diff --git a/Documentation/config/rerere.adoc b/Documentation/config/rerere.adoc index 3a78b5ebb1dc02..80c38ee951dd0f 100644 --- a/Documentation/config/rerere.adoc +++ b/Documentation/config/rerere.adoc @@ -10,3 +10,13 @@ rerere.enabled:: enabled if there is an `rr-cache` directory under the `$GIT_DIR`, e.g. if "rerere" was previously used in the repository. + +rerere.lockTimeout:: + The length of time, in milliseconds, to wait for the rerere + lock when another process holds it, typically a background + `git rerere gc`. Value 0 means not to wait at all; -1 means + to wait indefinitely. Default is 1000 (i.e., wait for 1 + second). When the time is up, the command fails as it does + for any other lock it cannot take. A `git rerere gc` run by + `git maintenance run --auto` or `git gc --auto` does not wait + and does nothing while the lock is held. diff --git a/builtin/gc.c b/builtin/gc.c index 57a3520263d7be..7ad3987b717ff5 100644 --- a/builtin/gc.c +++ b/builtin/gc.c @@ -385,12 +385,14 @@ static int worktree_prune_condition(struct gc_config *cfg) return should_prune; } -static int maintenance_task_rerere_gc(struct maintenance_run_opts *opts UNUSED, +static int maintenance_task_rerere_gc(struct maintenance_run_opts *opts, struct gc_config *cfg UNUSED) { struct child_process rerere_cmd = CHILD_PROCESS_INIT; rerere_cmd.git_cmd = 1; strvec_pushl(&rerere_cmd.args, "rerere", "gc", NULL); + if (opts->auto_flag) + strvec_push(&rerere_cmd.args, "--skip-locked"); return run_command(&rerere_cmd); } diff --git a/builtin/rerere.c b/builtin/rerere.c index a056cb791b4c80..91cb3c86682c15 100644 --- a/builtin/rerere.c +++ b/builtin/rerere.c @@ -56,16 +56,21 @@ int cmd_rerere(int argc, struct repository *repo UNUSED) { struct string_list merge_rr = STRING_LIST_INIT_DUP; - int autoupdate = -1, flags = 0; + int autoupdate = -1, skip_locked = 0, flags = 0; struct option options[] = { OPT_SET_INT(0, "rerere-autoupdate", &autoupdate, N_("register clean resolutions in index"), 1), + OPT_HIDDEN_BOOL(0, "skip-locked", &skip_locked, + N_("skip gc while another process holds the lock")), OPT_END(), }; argc = parse_options(argc, argv, prefix, options, rerere_usage, 0); + if (skip_locked && (argc < 1 || strcmp(argv[0], "gc"))) + die(_("the option '%s' requires '%s'"), "--skip-locked", "gc"); + repo_config(the_repository, git_xmerge_config, NULL); if (autoupdate == 1) @@ -94,7 +99,8 @@ int cmd_rerere(int argc, if (!strcmp(argv[0], "clear")) { rerere_clear(the_repository, &merge_rr); } else if (!strcmp(argv[0], "gc")) - rerere_gc(the_repository, &merge_rr); + rerere_gc(the_repository, &merge_rr, + skip_locked ? RERERE_GC_NOWAIT : 0); else if (!strcmp(argv[0], "status")) { if (setup_rerere(the_repository, &merge_rr, flags | RERERE_READONLY) < 0) diff --git a/rerere.c b/rerere.c index 1c3745d9e3279a..889ec700dd9e8e 100644 --- a/rerere.c +++ b/rerere.c @@ -33,6 +33,9 @@ static int rerere_enabled = -1; /* automatically update cleanly resolved paths to the index */ static int rerere_autoupdate; +/* how long to wait for MERGE_RR.lock, in milliseconds */ +static int rerere_lock_timeout_ms = 1000; + #define RR_HAS_POSTIMAGE 1 #define RR_HAS_PREIMAGE 2 struct rerere_dir { @@ -850,6 +853,8 @@ static void git_rerere_config(void) { repo_config_get_bool(the_repository, "rerere.enabled", &rerere_enabled); repo_config_get_bool(the_repository, "rerere.autoupdate", &rerere_autoupdate); + repo_config_get_int(the_repository, "rerere.locktimeout", + &rerere_lock_timeout_ms); repo_config(the_repository, git_default_config, NULL); } @@ -882,12 +887,29 @@ int setup_rerere(struct repository *r, struct string_list *merge_rr, int flags) if (flags & (RERERE_AUTOUPDATE|RERERE_NOAUTOUPDATE)) rerere_autoupdate = !!