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[PATCH v2 07/10] evolve: implement the git change command

From
SGStefan Xenos via GitGitGadget <gitgitgadget@gmail.com>
Date
Oct 5, 2022, 14:59 UTC
Message-ID
<f7a90700e0e79b3ae6fbc5cf32723da04e907347.1664981958.git.gitgitgadget@gmail.com>
In-Reply-To
<pull.1356.v2.git.1664981957.gitgitgadget@gmail.com>
From: Stefan Xenos <sxenos@google.com>

Implement the git change update command, which are sufficient for constructing change graphs.

For example, to create a new change (a stable name) that refers to HEAD:
git change update -c HEAD
To record a rebase or amend in the change graph:
git change update -c <new_commit> -r <old_commit>
To record a cherry-pick in the change graph:
git change update -c <new_commit> -o <original_commit>
Signed-off-by: Stefan Xenos <sxenos@google.com>
Signed-off-by: Chris Poucet <poucet@google.com>
---
 .gitignore       |   1 +
 Makefile         |   1 +
 builtin.h        |   1 +
 builtin/change.c | 253 +++++++++++++++++++++++++++++++++++++++++++++++
 git.c            |   1 +
 ref-filter.c     |   2 +-
 ref-filter.h     |   4 +
 7 files changed, 262 insertions(+), 1 deletion(-)
 create mode 100644 builtin/change.c
diff --git a/.gitignore b/.gitignore
index b3dcafcb331..a57fd8d8897 100644
--- a/.gitignore
+++ b/.gitignore
@@ -28,6 +28,7 @@
 /git-bugreport
 /git-bundle
 /git-cat-file
+/git-change
 /git-check-attr
 /git-check-ignore
 /git-check-mailmap
diff --git a/Makefile b/Makefile
index 68082ef94c7..82f68f13d9f 100644
--- a/Makefile
+++ b/Makefile
@@ -1142,6 +1142,7 @@ BUILTIN_OBJS += builtin/branch.o
 BUILTIN_OBJS += builtin/bugreport.o
 BUILTIN_OBJS += builtin/bundle.o
 BUILTIN_OBJS += builtin/cat-file.o
+BUILTIN_OBJS += builtin/change.o
 BUILTIN_OBJS += builtin/check-attr.o
 BUILTIN_OBJS += builtin/check-ignore.o
 BUILTIN_OBJS += builtin/check-mailmap.o
diff --git a/builtin.h b/builtin.h
index 8901a34d6bf..c10f20c972c 100644
--- a/builtin.h
+++ b/builtin.h
@@ -122,6 +122,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix);
 int cmd_bugreport(int argc, const char **argv, const char *prefix);
 int cmd_bundle(int argc, const char **argv, const char *prefix);
 int cmd_cat_file(int argc, const char **argv, const char *prefix);
+int cmd_change(int argc, const char **argv, const char *prefix);
 int cmd_checkout(int argc, const char **argv, const char *prefix);
 int cmd_checkout__worker(int argc, const char **argv, const char *prefix);
 int cmd_checkout_index(int argc, const char **argv, const char *prefix);
diff --git a/builtin/change.c b/builtin/change.c
new file mode 100644
index 00000000000..e4e8e15b768
--- /dev/null
+++ b/builtin/change.c
@@ -0,0 +1,253 @@
+#include "builtin.h"
+#include "ref-filter.h"
+#include "parse-options.h"
+#include "metacommit.h"
+#include "config.h"
+
+static const char * const builtin_change_usage[] = {
+	N_("git change list [<pattern>...]"),
+	N_("git change update [--force] [--replace <treeish>...] "
+	   "[--origin <treeish>...] [--content <newtreeish>]"),
+	NULL
+};
+
+static const char * const builtin_list_usage[] = {
+	N_("git change list [<pattern>...]"),
+	NULL
+};
+
+static const char * const builtin_update_usage[] = {
+	N_("git change update [--force] [--replace <treeish>...] "
+	"[--origin <treeish>...] [--content <newtreeish>]"),
+	NULL
+};
+
+static int change_list(int argc, const char **argv, const char* prefix)
+{
+	struct option options[] = {
+		OPT_END()
+	};
+	struct ref_filter filter = { 0 };
