branch: add --dry-run for --delete-merged

"git branch --dry-run --delete-merged ..." prints one line per ref that would be deleted without modifying refs or branch configuration. --dry-run is only meaningful together with --delete-merged and is rejected otherwise. Signed-off-by: Harald Nordgren <haraldnordgren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Harald Nordgren committed Jul 30, 2026 at 13:58 UTC 308d3bf9bb6080b403ee8c539ad503d80224014e
3 files changed +63 -6
Documentation/git-branch.adoc
+7 -1
@@ -25,7 +25,7 @@ git branch (-m|-M) [<old-branch>] <new-branch>
25 git branch (-c|-C) [<old-branch>] <new-branch>
26 git branch (-d|-D) [-r] <branch-name>...
27 git branch --edit-description [<branch-name>]
28 -git branch (--delete-merged <pattern>)... [<branch-pattern>...]
28 +git branch [--dry-run] (--delete-merged <pattern>)... [<branch-pattern>...]
29
30 DESCRIPTION
31 -----------
@@ -235,6 +235,12 @@ A branch whose work has not yet been merged into its upstream is
235 silently skipped. Delete it with `git branch -D` if you want to
236 remove it anyway.
237
238 +`--dry-run`::
239 + With `--delete-merged`, print which branches would be
240 + deleted and exit without touching any ref. Useful for
241 + sanity-checking a wide pattern like `'origin/*'` before
242 + committing to the deletion.
243 +
244 `-v`::
245 `-vv`::
246 `--verbose`::
builtin/branch.c
+19 -4
@@ -200,6 +200,7 @@ enum delete_branch_flags {
200 DELETE_BRANCH_QUIET = (1 << 1),
201 DELETE_BRANCH_SKIP_UNMERGED = (1 << 2),
202 DELETE_BRANCH_NO_HEAD_FALLBACK = (1 << 3),
203 + DELETE_BRANCH_DRY_RUN = (1 << 4),
204 };
205
206 static int check_branch_commit(const char *branchname, const char *refname,
@@ -342,13 +343,20 @@ static int delete_branches(int argc, const char **argv, int kinds,
343 free(target);
344 }
345
345 - if (refs_delete_refs(get_main_ref_store(the_repository), NULL, &refs_to_delete, REF_NO_DEREF))
346 + if (!(flags & DELETE_BRANCH_DRY_RUN) &&
347 + refs_delete_refs(get_main_ref_store(the_repository), NULL, &refs_to_delete, REF_NO_DEREF))
348 ret = 1;
349
350 for_each_string_list_item(item, &refs_to_delete) {
351 char *describe_ref = item->util;
352 char *name = item->string;
351 - if (!refs_ref_exists(get_main_ref_store(the_repository), name)) {
353 + if (flags & DELETE_BRANCH_DRY_RUN) {
354 + if (!(flags & DELETE_BRANCH_QUIET))
355 + printf(remote_branch
356 + ? _("Would delete remote-tracking branch %s (was %s).\n")
357 + : _("Would delete branch %s (was %s).\n"),
358 + name + branch_name_pos, describe_ref);
359 + } else if (!refs_ref_exists(get_main_ref_store(the_repository), name)) {
360 char *refname = name + branch_name_pos;
361 if (!(flags & DELETE_BRANCH_QUIET))
362 printf(remote_branch
@@ -882,7 +890,7 @@ static int delete_merged_branches(const struct strvec *upstreams,
890 DELETE_BRANCH_NO_HEAD_FALLBACK |
891 flags);
892
885 - if (!ret)
893 + if (!ret && !(flags & DELETE_BRANCH_DRY_RUN))
894 clear_deleted_upstreams(&protected_branch_names,
895 &deletable_branch_names);
896
@@ -960,6 +968,7 @@ int cmd_branch(int argc,
968 int delete = 0, rename = 0, copy = 0, list = 0,
969 unset_upstream = 0, show_current = 0, edit_description = 0;
970 struct strvec delete_merged = STRVEC_INIT;
971 + int dry_run = 0;
972 const char *new_upstream = NULL;
973 int noncreate_actions = 0;
974 /* possible options */
@@ -1016,6 +1025,8 @@ int cmd_branch(int argc,
1025 OPT_CALLBACK_F(0, "delete-merged", &delete_merged, N_("pattern"),
1026 N_("delete merged branches whose upstream matches <pattern> (repeatable)"),
1027 PARSE_OPT_NONEG, parse_opt_strvec),
1028 + OPT_BOOL(0, "dry-run", &dry_run,
