merge_file should use more aggressive levels

The default merge_file level was XDL_MERGE_MINIMAL, which will
produce conflicts where there should not be in the case where
both sides were changed identically.  Change the defaults to be
more aggressive (XDL_MERGE_ZEALOUS) which will more aggressively
compress non-conflicts.  This matches git.git's defaults.

Increase testing around reverting a previously reverted commit to
illustrate this problem.

33 files changed, 264 insertions, 33 deletions

diff --git a/include/git2/merge.h b/include/git2/merge.h
index 8a1dfec2e..1888babd1 100644
--- a/include/git2/merge.h
+++ b/include/git2/merge.h
@@ -32,14 +32,21 @@ typedef enum {
 } git_merge_tree_flag_t;
 
 /**
- * Automerge options for `git_merge_trees_opts`.
+ * Merge file options for `git_merge_trees_opts`.
  */
 typedef enum {
-	GIT_MERGE_AUTOMERGE_NORMAL = 0,
-	GIT_MERGE_AUTOMERGE_NONE = 1,
-	GIT_MERGE_AUTOMERGE_FAVOR_OURS = 2,
-	GIT_MERGE_AUTOMERGE_FAVOR_THEIRS = 3,
-} git_merge_automerge_flags;
+	/* Produce a conflict in a file when two similar regions are changed. */
+	GIT_MERGE_FILE_FAVOR_NORMAL = 0,
+
+	/* Do not attempt to produce an automerged file during tree merge. */
+	GIT_MERGE_FILE_FAVOR_NO_MERGE = 1,
+
+	/* Produce a file containing the "ours" side of conflicting regions. */
+	GIT_MERGE_FILE_FAVOR_OURS = 2,
+
+	/* Produce a file containing the "theirs" side of conflicting regions. */
+	GIT_MERGE_FILE_FAVOR_THEIRS = 3,
+} git_merge_file_favor_t;
 
 
 typedef struct {
@@ -58,7 +65,7 @@ typedef struct {
 	git_diff_similarity_metric *metric;
 
 	/** Flags for automerging content. */
-	git_merge_automerge_flags automerge_flags;
+	git_merge_file_favor_t file_favor;
 } git_merge_tree_opts;
 
 #define GIT_MERGE_TREE_OPTS_VERSION 1
diff --git a/src/checkout.c b/src/checkout.c
index e642c975e..cc49800a2 100644
--- a/src/checkout.c
+++ b/src/checkout.c
@@ -1626,6 +1626,7 @@ static int checkout_write_merge(
 {
 	git_buf our_label = GIT_BUF_INIT, their_label = GIT_BUF_INIT,
 		path_suffixed = GIT_BUF_INIT, path_workdir = GIT_BUF_INIT;
+	git_merge_file_options merge_file_opts = GIT_MERGE_FILE_OPTIONS_INIT;
 	git_merge_file_input ancestor = GIT_MERGE_FILE_INPUT_INIT,
 		ours = GIT_MERGE_FILE_INPUT_INIT,
 		theirs = GIT_MERGE_FILE_INPUT_INIT;
@@ -1662,7 +1663,7 @@ static int checkout_write_merge(
 		theirs.label = git_buf_cstr(&their_label);
 	}
 
-	if ((error = git_merge_files(&result, &ancestor, &ours, &theirs, 0)) < 0)
+	if ((error = git_merge_files(&result, &ancestor, &ours, &theirs, &merge_file_opts)) < 0)
 		goto done;
 
 	if (result.path == NULL || result.mode == 0) {
diff --git a/src/merge.c b/src/merge.c
index c0be37dd8..3ac9167e3 100644
--- a/src/merge.c
+++ b/src/merge.c
@@ -511,8 +511,9 @@ static int merge_conflict_resolve_automerge(
 	int *resolved,
 	git_merge_diff_list *diff_list,
 	const git_merge_diff *conflict,
-	unsigned int automerge_flags)
+	unsigned int merge_file_favor)
 {
+	git_merge_file_options merge_file_opts = GIT_MERGE_FILE_OPTIONS_INIT;
 	git_merge_file_input ancestor = GIT_MERGE_FILE_INPUT_INIT,
 		ours = GIT_MERGE_FILE_INPUT_INIT,
 		theirs = GIT_MERGE_FILE_INPUT_INIT;
@@ -526,9 +527,11 @@ static int merge_conflict_resolve_automerge(
 
 	*resolved = 0;
 
-	if (automerge_flags == GIT_MERGE_AUTOMERGE_NONE)
+	if (merge_file_favor == GIT_MERGE_FILE_FAVOR_NO_MERGE)
 		return 0;
 