+	struct ref_sorting *sorting;
+	struct string_list sorting_options = STRING_LIST_INIT_DUP;
+	struct ref_format format = REF_FORMAT_INIT;
+	struct ref_array array = { 0 };
+	size_t i;
+
+	argc = parse_options(argc, argv, prefix, options, builtin_list_usage, 0);
+
+	setup_ref_filter_porcelain_msg();
+
+	filter.kind = FILTER_REFS_CHANGES;
+	filter.name_patterns = argv;
+
+	filter_refs(&array, &filter, FILTER_REFS_CHANGES);
+
+	/* TODO: This causes a crash. It sets one of the atom_value handlers to
+	 * something invalid, which causes a crash later when we call
+	 * show_ref_array_item. Figure out why this happens and put back the sorting.
+	 *
+	 * sorting = ref_sorting_options(&sorting_options);
+	 * ref_array_sort(sorting, &array); */
+
+	if (!format.format)
+		format.format = "%(refname:lstrip=1)";
+
+	if (verify_ref_format(&format))
+		die(_("unable to parse format string"));
+
+	sorting = ref_sorting_options(&sorting_options);
+	ref_array_sort(sorting, &array);
+
+
+	for (i = 0; i < array.nr; i++) {
+		struct strbuf output = STRBUF_INIT;
+		struct strbuf err = STRBUF_INIT;
+		if (format_ref_array_item(array.items[i], &format, &output, &err))
+			die("%s", err.buf);
+		fwrite(output.buf, 1, output.len, stdout);
+		putchar('\n');
+
+		strbuf_release(&err);
+		strbuf_release(&output);
+	}
+
+	ref_array_clear(&array);
+	ref_sorting_release(sorting);
+
+	return 0;
+}
+
+struct update_state {
+	int options;
+	const char* change;
+	const char* content;
+	struct string_list replace;
+	struct string_list origin;
+};
+
+#define UPDATE_STATE_INIT { \
+	.content = "HEAD", \
+	.replace = STRING_LIST_INIT_NODUP, \
+	.origin = STRING_LIST_INIT_NODUP \
+}
+
+static void clear_update_state(struct update_state *state)
+{
+	string_list_clear(&state->replace, 0);
+	string_list_clear(&state->origin, 0);
+}
+
+static int update_option_parse_replace(const struct option *opt,
+				       const char *arg, int unset)
+{
+	struct update_state *state = opt->value;
+	string_list_append(&state->replace, arg);
+	return 0;
+}
+
+static int update_option_parse_origin(const struct option *opt,
+				      const char *arg, int unset)
+{
+	struct update_state *state = opt->value;
+	string_list_append(&state->origin, arg);
+	return 0;
+}
+
+static int resolve_commit(const char *committish, struct object_id *result)
+{
+	struct commit *commit;
+	if (get_oid_committish(committish, result))
+		die(_("failed to resolve '%s' as a valid revision."), committish);
+	commit = lookup_commit_reference(the_repository, result);
+	if (!commit)
+		die(_("could not parse object '%s'."), committish);
+	oidcpy(result, &commit->object.oid);
+	return 0;
+}
+
+static void resolve_commit_list(const struct string_list *commitsish_list,
+	struct oid_array* result)
+{
+	struct string_list_item *item;
+
+	for_each_string_list_item(item, commitsish_list) {
+		struct object_id next;
+		resolve_commit(item->string, &next);
+		oid_array_append(result, &next);
+	}
+}
+
+/*
+ * Given the command-line options for the update command, fills in a
+ * metacommit_data with the corresponding changes.
+ */
+static void get_metacommit_from_command_line(
+	const struct update_state* commands, struct metacommit_data *result)
+{
+	resolve_commit(commands->content, &(result->content));
+	resolve_commit_list(&(commands->replace), &(result->replace));
+	resolve_commit_list(&(commands->origin), &(result->origin));
+}
+
+static int perform_update(
+	struct repository *repo,
+	const struct update_state *state,
