf.ptr, CONFLICTING_MERGE_FILE) == 0);
+	cl_git_pass(git_futils_readbuffer(&mergemsg_buf,
+		TEST_REPO_PATH "/.git/MERGE_MSG"));
+	cl_assert(strcmp(git_buf_cstr(&mergemsg_buf),
+		"Merge commit '7cb63eed597130ba4abb87b3e544b85021905520'\n" \
+		"\n" \
+		"Conflicts:\n" \
+		"\tconflicting.txt\n") == 0);
 	git_buf_free(&conflicting_buf);
+	git_buf_free(&mergemsg_buf);
 
 	cl_assert(merge_test_index(repo_index, merge_index_entries, 8));
 	cl_assert(merge_test_reuc(repo_index, merge_reuc_entries, 3));