+	merge_file_opts.favor = merge_file_favor;
+
 	/* Reject D/F conflicts */
 	if (conflict->type == GIT_MERGE_DIFF_DIRECTORY_FILE)
 		return 0;
@@ -552,7 +555,7 @@ static int merge_conflict_resolve_automerge(
 		(error = git_merge_file_input_from_index_entry(&ancestor, diff_list->repo, &conflict->ancestor_entry)) < 0 ||
 		(error = git_merge_file_input_from_index_entry(&ours, diff_list->repo, &conflict->our_entry)) < 0 ||
 		(error = git_merge_file_input_from_index_entry(&theirs, diff_list->repo, &conflict->their_entry)) < 0 ||
-		(error = git_merge_files(&result, &ancestor, &ours, &theirs, automerge_flags)) < 0 ||
+		(error = git_merge_files(&result, &ancestor, &ours, &theirs, &merge_file_opts)) < 0 ||
 		!result.automergeable ||
 		(error = git_odb_write(&automerge_oid, odb, result.data, result.len, GIT_OBJ_BLOB)) < 0)
 		goto done;
@@ -586,7 +589,7 @@ static int merge_conflict_resolve(
 	int *out,
 	git_merge_diff_list *diff_list,
 	const git_merge_diff *conflict,
-	unsigned int automerge_flags)
+	unsigned int merge_file_favor)
 {
 	int resolved = 0;
 	int error = 0;
@@ -596,14 +599,14 @@ static int merge_conflict_resolve(
 	if ((error = merge_conflict_resolve_trivial(&resolved, diff_list, conflict)) < 0)
 		goto done;
 
-	if (automerge_flags != GIT_MERGE_AUTOMERGE_NONE) {
+	if (merge_file_favor != GIT_MERGE_FILE_FAVOR_NO_MERGE) {
 		if (!resolved && (error = merge_conflict_resolve_one_removed(&resolved, diff_list, conflict)) < 0)
 			goto done;
 
 		if (!resolved && (error = merge_conflict_resolve_one_renamed(&resolved, diff_list, conflict)) < 0)
 			goto done;
 
-		if (!resolved && (error = merge_conflict_resolve_automerge(&resolved, diff_list, conflict, automerge_flags)) < 0)
+		if (!resolved && (error = merge_conflict_resolve_automerge(&resolved, diff_list, conflict, merge_file_favor)) < 0)
 			goto done;
 	}
 
@@ -1589,7 +1592,7 @@ int git_merge_trees(
 	git_vector_foreach(&changes, i, conflict) {
 		int resolved = 0;
 
-		if ((error = merge_conflict_resolve(&resolved, diff_list, conflict, opts.automerge_flags)) < 0)
+		if ((error = merge_conflict_resolve(&resolved, diff_list, conflict, opts.file_favor)) < 0)
 			goto done;
 
 		if (!resolved)
diff --git a/src/merge_file.c b/src/merge_file.c
index 48fc46e57..d13190276 100644
--- a/src/merge_file.c
+++ b/src/merge_file.c
@@ -130,7 +130,7 @@ int git_merge_files(
 	git_merge_file_input *ancestor,
 	git_merge_file_input *ours,
 	git_merge_file_input *theirs,
-	git_merge_automerge_flags flags)
+	git_merge_file_options *opts)
 {
 	xmparam_t xmparam;
 	mmbuffer_t mmbuffer;
@@ -152,12 +152,15 @@ int git_merge_files(
 	out->path = merge_file_best_path(ancestor, ours, theirs);
 	out->mode = merge_file_best_mode(ancestor, ours, theirs);
 
-	if (flags == GIT_MERGE_AUTOMERGE_FAVOR_OURS)
+	if (opts && opts->favor == GIT_MERGE_FILE_FAVOR_OURS)
 		xmparam.favor = XDL_MERGE_FAVOR_OURS;
-
-	if (flags == GIT_MERGE_AUTOMERGE_FAVOR_THEIRS)
+	else if (opts && opts->favor == GIT_MERGE_FILE_FAVOR_THEIRS)
 		xmparam.favor = XDL_MERGE_FAVOR_THEIRS;
 
+	xmparam.level = 
+		(opts && (opts->flags & GIT_MERGE_FILE_SIMPLIFY_ALNUM)) ?
+		XDL_MERGE_ZEALOUS_ALNUM : XDL_MERGE_ZEALOUS;
+
 	if ((xdl_result = xdl_merge(&ancestor->mmfile, &ours->mmfile,
 		&theirs->mmfile, &xmparam, &mmbuffer)) < 0) {
 		giterr_set(GITERR_MERGE, "Failed to merge files.");
diff --git a/src/merge_file.h b/src/merge_file.h
index 0af2f0a57..5d7ea9752 100644
--- a/src/merge_file.h
+++ b/src/merge_file.h
@@ -34,6 +34,18 @@ typedef struct {
 
 #define GIT_MERGE_FILE_RESULT_INIT	{0}
 
+typedef enum {
+	/* Condense non-alphanumeric regions for simplified diff file */
+	GIT_MERGE_FILE_SIMPLIFY_ALNUM = (1 << 0),
+} git_merge_file_flags_t;
+
+typedef struct {
+	git_merge_file_favor_t favor;
+	git_merge_file_flags_t flags;
+} git_merge_file_options;
+
+#define GIT_MERGE_FILE_OPTIONS_INIT	{0}
+
 int git_merge_file_input_from_index_entry(
 	git_merge_file_input *input,
 	git_repository *repo,
@@ -49,7 +61,7 @@ int git_merge_files(
 	git_merge_file_input *ancestor,
 	git_merge_file_input *ours,
 	git_merge_file_input *theirs,
-	git_merge_automerge_flags flags);
+	git_merge_file_options *opts);
 
