reftable: remove name checks

In the preceding commit we have disabled name checks in the "reftable"
backend. These checks were responsible for verifying multiple things
when writing records to the reftable stack:

  - Detecting file/directory conflicts. Starting with the preceding
    commits this is now handled by the reftable backend itself via
    `refs_verify_refname_available()`.

  - Validating refnames. This is handled by `check_refname_format()` in
    the generic ref transacton layer.

The code in the reftable library is thus not used anymore and likely to
bitrot over time. Remove it.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

12 files changed, 1 insertions, 462 deletions

diff --git a/Makefile b/Makefile
index c43c1bd1a0..05e3d37581 100644
--- a/Makefile
+++ b/Makefile
@@ -2655,7 +2655,6 @@ REFTABLE_OBJS += reftable/merged.o
 REFTABLE_OBJS += reftable/pq.o
 REFTABLE_OBJS += reftable/reader.o
 REFTABLE_OBJS += reftable/record.o
-REFTABLE_OBJS += reftable/refname.o
 REFTABLE_OBJS += reftable/generic.o
 REFTABLE_OBJS += reftable/stack.o
 REFTABLE_OBJS += reftable/tree.o
@@ -2668,7 +2667,6 @@ REFTABLE_TEST_OBJS += reftable/merged_test.o
 REFTABLE_TEST_OBJS += reftable/pq_test.o
 REFTABLE_TEST_OBJS += reftable/record_test.o
 REFTABLE_TEST_OBJS += reftable/readwrite_test.o
-REFTABLE_TEST_OBJS += reftable/refname_test.o
 REFTABLE_TEST_OBJS += reftable/stack_test.o
 REFTABLE_TEST_OBJS += reftable/test_framework.o
 REFTABLE_TEST_OBJS += reftable/tree_test.o
diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c
index 7515dd3019..8a54b0d8b2 100644
--- a/refs/reftable-backend.c
+++ b/refs/reftable-backend.c
@@ -247,11 +247,6 @@ static struct ref_store *reftable_be_init(struct repository *repo,
 	refs->write_options.block_size = 4096;
 	refs->write_options.hash_id = repo->hash_algo->format_id;
 	refs->write_options.default_permissions = calc_shared_perm(0666 & ~mask);
-	/*
-	 * We verify names via `refs_verify_refname_available()`, so there is
-	 * no need to do the same checks in the reftable library again.
-	 */
-	refs->write_options.skip_name_check = 1;
 