1029 + N_("with --delete-merged, only print which branches would be deleted")),
1030 OPT__FORCE(&force, N_("force creation, move/rename, deletion"), PARSE_OPT_NOCOMPLETE),
1031 OPT_MERGED(&filter, N_("print only branches that are merged")),
1032 OPT_NO_MERGED(&filter, N_("print only branches that are not merged")),
@@ -1078,6 +1089,9 @@ int cmd_branch(int argc,
1089 if (noncreate_actions > 1)
1090 usage_with_options(builtin_branch_usage, options);
1091
1092 + if (dry_run && !delete_merged.nr)
1093 + die(_("--dry-run requires --delete-merged"));
1094 +
1095 if (recurse_submodules_explicit) {
1096 if (!submodule_propagate_branches)
1097 die(_("branch with --recurse-submodules can only be used if submodule.propagateBranches is enabled"));
@@ -1118,7 +1132,8 @@ int cmd_branch(int argc,
1132 goto out;
1133 } else if (delete_merged.nr) {
1134 ret = delete_merged_branches(&delete_merged, argv,
1121 - quiet ? DELETE_BRANCH_QUIET : 0);
1135 + (quiet ? DELETE_BRANCH_QUIET : 0) |
1136 + (dry_run ? DELETE_BRANCH_DRY_RUN : 0));
1137 goto out;
1138 } else if (show_current) {
1139 print_current_branch_name();
t/t3200-branch.sh
+37 -1
@@ -1938,6 +1938,19 @@ test_expect_success '--delete-merged deletes only selected merged branches' '
1938 git checkout -b tracks-other --track other/main &&
1939 sha=$(git rev-parse --short merged) &&
1940
1941 + git branch --dry-run --delete-merged origin/next merged >actual 2>&1 &&
1942 + echo "Would delete branch merged (was $sha)." >expect &&
1943 + test_cmp expect actual &&
1944 + git rev-parse --verify refs/heads/merged &&
1945 +
1946 + check_branches <<-\EOF &&
1947 + also-merged
1948 + main
1949 + merged
1950 + tracks-other
1951 + unmerged
1952 + EOF
1953 +
1954 git branch --delete-merged origin/next merged >actual 2>&1 &&
1955 echo "Deleted branch merged (was $sha)." >expect &&
1956 test_cmp expect actual &&
@@ -2003,9 +2016,12 @@ test_expect_success '--delete-merged keeps the upstream of a surviving branch' '
2016 git checkout -b topic --track feature &&
2017 git commit --allow-empty -m "topic work" &&
2018
2006 - git branch --delete-merged origin/next 2>err &&
2019 + git branch --dry-run --delete-merged origin/next >out &&
2020 + test_grep ! "feature" out &&
2021
2022 + git branch --delete-merged origin/next 2>err &&
2023 test_must_be_empty err &&
2024 +
2025 check_branches <<-\EOF &&
2026 feature
2027 main
@@ -2033,6 +2049,21 @@ test_expect_success '--delete-merged clears the deleted upstream of a protected
2049 git commit --allow-empty -m "tip work" &&
2050 sha=$(git rev-parse --short lower) &&
2051
2052 + git branch --dry-run --delete-merged origin/next --delete-merged lower >actual 2>&1 &&
2053 + echo "Would delete branch lower (was $sha)." >expect &&
2054 + test_cmp expect actual &&
2055 +
2056 + git config --local --get-regexp "branch\\.(lower|mid|tip)\\.(merge|remote)" >actual &&
2057 + cat >expect <<-\EOF &&
2058 + branch.lower.remote origin
2059 + branch.lower.merge refs/heads/next
2060 + branch.mid.remote .
2061 + branch.mid.merge refs/heads/lower
2062 + branch.tip.remote .
2063 + branch.tip.merge refs/heads/mid
2064 + EOF
2065 + test_cmp expect actual &&
2066 +
2067 git branch --delete-merged origin/next --delete-merged lower >actual 2>&1 &&
2068 echo "Deleted branch lower (was $sha)." >expect &&
2069 test_cmp expect actual &&
@@ -2120,4 +2151,9 @@ test_expect_success "branch -d still deletes a deleteMerged=false branch" '
2151 )
2152 '
2153
2154 +test_expect_success '--dry-run without --delete-merged is rejected' '
2155 + test_must_fail git -C forked branch --dry-run 2>err &&
2156 + test_grep "requires --delete-merged" err
2157 +'
2158 +
2159 test_done