 GIT_INLINE(void) git_merge_file_input_free(git_merge_file_input *input)
 {
diff --git a/tests/merge/trees/automerge.c b/tests/merge/trees/automerge.c
index 746ce5068..ebc6e271d 100644
--- a/tests/merge/trees/automerge.c
+++ b/tests/merge/trees/automerge.c
@@ -149,7 +149,7 @@ void test_merge_trees_automerge__favor_ours(void)
 		REMOVED_IN_MASTER_REUC_ENTRY,
 	};
 
-	opts.automerge_flags = GIT_MERGE_AUTOMERGE_FAVOR_OURS;
+	opts.file_favor = GIT_MERGE_FILE_FAVOR_OURS;
 
 	cl_git_pass(merge_trees_from_branches(&index, repo, "master", THEIRS_AUTOMERGE_BRANCH, &opts));
 
@@ -180,7 +180,7 @@ void test_merge_trees_automerge__favor_theirs(void)
 		REMOVED_IN_MASTER_REUC_ENTRY,
 	};
 
-	opts.automerge_flags = GIT_MERGE_AUTOMERGE_FAVOR_THEIRS;
+	opts.file_favor = GIT_MERGE_FILE_FAVOR_THEIRS;
 
 	cl_git_pass(merge_trees_from_branches(&index, repo, "master", THEIRS_AUTOMERGE_BRANCH, &opts));
 
diff --git a/tests/merge/trees/trivial.c b/tests/merge/trees/trivial.c
index bfd5dfed3..244cd3223 100644
--- a/tests/merge/trees/trivial.c
+++ b/tests/merge/trees/trivial.c
@@ -33,7 +33,7 @@ static int merge_trivial(git_index **index, const char *ours, const char *theirs
 	git_buf branch_buf = GIT_BUF_INIT;
 	git_merge_tree_opts opts = GIT_MERGE_TREE_OPTS_INIT;
 
-	opts.automerge_flags |= automerge ? 0 : GIT_MERGE_AUTOMERGE_NONE;
+	opts.file_favor |= automerge ? 0 : GIT_MERGE_FILE_FAVOR_NO_MERGE;
 
 	git_buf_printf(&branch_buf, "%s%s", GIT_REFS_HEADS_DIR, ours);
 	cl_git_pass(git_reference_name_to_id(&our_oid, repo, branch_buf.ptr));
diff --git a/tests/merge/workdir/simple.c b/tests/merge/workdir/simple.c
index 98dca53ef..2142fc4f9 100644
--- a/tests/merge/workdir/simple.c
+++ b/tests/merge/workdir/simple.c
@@ -113,7 +113,7 @@ void test_merge_workdir_simple__cleanup(void)
 	cl_git_sandbox_cleanup();
 }
 
-static git_merge_result *merge_simple_branch(int automerge_flags, int checkout_strategy)
+static git_merge_result *merge_simple_branch(int merge_file_favor, int checkout_strategy)
 {
 	git_oid their_oids[1];
 	git_merge_head *their_heads[1];
@@ -123,7 +123,7 @@ static git_merge_result *merge_simple_branch(int automerge_flags, int checkout_s
 	cl_git_pass(git_oid_fromstr(&their_oids[0], THEIRS_SIMPLE_OID));
 	cl_git_pass(git_merge_head_from_oid(&their_heads[0], repo, &their_oids[0]));
 
-	opts.merge_tree_opts.automerge_flags = automerge_flags;
+	opts.merge_tree_opts.file_favor = merge_file_favor;
 	opts.checkout_opts.checkout_strategy = checkout_strategy;
 	cl_git_pass(git_merge(&result, repo, (const git_merge_head **)their_heads, 1, &opts));
 
@@ -336,7 +336,7 @@ void test_merge_workdir_simple__favor_ours(void)
 		REMOVED_IN_MASTER_REUC_ENTRY,
 	};
 
-	cl_assert(result = merge_simple_branch(GIT_MERGE_AUTOMERGE_FAVOR_OURS, 0));
+	cl_assert(result = merge_simple_branch(GIT_MERGE_FILE_FAVOR_OURS, 0));
 	cl_assert(!git_merge_result_is_fastforward(result));
 
 	cl_assert(merge_test_index(repo_index, merge_index_entries, 6));
@@ -365,7 +365,7 @@ void test_merge_workdir_simple__favor_theirs(void)
 		REMOVED_IN_MASTER_REUC_ENTRY,
 	};
 
-	cl_assert(result = merge_simple_branch(GIT_MERGE_AUTOMERGE_FAVOR_THEIRS, 0));
+	cl_assert(result = merge_simple_branch(GIT_MERGE_FILE_FAVOR_THEIRS, 0));
 	cl_assert(!git_merge_result_is_fastforward(result));
 
 	cl_assert(merge_test_index(repo_index, merge_index_entries, 6));
@@ -414,7 +414,7 @@ void test_merge_workdir_simple__directory_file(void)
 	cl_git_pass(git_oid_fromstr(&their_oids[0], THEIRS_DIRECTORY_FILE));
 	cl_git_pass(git_merge_head_from_oid(&their_heads[0], repo, &their_oids[0]));
 