 	/*
 	 * Set up the main reftable stack that is hosted in GIT_COMMON_DIR.
diff --git a/reftable/error.c b/reftable/error.c
index 0d1766735e..169f89d2f1 100644
--- a/reftable/error.c
+++ b/reftable/error.c
@@ -27,8 +27,6 @@ const char *reftable_error_str(int err)
 		return "misuse of the reftable API";
 	case REFTABLE_ZLIB_ERROR:
 		return "zlib failure";
-	case REFTABLE_NAME_CONFLICT:
-		return "file/directory conflict";
 	case REFTABLE_EMPTY_TABLE_ERROR:
 		return "wrote empty table";
 	case REFTABLE_REFNAME_ERROR:
diff --git a/reftable/refname.c b/reftable/refname.c
deleted file mode 100644
index 7570e4acf9..0000000000
--- a/reftable/refname.c
+++ /dev/null
@@ -1,209 +0,0 @@
-/*
-  Copyright 2020 Google LLC
-
-  Use of this source code is governed by a BSD-style
-  license that can be found in the LICENSE file or at
-  https://developers.google.com/open-source/licenses/bsd
-*/
-
-#include "system.h"
-#include "reftable-error.h"
-#include "basics.h"
-#include "refname.h"
-#include "reftable-iterator.h"
-
-struct find_arg {
-	char **names;
-	const char *want;
-};
-
-static int find_name(size_t k, void *arg)
-{
-	struct find_arg *f_arg = arg;
-	return strcmp(f_arg->names[k], f_arg->want) >= 0;
-}
-
-static int modification_has_ref(struct modification *mod, const char *name)
-{
-	struct reftable_ref_record ref = { NULL };
-	int err = 0;
-
-	if (mod->add_len > 0) {
-		struct find_arg arg = {
-			.names = mod->add,
-			.want = name,
-		};
-		int idx = binsearch(mod->add_len, find_name, &arg);
-		if (idx < mod->add_len && !strcmp(mod->add[idx], name)) {
-			return 0;
-		}
-	}
-
-	if (mod->del_len > 0) {
-		struct find_arg arg = {
-			.names = mod->del,
-			.want = name,
-		};
-		int idx = binsearch(mod->del_len, find_name, &arg);
-		if (idx < mod->del_len && !strcmp(mod->del[idx], name)) {
-			return 1;
-		}
-	}
-
-	err = reftable_table_read_ref(&mod->tab, name, &ref);
-	reftable_ref_record_release(&ref);
-	return err;
-}
-
-static void modification_release(struct modification *mod)
-{
-	/* don't delete the strings themselves; they're owned by ref records.
-	 */
-	FREE_AND_NULL(mod->add);
-	FREE_AND_NULL(mod->del);
-	mod->add_len = 0;
-	mod->del_len = 0;
-}
-
-static int modification_has_ref_with_prefix(struct modification *mod,
-					    const char *prefix)
-{
-	struct reftable_iterator it = { NULL };
-	struct reftable_ref_record ref = { NULL };
-	int err = 0;
-
-	if (mod->add_len > 0) {
-		struct find_arg arg = {
-			.names = mod->add,
-			.want = prefix,
-		};
-		int idx = binsearch(mod->add_len, find_name, &arg);
-		if (idx < mod->add_len &&
-		    !strncmp(prefix, mod->add[idx], strlen(prefix)))
-			goto done;
-	}
-	err = reftable_table_seek_ref(&mod->tab, &it, prefix);
-	if (err)
-		goto done;
-
-	while (1) {
-		err = reftable_iterator_next_ref(&it, &ref);
-		if (err)
-			goto done;
-
-		if (mod->del_len > 0) {
-			struct find_arg arg = {
-				.names = mod->del,
-				.want = ref.refname,
-			};
-			int idx = binsearch(mod->del_len, find_name, &arg);
-			if (idx < mod->del_len &&
-			    !strcmp(ref.refname, mod->del[idx])) {
-				continue;
-			}
-		}
-
-		if (strncmp(ref.refname, prefix, strlen(prefix))) {
-			err = 1;
-			goto done;
-		}
-		err = 0;
-		goto done;
-	}
-
-done:
-	reftable_ref_record_release(&ref);
-	reftable_iterator_destroy(&it);
-	return err;
-}
-
-static int validate_refname(const char *name)
-{
-	while (1) {
-		char *next = strchr(name, '/');
-		if (!*name) {
-			return REFTABLE_REFNAME_ERROR;
-		}
-		if (!next) {
-			return 0;
-		}
-		if (next - name == 0 || (next - name == 1 && *name == '.') ||
-		    (next - name == 2 && name[0] == '.' && name[1] == '.'))
-			return REFTABLE_REFNAME_ERROR;
-		name = next + 1;
-	}
-	return 0;
-}
-
-int validate_ref_record_addition(struct reftable_table tab,
-				 struct reftable_ref_record *recs, size_t sz)
-{
-	struct modification mod = {
-		.tab = tab,
-		.add = reftable_calloc(sz, sizeof(*mod.add)),
-		.del = reftable_calloc(sz, sizeof(*mod.del)),
-	};
-	int i = 0;
-	int err = 0;
-	for (; i < sz; i++) {
-		if (reftable_ref_record_is_deletion(&recs[i])) {
-			mod.del[mod.del_len++] = recs[i].refname;
-		} else {
-			mod.add[mod.add_len++] = recs[i].refname;
-		}
-	}
-
-	err = modification_validate(&mod);
-	modification_release(&mod);
-	return err;
-}
-
-static void strbuf_trim_component(struct strbuf *sl)
-{
-	while (sl->len > 0) {
-		int is_slash = (sl->buf[sl->len - 1] == '/');
-		strbuf_setlen(sl, sl->len - 1);
-		if (is_slash)
