Subject: [PATCH v5] merge-tree: add -X strategy option

From: "Izzy via GitGitGadget" <[email-masked]>
Date: Sat, 16 Sep 2023 08:37:17 +0000

From: Tang Yuyi <[email-masked]>

Add merge strategy option to produce more customizable merge result such
as automatically resolving conflicts.

Signed-off-by: Tang Yuyi <[email-masked]>
---
    merge-tree: add -X strategy option
    
    Change-Id: I16be592262d13cebcff8726eb043f7ecdb313b76

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1565%2FWingT%2Fmerge_tree_allow_strategy_option-v5
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1565/WingT/merge_tree_allow_strategy_option-v5
Pull-Request: https://github.com/gitgitgadget/git/pull/1565

Range-diff vs v4:

 1:  d2d8fcc2e9b ! 1:  28d4282e0d8 merge-tree: add -X strategy option
     @@ Commit message
      
       ## builtin/merge-tree.c ##
      @@
     + #include "quote.h"
       #include "tree.h"
       #include "config.h"
     ++#include "strvec.h"
       
     -+static const char **xopts;
     -+static size_t xopts_nr, xopts_alloc;
       static int line_termination = '\n';
       
     - struct merge_list {
      @@ builtin/merge-tree.c: struct merge_tree_options {
       	int show_messages;
       	int name_only;
     @@ builtin/merge-tree.c: static int real_merge(struct merge_tree_options *o,
       
       	opt.branch1 = branch1;
      @@ builtin/merge-tree.c: static int real_merge(struct merge_tree_options *o,
     - 	return !result.clean; /* result.clean < 0 handled above */
     - }
     - 
     -+static int option_parse_x(const struct option *opt,
     -+			  const char *arg, int unset)
     -+{
     -+	if (unset)
     -+		return 0;
     -+
     -+	ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
     -+	xopts[xopts_nr++] = xstrdup(arg);
     -+	return 0;
     -+}
     -+
       int cmd_merge_tree(int argc, const char **argv, const char *prefix)
       {
       	struct merge_tree_options o = { .show_messages = -1 };
     ++	struct strvec xopts = STRVEC_INIT;
     + 	int expected_remaining_argc;
     + 	int original_argc;
     + 	const char *merge_base = NULL;
      @@ builtin/merge-tree.c: int cmd_merge_tree(int argc, const char **argv, const char *prefix)
       			   &merge_base,
       			   N_("commit"),
       			   N_("specify a merge-base for the merge")),
     -+		OPT_CALLBACK('X', "strategy-option", &xopts,
     -+			N_("option=value"),
     -+			N_("option for selected merge strategy"),
     -+			option_parse_x),
     ++		OPT_STRVEC('X', "strategy-option", &xopts, N_("option=value"),
     ++			N_("option for selected merge strategy")),
       		OPT_END()
       	};
       
     @@ builtin/merge-tree.c: int cmd_merge_tree(int argc, const char **argv, const char
       	argc = parse_options(argc, argv, prefix, mt_options,
       			     merge_tree_usage, PARSE_OPT_STOP_AT_NON_OPTION);
       
     -+	for (int x = 0; x < xopts_nr; x++)
     -+		if (parse_merge_opt(&o.merge_options, xopts[x]))
     -+			die(_("unknown strategy option: -X%s"), xopts[x]);
     ++	for (int x = 0; x < xopts.nr; x++)
     ++		if (parse_merge_opt(&o.merge_options, xopts.v[x]))
     ++			die(_("unknown strategy option: -X%s"), xopts.v[x]);
      +
       	/* Handle --stdin */
       	if (o.use_stdin) {
     @@ t/t4301-merge-tree-write-tree.sh: test_expect_success 'Content merge and a few c
      +	git merge --abort &&
      +
      +	git merge -X ours side4 &&
     -+	git rev-parse HEAD^{tree} > expected &&
     ++	git rev-parse HEAD^{tree} >expected &&
      +
     -+    git merge-tree -X ours side1 side4 > actual &&
     ++	git merge-tree -X ours side1 side4 >actual &&
      +
      +	test_cmp expected actual
      +'

 builtin/merge-tree.c             | 11 +++++++++++
 t/t4301-merge-tree-write-tree.sh | 23 +++++++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/builtin/merge-tree.c b/builtin/merge-tree.c
index 0de42aecf4b..97d0fe6c952 100644
--- a/builtin/merge-tree.c
+++ b/builtin/merge-tree.c
@@ -18,6 +18,7 @@
 #include "quote.h"
 #include "tree.h"
 #include "config.h"
+#include "strvec.h"
 
 static int line_termination = '\n';
 