-	opts.merge_tree_opts.automerge_flags = 0;
+	opts.merge_tree_opts.file_favor = 0;
 	cl_git_pass(git_merge(&result, repo, (const git_merge_head **)their_heads, 1, &opts));
 
 	cl_assert(merge_test_index(repo_index, merge_index_entries, 20));
@@ -447,7 +447,7 @@ void test_merge_workdir_simple__unrelated(void)
 	cl_git_pass(git_oid_fromstr(&their_oids[0], THEIRS_UNRELATED_PARENT));
 	cl_git_pass(git_merge_head_from_oid(&their_heads[0], repo, &their_oids[0]));
 
-	opts.merge_tree_opts.automerge_flags = 0;
+	opts.merge_tree_opts.file_favor = 0;
 	cl_git_pass(git_merge(&result, repo, (const git_merge_head **)their_heads, 1, &opts));
 
 	cl_assert(merge_test_index(repo_index, merge_index_entries, 9));
@@ -480,7 +480,7 @@ void test_merge_workdir_simple__unrelated_with_conflicts(void)
 	cl_git_pass(git_oid_fromstr(&their_oids[0], THEIRS_UNRELATED_OID));
 	cl_git_pass(git_merge_head_from_oid(&their_heads[0], repo, &their_oids[0]));
 
-	opts.merge_tree_opts.automerge_flags = 0;
+	opts.merge_tree_opts.file_favor = 0;
 	cl_git_pass(git_merge(&result, repo, (const git_merge_head **)their_heads, 1, &opts));
 
 	cl_assert(merge_test_index(repo_index, merge_index_entries, 11));
diff --git a/tests/merge/workdir/trivial.c b/tests/merge/workdir/trivial.c
index df18b0e0b..ebf09095c 100644
--- a/tests/merge/workdir/trivial.c
+++ b/tests/merge/workdir/trivial.c
@@ -39,7 +39,7 @@ static int merge_trivial(const char *ours, const char *theirs, bool automerge)
 
 	checkout_opts.checkout_strategy = GIT_CHECKOUT_FORCE;
 
-	opts.merge_tree_opts.automerge_flags |= automerge ? 0 : GIT_MERGE_AUTOMERGE_NONE;
+	opts.merge_tree_opts.file_favor |= automerge ? 0 : GIT_MERGE_FILE_FAVOR_NO_MERGE;
 