-			break;
-	}
-}
-
-int modification_validate(struct modification *mod)
-{
-	struct strbuf slashed = STRBUF_INIT;
-	int err = 0;
-	int i = 0;
-	for (; i < mod->add_len; i++) {
-		err = validate_refname(mod->add[i]);
-		if (err)
-			goto done;
-		strbuf_reset(&slashed);
-		strbuf_addstr(&slashed, mod->add[i]);
-		strbuf_addstr(&slashed, "/");
-
-		err = modification_has_ref_with_prefix(mod, slashed.buf);
-		if (err == 0) {
-			err = REFTABLE_NAME_CONFLICT;
-			goto done;
-		}
-		if (err < 0)
-			goto done;
-
-		strbuf_reset(&slashed);
-		strbuf_addstr(&slashed, mod->add[i]);
-		while (slashed.len) {
-			strbuf_trim_component(&slashed);
-			err = modification_has_ref(mod, slashed.buf);
-			if (err == 0) {
-				err = REFTABLE_NAME_CONFLICT;
-				goto done;
-			}
-			if (err < 0)
-				goto done;
-		}
-	}
-	err = 0;
-done:
-	strbuf_release(&slashed);
-	return err;
-}
diff --git a/reftable/refname.h b/reftable/refname.h
deleted file mode 100644
index a24b40fcb4..0000000000
--- a/reftable/refname.h
+++ /dev/null
@@ -1,29 +0,0 @@
-/*
-  Copyright 2020 Google LLC
-
-  Use of this source code is governed by a BSD-style
-  license that can be found in the LICENSE file or at
-  https://developers.google.com/open-source/licenses/bsd
-*/
-#ifndef REFNAME_H
-#define REFNAME_H
-
-#include "reftable-record.h"
-#include "reftable-generic.h"
-
-struct modification {
-	struct reftable_table tab;
-
-	char **add;
-	size_t add_len;
-
-	char **del;
-	size_t del_len;
-};
-
-int validate_ref_record_addition(struct reftable_table tab,
-				 struct reftable_ref_record *recs, size_t sz);
-
-int modification_validate(struct modification *mod);
-
-#endif
diff --git a/reftable/refname_test.c b/reftable/refname_test.c
deleted file mode 100644
index b9cc62554e..0000000000
--- a/reftable/refname_test.c
+++ /dev/null
@@ -1,101 +0,0 @@
-/*
-Copyright 2020 Google LLC
-
-Use of this source code is governed by a BSD-style
-license that can be found in the LICENSE file or at
-https://developers.google.com/open-source/licenses/bsd
-*/
-
-#include "basics.h"
-#include "block.h"
-#include "blocksource.h"
-#include "reader.h"
-#include "record.h"
-#include "refname.h"
-#include "reftable-error.h"
-#include "reftable-writer.h"
-#include "system.h"
-
-#include "test_framework.h"
-#include "reftable-tests.h"
-
-struct testcase {
-	char *add;
-	char *del;
-	int error_code;
-};
-
-static void test_conflict(void)
-{
-	struct reftable_write_options opts = { 0 };
-	struct strbuf buf = STRBUF_INIT;
-	struct reftable_writer *w =
-		reftable_new_writer(&strbuf_add_void, &noop_flush, &buf, &opts);
-	struct reftable_ref_record rec = {
-		.refname = "a/b",
-		.value_type = REFTABLE_REF_SYMREF,
-		.value.symref = "destination", /* make sure it's not a symref.
-						*/
-		.update_index = 1,
-	};
-	int err;
-	int i;
-	struct reftable_block_source source = { NULL };
-	struct reftable_reader *rd = NULL;
-	struct reftable_table tab = { NULL };
-	struct testcase cases[] = {
-		{ "a/b/c", NULL, REFTABLE_NAME_CONFLICT },
-		{ "b", NULL, 0 },
-		{ "a", NULL, REFTABLE_NAME_CONFLICT },
-		{ "a", "a/b", 0 },
-
-		{ "p/", NULL, REFTABLE_REFNAME_ERROR },
-		{ "p//q", NULL, REFTABLE_REFNAME_ERROR },
-		{ "p/./q", NULL, REFTABLE_REFNAME_ERROR },
-		{ "p/../q", NULL, REFTABLE_REFNAME_ERROR },
-
-		{ "a/b/c", "a/b", 0 },
-		{ NULL, "a//b", 0 },
-	};
-	reftable_writer_set_limits(w, 1, 1);
-
-	err = reftable_writer_add_ref(w, &rec);
-	EXPECT_ERR(err);
-
-	err = reftable_writer_close(w);
-	EXPECT_ERR(err);
-	reftable_writer_free(w);
-
-	block_source_from_strbuf(&source, &buf);
-	err = reftable_new_reader(&rd, &source, "filename");
-	EXPECT_ERR(err);
-
-	reftable_table_from_reader(&tab, rd);
-
-	for (i = 0; i < ARRAY_SIZE(cases); i++) {
-		struct modification mod = {
-			.tab = tab,
-		};
-
-		if (cases[i].add) {
-			mod.add = &cases[i].add;
-			mod.add_len = 1;
-		}
-		if (cases[i].del) {
-			mod.del = &cases[i].del;
-			mod.del_len = 1;
-		}
-
-		err = modification_validate(&mod);
-		EXPECT(err == cases[i].error_code);
-	}
-
-	reftable_reader_free(rd);
-	strbuf_release(&buf);
-}
-
-int refname_test_main(int argc, const char *argv[])
-{
-	RUN_TEST(test_conflict);
-	return 0;
-}
diff --git a/reftable/reftable-error.h b/reftable/reftable-error.h
index 4c457aaaf8..3a5f5b92c6 100644
--- a/reftable/reftable-error.h
+++ b/reftable/reftable-error.h
@@ -48,9 +48,6 @@ enum reftable_error {
 	/* Wrote a table without blocks. */
 	REFTABLE_EMPTY_TABLE_ERROR = -8,
 