@@ -414,6 +415,7 @@ struct merge_tree_options {
 	int show_messages;
 	int name_only;
 	int use_stdin;
+	struct merge_options merge_options;
 };
 
 static int real_merge(struct merge_tree_options *o,
@@ -439,6 +441,8 @@ static int real_merge(struct merge_tree_options *o,
 
 	init_merge_options(&opt, the_repository);
 
+	opt.recursive_variant = o->merge_options.recursive_variant;
+
 	opt.show_rename_progress = 0;
 
 	opt.branch1 = branch1;
@@ -513,6 +517,7 @@ static int real_merge(struct merge_tree_options *o,
 int cmd_merge_tree(int argc, const char **argv, const char *prefix)
 {
 	struct merge_tree_options o = { .show_messages = -1 };
+	struct strvec xopts = STRVEC_INIT;
 	int expected_remaining_argc;
 	int original_argc;
 	const char *merge_base = NULL;
@@ -548,6 +553,8 @@ int cmd_merge_tree(int argc, const char **argv, const char *prefix)
 			   &merge_base,
 			   N_("commit"),
 			   N_("specify a merge-base for the merge")),
+		OPT_STRVEC('X', "strategy-option", &xopts, N_("option=value"),
+			N_("option for selected merge strategy")),
 		OPT_END()
 	};
 
@@ -556,6 +563,10 @@ int cmd_merge_tree(int argc, const char **argv, const char *prefix)
 	argc = parse_options(argc, argv, prefix, mt_options,
 			     merge_tree_usage, PARSE_OPT_STOP_AT_NON_OPTION);
 
+	for (int x = 0; x < xopts.nr; x++)
+		if (parse_merge_opt(&o.merge_options, xopts.v[x]))
+			die(_("unknown strategy option: -X%s"), xopts.v[x]);
+
 	/* Handle --stdin */
 	if (o.use_stdin) {
 		struct strbuf buf = STRBUF_INIT;
diff --git a/t/t4301-merge-tree-write-tree.sh b/t/t4301-merge-tree-write-tree.sh
index 250f721795b..b2c8a43fce3 100755
--- a/t/t4301-merge-tree-write-tree.sh
+++ b/t/t4301-merge-tree-write-tree.sh
@@ -22,6 +22,7 @@ test_expect_success setup '
 	git branch side1 &&
 	git branch side2 &&
 	git branch side3 &&
+	git branch side4 &&
 
 	git checkout side1 &&
 	test_write_lines 1 2 3 4 5 6 >numbers &&
@@ -46,6 +47,13 @@ test_expect_success setup '
 	test_tick &&
 	git commit -m rename-numbers &&
 
+	git checkout side4 &&
+	test_write_lines 0 1 2 3 4 5 >numbers &&
+	echo yo >greeting &&
+	git add numbers greeting &&
+	test_tick &&
+	git commit -m other-content-modifications &&
+
 	git switch --orphan unrelated &&
 	>something-else &&
 	git add something-else &&
@@ -97,6 +105,21 @@ test_expect_success 'Content merge and a few conflicts' '
 	test_cmp expect actual
 '
 
+test_expect_success 'Auto resolve conflicts by "ours" strategy option' '
+	git checkout side1^0 &&
+
+	# make sure merge conflict exists
+	test_must_fail git merge side4 &&
+	git merge --abort &&
+
+	git merge -X ours side4 &&
+	git rev-parse HEAD^{tree} >expected &&
+
+	git merge-tree -X ours side1 side4 >actual &&
+
+	test_cmp expected actual
+'
+
 test_expect_success 'Barf on misspelled option, with exit code other than 0 or 1' '
 	# Mis-spell with single "s" instead of double "s"
 	test_expect_code 129 git merge-tree --write-tree --mesages FOOBAR side1 side2 2>expect &&

base-commit: ac83bc5054c2ac489166072334b4147ce6d0fccb
-- 
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