 	git_buf_printf(&branch_buf, "%s%s", GIT_REFS_HEADS_DIR, ours);
 	cl_git_pass(git_reference_symbolic_create(&our_ref, repo, "HEAD", branch_buf.ptr, 1, NULL, NULL));
diff --git a/tests/resources/revert/.gitted/index b/tests/resources/revert/.gitted/index
index 87419ff57..3513c04a6 100644
--- a/tests/resources/revert/.gitted/index
+++ b/tests/resources/revert/.gitted/index
diff --git a/tests/resources/revert/.gitted/objects/0a/d19525be6d8cae5e5deb2770fc244b65255057 b/tests/resources/revert/.gitted/objects/0a/d19525be6d8cae5e5deb2770fc244b65255057
new file mode 100644
index 000000000..4aa0459d8
--- /dev/null
+++ b/tests/resources/revert/.gitted/objects/0a/d19525be6d8cae5e5deb2770fc244b65255057
diff --git a/tests/resources/revert/.gitted/objects/13/a6fdfd10bd74b1f258fb58801215985dd2e797 b/tests/resources/revert/.gitted/objects/13/a6fdfd10bd74b1f258fb58801215985dd2e797
new file mode 100644
index 000000000..3c54aab0c
--- /dev/null
+++ b/tests/resources/revert/.gitted/objects/13/a6fdfd10bd74b1f258fb58801215985dd2e797
diff --git a/tests/resources/revert/.gitted/objects/1b/c915c5cb7185a9438de28a7b1a7dfe8c01ee7f b/tests/resources/revert/.gitted/objects/1b/c915c5cb7185a9438de28a7b1a7dfe8c01ee7f
new file mode 100644
index 000000000..0a6955b5d
--- /dev/null
+++ b/tests/resources/revert/.gitted/objects/1b/c915c5cb7185a9438de28a7b1a7dfe8c01ee7f
diff --git a/tests/resources/revert/.gitted/objects/1f/f0c423042b46cb1d617b81efb715defbe8054d b/tests/resources/revert/.gitted/objects/1f/f0c423042b46cb1d617b81efb715defbe8054d
new file mode 100644
index 000000000..2ed1a2292
--- /dev/null
+++ b/tests/resources/revert/.gitted/objects/1f/f0c423042b46cb1d617b81efb715defbe8054d
diff --git a/tests/resources/revert/.gitted/objects/21/a96a98ed84d45866e1de6e266fd3a61a4ae9dc b/tests/resources/revert/.gitted/objects/21/a96a98ed84d45866e1de6e266fd3a61a4ae9dc
new file mode 100644
index 000000000..95842dbf8
--- /dev/null
+++ b/tests/resources/revert/.gitted/objects/21/a96a98ed84d45866e1de6e266fd3a61a4ae9dc
diff --git a/tests/resources/revert/.gitted/objects/39/9fb3aba3d9d13f7d40a9254ce4402067ef3149 b/tests/resources/revert/.gitted/objects/39/9fb3aba3d9d13f7d40a9254ce4402067ef3149
new file mode 100644
index 000000000..6cb6839d6
--- /dev/null
+++ b/tests/resources/revert/.gitted/objects/39/9fb3aba3d9d13f7d40a9254ce4402067ef3149
@@ -0,0 +1,2 @@
+x
��K!]s
+.��;@b�o�z�A\0m�����<�֞C���,3�d@���_�D�	@�K6ŗ5T�=oS$�T1��.�%@z�Q["-�D	x��]����r�y��<�o]�;�\�	�]��1Y���QE�Ĥ���$l<�,`���aGN�
\ No newline at end of file
diff --git a/tests/resources/revert/.gitted/objects/46/ff0854663aeb2182b9838c8da68e33ac23bc1e b/tests/resources/revert/.gitted/objects/46/ff0854663aeb2182b9838c8da68e33ac23bc1e
new file mode 100644
index 000000000..7064dab52
--- /dev/null
+++ b/tests/resources/revert/.gitted/objects/46/ff0854663aeb2182b9838c8da68e33ac23bc1e
diff --git a/tests/resources/revert/.gitted/objects/5c/f1d643f100d8112834e540264546ba2c159976 b/tests/resources/revert/.gitted/objects/5c/f1d643f100d8112834e540264546ba2c159976
new file mode 100644
index 000000000..dbbf711b5
--- /dev/null
+++ b/tests/resources/revert/.gitted/objects/5c/f1d643f100d8112834e540264546ba2c159976
diff --git a/tests/resources/revert/.gitted/objects/6b/ccd0dc58cea5ccff86014f3d64b31bd8c02a37 b/tests/resources/revert/.gitted/objects/6b/ccd0dc58cea5ccff86014f3d64b31bd8c02a37
new file mode 100644
index 000000000..2664da480
--- /dev/null
+++ b/tests/resources/revert/.gitted/objects/6b/ccd0dc58cea5ccff86014f3d64b31bd8c02a37
diff --git a/tests/resources/revert/.gitted/objects/71/eb9c2b53dbbf3c45fb28b27c850db4b7fb8011 b/tests/resources/revert/.gitted/objects/71/eb9c2b53dbbf3c45fb28b27c850db4b7fb8011
new file mode 100644
index 000000000..995a1e626
--- /dev/null
+++ b/tests/resources/revert/.gitted/objects/71/eb9c2b53dbbf3c45fb28b27c850db4b7fb8011
diff --git a/tests/resources/revert/.gitted/objects/87/59ad453cf01cf7daf14e2a668f8218f9a678eb b/tests/resources/revert/.gitted/objects/87/59ad453cf01cf7daf14e2a668f8218f9a678eb