-	/* Dir/file conflict. */
-	REFTABLE_NAME_CONFLICT = -9,
-
 	/* Invalid ref name. */
 	REFTABLE_REFNAME_ERROR = -10,
 
diff --git a/reftable/reftable-tests.h b/reftable/reftable-tests.h
index 0019cbcfa4..114cc3d053 100644
--- a/reftable/reftable-tests.h
+++ b/reftable/reftable-tests.h
@@ -14,7 +14,6 @@ int block_test_main(int argc, const char **argv);
 int merged_test_main(int argc, const char **argv);
 int pq_test_main(int argc, const char **argv);
 int record_test_main(int argc, const char **argv);
-int refname_test_main(int argc, const char **argv);
 int readwrite_test_main(int argc, const char **argv);
 int stack_test_main(int argc, const char **argv);
 int tree_test_main(int argc, const char **argv);
diff --git a/reftable/reftable-writer.h b/reftable/reftable-writer.h
index 7c7cae5f99..3c119e2bbb 100644
--- a/reftable/reftable-writer.h
+++ b/reftable/reftable-writer.h
@@ -38,10 +38,6 @@ struct reftable_write_options {
 	/* Default mode for creating files. If unset, use 0666 (+umask) */
 	unsigned int default_permissions;
 
-	/* boolean: do not check ref names for validity or dir/file conflicts.
-	 */
-	unsigned skip_name_check : 1;
-
 	/* boolean: copy log messages exactly. If unset, check that the message
 	 *   is a single line, and add '\n' if missing.
 	 */
diff --git a/reftable/stack.c b/reftable/stack.c
index 1ecf1b9751..e264df5ced 100644
--- a/reftable/stack.c
+++ b/reftable/stack.c
@@ -12,8 +12,8 @@ https://developers.google.com/open-source/licenses/bsd
 #include "system.h"
 #include "merged.h"
 #include "reader.h"
-#include "refname.h"
 #include "reftable-error.h"
+#include "reftable-generic.h"
 #include "reftable-record.h"
 #include "reftable-merged.h"
 #include "writer.h"
@@ -27,8 +27,6 @@ static int stack_write_compact(struct reftable_stack *st,
 			       struct reftable_writer *wr,
 			       size_t first, size_t last,
 			       struct reftable_log_expiry_config *config);
-static int stack_check_addition(struct reftable_stack *st,
-				const char *new_tab_name);
 static void reftable_addition_close(struct reftable_addition *add);
 static int reftable_stack_reload_maybe_reuse(struct reftable_stack *st,
 					     int reuse_open);
@@ -781,10 +779,6 @@ int reftable_addition_add(struct reftable_addition *add,
 		goto done;
 	}
 
-	err = stack_check_addition(add->stack, get_tempfile_path(tab_file));
-	if (err < 0)
-		goto done;
-
 	if (wr->min_update_index < add->next_update_index) {
 		err = REFTABLE_API_ERROR;
 		goto done;
@@ -1340,65 +1334,6 @@ done:
 	return err;
 }
 