+	struct strbuf *err)
+{
+	struct metacommit_data metacommit = METACOMMIT_DATA_INIT;
+	struct string_list changes = STRING_LIST_INIT_DUP;
+	int ret;
+	struct string_list_item *item;
+
+	get_metacommit_from_command_line(state, &metacommit);
+
+	ret = record_metacommit(
+		repo,
+		&metacommit,
+		state->change,
+		state->options,
+		err,
+		&changes);
+
+	for_each_string_list_item(item, &changes) {
+
+		const char* name = lstrip_ref_components(item->string, 1);
+		if (!name)
+			die(_("failed to remove `refs/` from %s"), item->string);
+
+		if (item->util)
+			fprintf(stdout, _("Updated change %s"), name);
+		else
+			fprintf(stdout, _("Created change %s"), name);
+		putchar('\n');
+	}
+
+	string_list_clear(&changes, 0);
+	clear_metacommit_data(&metacommit);
+
+	return ret;
+}
+
+static int change_update(int argc, const char **argv, const char* prefix)
+{
+	int result;
+	struct strbuf err = STRBUF_INIT;
+	struct update_state state = UPDATE_STATE_INIT;
+	struct option options[] = {
+		{ OPTION_CALLBACK, 'r', "replace", &state, N_("commit"),
+			N_("marks the given commit as being obsolete"),
+			0, update_option_parse_replace },
+		{ OPTION_CALLBACK, 'o', "origin", &state, N_("commit"),
+			N_("marks the given commit as being the origin of this commit"),
+			0, update_option_parse_origin },
+
+		OPT_STRING('c', "content", &state.content, N_("commit"),
+				 N_("identifies the new content commit for the change")),
+		OPT_STRING('g', "change", &state.change, N_("commit"),
+				 N_("name of the change to update")),
+		OPT_SET_INT_F('n', "new", &state.options,
+			      N_("create a new change - do not append to any existing change"),
+			      UPDATE_OPTION_NOAPPEND, 0),
+		OPT_SET_INT_F('F', "force", &state.options,
+			      N_("overwrite an existing change of the same name"),
+			      UPDATE_OPTION_FORCE, 0),
+		OPT_END()
+	};
+
+	argc = parse_options(argc, argv, prefix, options, builtin_update_usage, 0);
+	result = perform_update(the_repository, &state, &err);
+
+	if (result < 0) {
+		error("%s", err.buf);
+		strbuf_release(&err);
+	}
+
+	clear_update_state(&state);
+
+	return result;
+}
+
+int cmd_change(int argc, const char **argv, const char *prefix)
+{
+	parse_opt_subcommand_fn *fn = NULL;
+	/* No options permitted before subcommand currently */
+	struct option options[] = {
+		OPT_SUBCOMMAND("list", &fn, change_list),
+		OPT_SUBCOMMAND("update", &fn, change_update),
+		OPT_END()
+	};
+
+	argc = parse_options(argc, argv, prefix, options, builtin_change_usage,
+		PARSE_OPT_SUBCOMMAND_OPTIONAL);
+
+	if (!fn) {
+		if (argc) {
+			error(_("unknown subcommand: `%s'"), argv[0]);
+			usage_with_options(builtin_change_usage, options);
+		}
+		fn = change_list;
+	}
+
+	return !!fn(argc, argv, prefix);
+}
diff --git a/git.c b/git.c
index da411c53822..837b1abc53b 100644
--- a/git.c
+++ b/git.c
@@ -498,6 +498,7 @@ static struct cmd_struct commands[] = {
 	{ "bugreport", cmd_bugreport, RUN_SETUP_GENTLY },
 	{ "bundle", cmd_bundle, RUN_SETUP_GENTLY },
 	{ "cat-file", cmd_cat_file, RUN_SETUP },
+	{ "change", cmd_change, RUN_SETUP},
 	{ "check-attr", cmd_check_attr, RUN_SETUP },
 	{ "check-ignore", cmd_check_ignore, RUN_SETUP | NEED_WORK_TREE },
 	{ "check-mailmap", cmd_check_mailmap, RUN_SETUP },
diff --git a/ref-filter.c b/ref-filter.c
index 6a1789c623f..2d7a919d547 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -1557,7 +1557,7 @@ static inline char *copy_advance(char *dst, const char *src)
 	return dst;
 }
 