new file mode 100644
index 000000000..ab19acf83
--- /dev/null
+++ b/tests/resources/revert/.gitted/objects/87/59ad453cf01cf7daf14e2a668f8218f9a678eb
diff --git a/tests/resources/revert/.gitted/objects/9a/95fd974e03c5b93828ceedd28755965b5d5c60 b/tests/resources/revert/.gitted/objects/9a/95fd974e03c5b93828ceedd28755965b5d5c60
new file mode 100644
index 000000000..bb93a34bb
--- /dev/null
+++ b/tests/resources/revert/.gitted/objects/9a/95fd974e03c5b93828ceedd28755965b5d5c60
diff --git a/tests/resources/revert/.gitted/objects/a8/c86221b400b836010567cc3593db6e96c1a83a b/tests/resources/revert/.gitted/objects/a8/c86221b400b836010567cc3593db6e96c1a83a
new file mode 100644
index 000000000..29654616e
--- /dev/null
+++ b/tests/resources/revert/.gitted/objects/a8/c86221b400b836010567cc3593db6e96c1a83a
diff --git a/tests/resources/revert/.gitted/objects/ac/c4d33902092efeb3b714aa0b1007c329e2f2e6 b/tests/resources/revert/.gitted/objects/ac/c4d33902092efeb3b714aa0b1007c329e2f2e6
new file mode 100644
index 000000000..91bb68b41
--- /dev/null
+++ b/tests/resources/revert/.gitted/objects/ac/c4d33902092efeb3b714aa0b1007c329e2f2e6
@@ -0,0 +1,2 @@
+x
��[
+1@Q�JW�
�t�6 F,L��W���8pe��1llU.L��iTB�<dQ�uȉ�#MTI"����v�?O��7ঽ��>dN�0z�"!:�ML�䮽���$�
\ No newline at end of file
diff --git a/tests/resources/revert/.gitted/objects/b6/9d88e177455579896e2be495046e2a51456a9a b/tests/resources/revert/.gitted/objects/b6/9d88e177455579896e2be495046e2a51456a9a
new file mode 100644
index 000000000..a5f69f2c8
--- /dev/null
+++ b/tests/resources/revert/.gitted/objects/b6/9d88e177455579896e2be495046e2a51456a9a
@@ -0,0 +1 @@
+x
��]j!���*.yo�љ{�R��
�l@�NF�ZԴ��$�@�o����	5�4@+z-FP���2{��H�n"�z�Z�R.<��J|�ˀ�����2Ț:V�fR� �´X��a�nc�
>��5��Vs���N��Sh��uC��4Yk����;݇���q�߱
8�Z��F*W�+��B\�ԡ=,�u�w���d�
\ No newline at end of file
diff --git a/tests/resources/revert/.gitted/objects/ca/f99de3a49827117bb66721010eac461b06a80c b/tests/resources/revert/.gitted/objects/ca/f99de3a49827117bb66721010eac461b06a80c
new file mode 100644
index 000000000..7f6f4e0c6
--- /dev/null
+++ b/tests/resources/revert/.gitted/objects/ca/f99de3a49827117bb66721010eac461b06a80c
diff --git a/tests/resources/revert/.gitted/objects/de/03538407ed18914ff05657eeff70425c0f304d b/tests/resources/revert/.gitted/objects/de/03538407ed18914ff05657eeff70425c0f304d
new file mode 100644
index 000000000..e651676fd
--- /dev/null
+++ b/tests/resources/revert/.gitted/objects/de/03538407ed18914ff05657eeff70425c0f304d
@@ -0,0 +1,2 @@
+x
��]J1�}�)�}w�Iw~D|��H:v�l�L��;�|)�������M��PLeY�uY}��ԩ+�mX�2g0�.�{z�,U�5�_�'���!ʂ5i!ag�Ǽ�
��+��ko{����{i����:���3,�u
H1"�#=�N�G�y�ON����
+Z�y2�r�v�h��(Ka�b�d��V[�u��FrR�W�(1��|_c&
\ No newline at end of file
diff --git a/tests/resources/revert/.gitted/objects/e3/4ef1afe54eb526fd92eec66084125f340f1d65 b/tests/resources/revert/.gitted/objects/e3/4ef1afe54eb526fd92eec66084125f340f1d65
new file mode 100644
index 000000000..fc19ebd3d
--- /dev/null
+++ b/tests/resources/revert/.gitted/objects/e3/4ef1afe54eb526fd92eec66084125f340f1d65
diff --git a/tests/resources/revert/.gitted/objects/ea/392a157085bc32daccd59aa1998fe2f5fb9fc0 b/tests/resources/revert/.gitted/objects/ea/392a157085bc32daccd59aa1998fe2f5fb9fc0
new file mode 100644
index 000000000..1451a6ac4
--- /dev/null
+++ b/tests/resources/revert/.gitted/objects/ea/392a157085bc32daccd59aa1998fe2f5fb9fc0
diff --git a/tests/resources/revert/.gitted/objects/ee/c6adcb2f3ceca0cadeccfe01b19382252ece9b b/tests/resources/revert/.gitted/objects/ee/c6adcb2f3ceca0cadeccfe01b19382252ece9b
new file mode 100644
index 000000000..f59f3d48d
--- /dev/null
+++ b/tests/resources/revert/.gitted/objects/ee/c6adcb2f3ceca0cadeccfe01b19382252ece9b
diff --git a/tests/resources/revert/.gitted/refs/heads/master b/tests/resources/revert/.gitted/refs/heads/master
index d3850daa6..180f407e3 100644
--- a/tests/resources/revert/.gitted/refs/heads/master
+++ b/tests/resources/revert/.gitted/refs/heads/master
@@ -1 +1 @@
-2d440f2b3147d3dc7ad1085813478d6d869d5a4d