-static int stack_check_addition(struct reftable_stack *st,
-				const char *new_tab_name)
-{
-	int err = 0;
-	struct reftable_block_source src = { NULL };
-	struct reftable_reader *rd = NULL;
-	struct reftable_table tab = { NULL };
-	struct reftable_ref_record *refs = NULL;
-	struct reftable_iterator it = { NULL };
-	int cap = 0;
-	int len = 0;
-	int i = 0;
-
-	if (st->config.skip_name_check)
-		return 0;
-
-	err = reftable_block_source_from_file(&src, new_tab_name);
-	if (err < 0)
-		goto done;
-
-	err = reftable_new_reader(&rd, &src, new_tab_name);
-	if (err < 0)
-		goto done;
-
-	err = reftable_reader_seek_ref(rd, &it, "");
-	if (err > 0) {
-		err = 0;
-		goto done;
-	}
-	if (err < 0)
-		goto done;
-
-	while (1) {
-		struct reftable_ref_record ref = { NULL };
-		err = reftable_iterator_next_ref(&it, &ref);
-		if (err > 0)
-			break;
-		if (err < 0)
-			goto done;
-
-		REFTABLE_ALLOC_GROW(refs, len + 1, cap);
-		refs[len++] = ref;
-	}
-
-	reftable_table_from_merged_table(&tab, reftable_stack_merged_table(st));
-
-	err = validate_ref_record_addition(tab, refs, len);
-
-done:
-	for (i = 0; i < len; i++) {
-		reftable_ref_record_release(&refs[i]);
-	}
-
-	free(refs);
-	reftable_iterator_destroy(&it);
-	reftable_reader_free(rd);
-	return err;
-}
-
 static int is_table_name(const char *s)
 {
 	const char *dot = strrchr(s, '.');
diff --git a/reftable/stack_test.c b/reftable/stack_test.c
index 0dc9a44648..b88097c3b6 100644
--- a/reftable/stack_test.c
+++ b/reftable/stack_test.c
@@ -353,44 +353,6 @@ static void test_reftable_stack_transaction_api_performs_auto_compaction(void)
 	clear_dir(dir);
 }
 
-static void test_reftable_stack_validate_refname(void)
-{
-	struct reftable_write_options cfg = { 0 };
-	struct reftable_stack *st = NULL;
-	int err;
-	char *dir = get_tmp_dir(__LINE__);
-
-	int i;
-	struct reftable_ref_record ref = {
-		.refname = "a/b",
-		.update_index = 1,
-		.value_type = REFTABLE_REF_SYMREF,
-		.value.symref = "master",
-	};
-	char *additions[] = { "a", "a/b/c" };
-
-	err = reftable_new_stack(&st, dir, cfg);
-	EXPECT_ERR(err);
-
-	err = reftable_stack_add(st, &write_test_ref, &ref);
-	EXPECT_ERR(err);
-
-	for (i = 0; i < ARRAY_SIZE(additions); i++) {
-		struct reftable_ref_record ref = {
-			.refname = additions[i],
-			.update_index = 1,
-			.value_type = REFTABLE_REF_SYMREF,
-			.value.symref = "master",
-		};
-
-		err = reftable_stack_add(st, &write_test_ref, &ref);
-		EXPECT(err == REFTABLE_NAME_CONFLICT);
-	}
-
-	reftable_stack_destroy(st);
-	clear_dir(dir);
-}
-
 static int write_error(struct reftable_writer *wr, void *arg)
 {
 	return *((int *)arg);
@@ -1097,7 +1059,6 @@ int stack_test_main(int argc, const char *argv[])
 	RUN_TEST(test_reftable_stack_transaction_api_performs_auto_compaction);
 	RUN_TEST(test_reftable_stack_update_index_check);
 	RUN_TEST(test_reftable_stack_uptodate);
-	RUN_TEST(test_reftable_stack_validate_refname);
 	RUN_TEST(test_sizes_to_segments);
 	RUN_TEST(test_sizes_to_segments_all_equal);
 	RUN_TEST(test_sizes_to_segments_empty);
diff --git a/t/helper/test-reftable.c b/t/helper/test-reftable.c
index 00237ef0d9..bae731669c 100644
--- a/t/helper/test-reftable.c
+++ b/t/helper/test-reftable.c
@@ -13,7 +13,6 @@ int cmd__reftable(int argc, const char **argv)
 	readwrite_test_main(argc, argv);
 	merged_test_main(argc, argv);
 	stack_test_main(argc, argv);
-	refname_test_main(argc, argv);
 	return 0;
 }