-static const char *lstrip_ref_components(const char *refname, int len)
+const char *lstrip_ref_components(const char *refname, int len)
 {
 	long remaining = len;
 	const char *start = xstrdup(refname);
diff --git a/ref-filter.h b/ref-filter.h
index db3ee44e4dc..193700694ad 100644
--- a/ref-filter.h
+++ b/ref-filter.h
@@ -145,4 +145,8 @@ struct ref_array_item *ref_array_push(struct ref_array *array,
 				      const char *refname,
 				      const struct object_id *oid);
 
+/* Strips `len` prefix components from the refname. */
+const char *lstrip_ref_components(const char *refname, int len);
+
+
 #endif /*  REF_FILTER_H  */

-- 
gitgitgadget
Previous: Phillip WoodNext: Chris Poucet via GitGitGadget
Message 62 of 66 in “Add the Git Change command”
  1. 00/10 Add the Git Change commandChristophe Poucet via GitGitGadget, Sep 23, 2022
  2. 02/10 sha1-array: implement oid_array_readonly_containsChris Poucet via GitGitGadget, Sep 23, 2022
  3. Phillip WoodSep 26, 2022
  4. 03/10 ref-filter: add the metas namespace to ref-filterChris Poucet via GitGitGadget, Sep 23, 2022
  5. Phillip WoodSep 26, 2022
  6. Chris POct 4, 2022
  7. 04/10 evolve: add support for parsing metacommitsStefan Xenos via GitGitGadget, Sep 23, 2022
  8. Phillip WoodSep 26, 2022
  9. Chris POct 4, 2022
  10. Phillip WoodOct 4, 2022
  11. 01/10 technical doc: add a design doc for the evolve commandStefan Xenos via GitGitGadget, Sep 23, 2022
  12. Jerry ZhangSep 23, 2022
  13. Junio C HamanoSep 28, 2022
  14. Junio C HamanoSep 28, 2022
  15. Phillip WoodSep 29, 2022
  16. Jonathan TanSep 29, 2022
  17. 05/10 evolve: add the change-table structureStefan Xenos via GitGitGadget, Sep 23, 2022
  18. Phillip WoodSep 27, 2022
  19. Ævar Arnfjörð BjarmasonSep 27, 2022
  20. Phillip WoodSep 27, 2022
  21. Ævar Arnfjörð BjarmasonSep 27, 2022
  22. Phillip WoodSep 28, 2022
  23. Ævar Arnfjörð BjarmasonSep 28, 2022
  24. Junio C HamanoSep 28, 2022
  25. Phillip WoodSep 27, 2022
  26. Chris POct 4, 2022
  27. 06/10 evolve: add support for writing metacommitsStefan Xenos via GitGitGadget, Sep 23, 2022
  28. Phillip WoodSep 28, 2022
  29. Chris POct 5, 2022
  30. Phillip WoodOct 5, 2022
  31. 10/10 evolve: add documentation for `git change`Chris Poucet via GitGitGadget, Sep 23, 2022
  32. Phillip WoodSep 25, 2022
  33. 07/10 evolve: implement the git change commandStefan Xenos via GitGitGadget, Sep 23, 2022
  34. Phillip WoodSep 25, 2022
  35. Ævar Arnfjörð BjarmasonSep 26, 2022
  36. Ævar Arnfjörð BjarmasonSep 26, 2022
  37. Chris POct 5, 2022
  38. 09/10 evolve: add delete commandChris Poucet via GitGitGadget, Sep 23, 2022
  39. Ævar Arnfjörð BjarmasonSep 26, 2022
  40. Chris PoucetSep 26, 2022
  41. 08/10 evolve: add the git change list commandStefan Xenos via GitGitGadget, Sep 23, 2022
  42. Phillip WoodSep 25, 2022
  43. Chris POct 4, 2022
  44. Phillip WoodOct 4, 2022
  45. Chris POct 4, 2022
  46. Chris POct 4, 2022
  47. Phillip WoodOct 4, 2022
  48. Phillip WoodOct 4, 2022
  49. 00/10 RFC: Git Evolve / ChangeChristophe Poucet via GitGitGadget, Oct 5, 2022
  50. 03/10 ref-filter: add the metas namespace to ref-filterChris Poucet via GitGitGadget, Oct 5, 2022
  51. 02/10 sha1-array: implement oid_array_readonly_containsChris Poucet via GitGitGadget, Oct 5, 2022
  52. 05/10 evolve: add the change-table structureStefan Xenos via GitGitGadget, Oct 5, 2022
  53. 04/10 evolve: add support for parsing metacommitsStefan Xenos via GitGitGadget, Oct 5, 2022
  54. 06/10 evolve: add support for writing metacommitsStefan Xenos via GitGitGadget, Oct 5, 2022
  55. 01/10 technical doc: add a design doc for the evolve commandStefan Xenos via GitGitGadget, Oct 5, 2022
  56. Chris PoucetOct 5, 2022
  57. Glen ChooOct 6, 2022
  58. Victoria DyeOct 10, 2022
  59. Phillip WoodOct 11, 2022
  60. Victoria DyeOct 11, 2022
  61. Phillip WoodOct 12, 2022
  62. 07/10 evolve: implement the git change commandStefan Xenos via GitGitGadget, Oct 5, 2022
  63. 09/10 evolve: add documentation for `git change`Chris Poucet via GitGitGadget, Oct 5, 2022
  64. 08/10 evolve: add delete commandChris Poucet via GitGitGadget, Oct 5, 2022
  65. 10/10 evolve: add tests for the git-change commandChris Poucet via GitGitGadget, Oct 5, 2022
  66. Phillip WoodOct 10, 2022

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