+2d440f2b3147d3dc7ad1085813478d6d869d5a4d
diff --git a/tests/resources/revert/.gitted/refs/heads/two b/tests/resources/revert/.gitted/refs/heads/two
new file mode 100644
index 000000000..f31ec00e5
--- /dev/null
+++ b/tests/resources/revert/.gitted/refs/heads/two
@@ -0,0 +1 @@
+e34ef1afe54eb526fd92eec66084125f340f1d65
diff --git a/tests/revert/workdir.c b/tests/revert/workdir.c
index 9dc72a9a8..bca1ff926 100644
--- a/tests/revert/workdir.c
+++ b/tests/revert/workdir.c
@@ -137,6 +137,203 @@ void test_revert_workdir__orphan(void)
 	git_commit_free(head);
 }
 
+/*
+ * revert the same commit twice (when the first reverts cleanly):
+ *
+ * git revert 2d440f2
+ * git revert 2d440f2
+ */
+void test_revert_workdir__again(void)
+{
+	git_reference *head_ref;
+	git_commit *orig_head;
+	git_tree *reverted_tree;
+	git_oid reverted_tree_oid, reverted_commit_oid;
+	git_signature *signature;
+
+	struct merge_index_entry merge_index_entries[] = {
+		{ 0100644, "7731926a337c4eaba1e2187d90ebfa0a93659382", 0, "file1.txt" },
+		{ 0100644, "0ab09ea6d4c3634bdf6c221626d8b6f7dd890767", 0, "file2.txt" },
+		{ 0100644, "f4e107c230d08a60fb419d19869f1f282b272d9c", 0, "file3.txt" },
+		{ 0100644, "0f5bfcf58c558d865da6be0281d7795993646cee", 0, "file6.txt" },
+	};
+
+	cl_git_pass(git_repository_head(&head_ref, repo));
+	cl_git_pass(git_reference_peel((git_object **)&orig_head, head_ref, GIT_OBJ_COMMIT));
+	cl_git_pass(git_reset(repo, (git_object *)orig_head, GIT_RESET_HARD));
+
+	cl_git_pass(git_revert(repo, orig_head, NULL));
+
+	cl_assert(merge_test_index(repo_index, merge_index_entries, 4));
+
+	cl_git_pass(git_index_write_tree(&reverted_tree_oid, repo_index));
+	cl_git_pass(git_tree_lookup(&reverted_tree, repo, &reverted_tree_oid));
+
+	cl_git_pass(git_signature_new(&signature, "Reverter", "reverter@example.org", time(NULL), 0));
+	cl_git_pass(git_commit_create(&reverted_commit_oid, repo, "HEAD", signature, signature, NULL, "Reverted!", reverted_tree, 1, (const git_commit **)&orig_head));
+
+	cl_git_pass(git_revert(repo, orig_head, NULL));
+	cl_assert(merge_test_index(repo_index, merge_index_entries, 4));
+
+	git_signature_free(signature);
+	git_tree_free(reverted_tree);
+	git_commit_free(orig_head);
+	git_reference_free(head_ref);
+}
+
+/* git reset --hard 72333f47d4e83616630ff3b0ffe4c0faebcc3c45
+ * git revert --no-commit d1d403d22cbe24592d725f442835cf46fe60c8ac */
+void test_revert_workdir__again_after_automerge(void)
+{
+	git_commit *head, *commit;
+	git_tree *reverted_tree;
+	git_oid head_oid, revert_oid, reverted_tree_oid, reverted_commit_oid;
+	git_signature *signature;
+
+	struct merge_index_entry merge_index_entries[] = {
+		{ 0100644, "caf99de3a49827117bb66721010eac461b06a80c", 0, "file1.txt" },
+		{ 0100644, "0ab09ea6d4c3634bdf6c221626d8b6f7dd890767", 0, "file2.txt" },
+		{ 0100644, "f4e107c230d08a60fb419d19869f1f282b272d9c", 0, "file3.txt" },
+		{ 0100644, "0f5bfcf58c558d865da6be0281d7795993646cee", 0, "file6.txt" },
+	};
+
+	struct merge_index_entry second_revert_entries[] = {
+		{ 0100644, "3a3ef367eaf3fe79effbfb0a56b269c04c2b59fe", 1, "file1.txt" },
+		{ 0100644, "caf99de3a49827117bb66721010eac461b06a80c", 2, "file1.txt" },
+		{ 0100644, "747726e021bc5f44b86de60e3032fd6f9f1b8383", 3, "file1.txt" },
+		{ 0100644, "0ab09ea6d4c3634bdf6c221626d8b6f7dd890767", 0, "file2.txt" },
+		{ 0100644, "f4e107c230d08a60fb419d19869f1f282b272d9c", 0, "file3.txt" },
+		{ 0100644, "0f5bfcf58c558d865da6be0281d7795993646cee", 0, "file6.txt" },
+	};
+
+	git_oid_fromstr(&head_oid, "72333f47d4e83616630ff3b0ffe4c0faebcc3c45");
+	cl_git_pass(git_commit_lookup(&head, repo, &head_oid));
+	cl_git_pass(git_reset(repo, (git_object *)head, GIT_RESET_HARD));
+
+	git_oid_fromstr(&revert_oid, "d1d403d22cbe24592d725f442835cf46fe60c8ac");
+	cl_git_pass(git_commit_lookup(&commit, repo, &revert_oid));
+	cl_git_pass(git_revert(repo, commit, NULL));
+
+	cl_assert(merge_test_index(repo_index, merge_index_entries, 4));
+
+	cl_git_pass(git_index_write_tree(&reverted_tree_oid, repo_index));
+	cl_git_pass(git_tree_lookup(&reverted_tree, repo, &reverted_tree_oid));
+
+	cl_git_pass(git_signature_new(&signature, "Reverter", "reverter@example.org", time(NULL), 0));
+	cl_git_pass(git_commit_create(&reverted_commit_oid, repo, "HEAD", signature, signature, NULL, "Reverted!", reverted_tree, 1, (const git_commit **)&head));
+
+	cl_git_pass(git_revert(repo, commit, NULL));
+	cl_assert(merge_test_index(repo_index, second_revert_entries, 6));
+
+	git_signature_free(signature);
+	git_tree_free(reverted_tree);
+	git_commit_free(commit);
+	git_commit_free(head);
+}
+
+/*
+ * revert the same commit twice (when the first reverts cleanly):
+ *
+ * git revert 2d440f2
+ * git revert 2d440f2
+ */
+void test_revert_workdir__again_after_edit(void)
+{
+	git_reference *head_ref;
+	git_commit *orig_head, *commit;
+	git_tree *reverted_tree;
+	git_oid orig_head_oid, revert_oid, reverted_tree_oid, reverted_commit_oid;
+	git_signature *signature;
+
+	struct merge_index_entry merge_index_entries[] = {
+		{ 0100644, "3721552e06c4bdc7d478e0674e6304888545d5fd", 0, "file1.txt" },
+		{ 0100644, "0ab09ea6d4c3634bdf6c221626d8b6f7dd890767", 0, "file2.txt" },
+		{ 0100644, "f4e107c230d08a60fb419d19869f1f282b272d9c", 0, "file3.txt" },
+		{ 0100644, "0f5bfcf58c558d865da6be0281d7795993646cee", 0, "file6.txt" },
+	};
+
+	cl_git_pass(git_repository_head(&head_ref, repo));
+
+	cl_git_pass(git_oid_fromstr(&orig_head_oid, "399fb3aba3d9d13f7d40a9254ce4402067ef3149"));
+	cl_git_pass(git_commit_lookup(&orig_head, repo, &orig_head_oid));
+	cl_git_pass(git_reset(repo, (git_object *)orig_head, GIT_RESET_HARD));
+
+	cl_git_pass(git_oid_fromstr(&revert_oid, "2d440f2b3147d3dc7ad1085813478d6d869d5a4d"));
+	cl_git_pass(git_commit_lookup(&commit, repo, &revert_oid));
+
+	cl_git_pass(git_revert(repo, commit, NULL));
+
+	cl_assert(merge_test_index(repo_index, merge_index_entries, 4));
+
+	cl_git_pass(git_index_write_tree(&reverted_tree_oid, repo_index));
+	cl_git_pass(git_tree_lookup(&reverted_tree, repo, &reverted_tree_oid));
+
+	cl_git_pass(git_signature_new(&signature, "Reverter", "reverter@example.org", time(NULL), 0));
+	cl_git_pass(git_commit_create(&reverted_commit_oid, repo, "HEAD", signature, signature, NULL, "Reverted!", reverted_tree, 1, (const git_commit **)&orig_head));
+
+	cl_git_pass(git_revert(repo, commit, NULL));
+	cl_assert(merge_test_index(repo_index, merge_index_entries, 4));
+
+	git_signature_free(signature);
+	git_tree_free(reverted_tree);
+	git_commit_free(commit);
+	git_commit_free(orig_head);
+	git_reference_free(head_ref);
+}
+
+/*
+ * revert the same commit twice (when the first reverts cleanly):
+ *
+ * git reset --hard e34ef1a
+ * git revert 71eb9c2
+ */
+void test_revert_workdir__again_after_edit_two(void)
+{
+	git_buf diff_buf = GIT_BUF_INIT;
+	git_config *config;
+	git_oid head_commit_oid, revert_commit_oid;
+	git_commit *head_commit, *revert_commit;
+
+	struct merge_index_entry merge_index_entries[] = {
+		{ 0100644, "1ff0c423042b46cb1d617b81efb715defbe8054d", 0, ".gitattributes" },
+		{ 0100644, "1bc915c5cb7185a9438de28a7b1a7dfe8c01ee7f", 0, ".gitignore" },
+		{ 0100644, "a8c86221b400b836010567cc3593db6e96c1a83a", 1, "file.txt" },
+		{ 0100644, "46ff0854663aeb2182b9838c8da68e33ac23bc1e", 2, "file.txt" },
+		{ 0100644, "21a96a98ed84d45866e1de6e266fd3a61a4ae9dc", 3, "file.txt" },
+	};
+
+	cl_git_pass(git_repository_config(&config, repo));
+	cl_git_pass(git_config_set_bool(config, "core.autocrlf", 0));
+
+	cl_git_pass(git_oid_fromstr(&head_commit_oid, "e34ef1afe54eb526fd92eec66084125f340f1d65"));
+	cl_git_pass(git_commit_lookup(&head_commit, repo, &head_commit_oid));
+	cl_git_pass(git_reset(repo, (git_object *)head_commit, GIT_RESET_HARD));
+
+	cl_git_pass(git_oid_fromstr(&revert_commit_oid, "71eb9c2b53dbbf3c45fb28b27c850db4b7fb8011"));
+	cl_git_pass(git_commit_lookup(&revert_commit, repo, &revert_commit_oid));
+
+	cl_git_pass(git_revert(repo, revert_commit, NULL));
+
+	cl_assert(merge_test_index(repo_index, merge_index_entries, 5));
+
+	cl_git_pass(git_futils_readbuffer(&diff_buf, "revert/file.txt"));
+	cl_assert(strcmp(diff_buf.ptr,	"a\n" \
+		"<<<<<<< HEAD\n" \
+		"=======\n" \
+		"a\n" \
+		">>>>>>> parent of 71eb9c2... revert me\n" \
+		"a\n" \
+		"a\n" \
+		"a\n" \
+		"a\n" \
+		"ab\n") == 0);
+
+	git_commit_free(revert_commit);
+	git_commit_free(head_commit);
+	git_config_free(config);
+	git_buf_free(&diff_buf);
+}
+
 /* git reset --hard 72333f47d4e83616630ff3b0ffe4c0faebcc3c45
  * git revert --no-commit d1d403d22cbe24592d725f442835cf46fe60c8ac */
 void test_revert_workdir__conflict_use_ours(void)
@@ -161,7 +358,7 @@ void test_revert_workdir__conflict_use_ours(void)
 		{ 0100644, "0f5bfcf58c558d865da6be0281d7795993646cee", 0, "file6.txt" },
 	};
 
-	opts.merge_tree_opts.automerge_flags = GIT_MERGE_AUTOMERGE_NONE;
+	opts.merge_tree_opts.file_favor = GIT_MERGE_FILE_FAVOR_NO_MERGE;
 	opts.checkout_opts.checkout_strategy = GIT_CHECKOUT_SAFE | GIT_CHECKOUT_USE_OURS;
 
 	git_oid_fromstr(&head_oid, "72333f47d4e83616630ff3b0ffe4c0faebcc3c45");