(flags & RERERE_AUTOUPDATE); - if (flags & RERERE_READONLY) + if ((flags & RERERE_READONLY) && (flags & RERERE_NOWAIT)) + BUG("RERERE_NOWAIT does not apply with RERERE_READONLY"); + if (flags & RERERE_READONLY) { fd = 0; - else - fd = repo_hold_lock_file_for_update(r, &write_lock, - git_path_merge_rr(r), - LOCK_DIE_ON_ERROR); + } else { + int lock_flags = LOCK_DIE_ON_ERROR; + int timeout_ms = rerere_lock_timeout_ms; + + /* + * Another process may hold the lock for a while, e.g. + * "git rerere gc" while it prunes rr-cache, so wait for + * it instead of dying right away. + */ + if (flags & RERERE_NOWAIT) { + lock_flags = 0; + timeout_ms = 0; + } + fd = repo_hold_lock_file_for_update_timeout(r, &write_lock, + git_path_merge_rr(r), + lock_flags, timeout_ms); + if (fd < 0) + return -1; + } read_rr(r, merge_rr); return fd; } @@ -1272,7 +1294,8 @@ bool rerere_gc_needed(struct repository *r, size_t limit) return needed; } -void rerere_gc(struct repository *r, struct string_list *rr) +void rerere_gc(struct repository *r, struct string_list *rr, + enum rerere_gc_flags flags) { struct string_list to_remove = STRING_LIST_INIT_DUP; DIR *dir; @@ -1282,7 +1305,8 @@ void rerere_gc(struct repository *r, struct string_list *rr) timestamp_t cutoff_resolve; struct strbuf buf = STRBUF_INIT; - if (setup_rerere(r, rr, 0) < 0) + if (setup_rerere(r, rr, + (flags & RERERE_GC_NOWAIT) ? RERERE_NOWAIT : 0) < 0) return; rerere_gc_cutoffs(r, &cutoff_resolve, &cutoff_noresolve); diff --git a/rerere.h b/rerere.h index feeb0e2c9fe61b..61e986475b82d6 100644 --- a/rerere.h +++ b/rerere.h @@ -10,6 +10,8 @@ struct repository; #define RERERE_AUTOUPDATE 01 #define RERERE_NOAUTOUPDATE 02 #define RERERE_READONLY 04 +/* If MERGE_RR.lock is taken, return -1 as if rerere were disabled */ +#define RERERE_NOWAIT 010 /* * Marks paths that have been hand-resolved and added to the @@ -37,7 +39,14 @@ const char *rerere_path(struct strbuf *buf, const struct rerere_id *, int rerere_forget(struct repository *, struct pathspec *); int rerere_remaining(struct repository *, struct string_list *); void rerere_clear(struct repository *, struct string_list *); -void rerere_gc(struct repository *, struct string_list *); + +enum rerere_gc_flags { + /* Skip the operation in case the MERGE_RR.lock is already taken. */ + RERERE_GC_NOWAIT = (1 << 0), +}; + +void rerere_gc(struct repository *, struct string_list *, + enum rerere_gc_flags flags); /* * Check whether garbage collection for rerere entries is needed, which is diff --git a/t/t4200-rerere.sh b/t/t4200-rerere.sh index 7bb601e117ec35..527a872c00844d 100755 --- a/t/t4200-rerere.sh +++ b/t/t4200-rerere.sh @@ -242,6 +242,85 @@ test_expect_success 'old records rest in peace' ' test_path_is_missing $rr2/preimage ' +test_expect_success 'gc --skip-locked does nothing while MERGE_RR is locked' ' + mkdir -p $rr2 && + echo Hello >$rr2/preimage && + test-tool chmtime =$just_over_15_days_ago $rr2/preimage && + + test_when_finished "rm -f .git/MERGE_RR.lock" && + >.git/MERGE_RR.lock && + git rerere gc --skip-locked 2>err && + test_must_be_empty err && + test_path_is_file $rr2/preimage +' + +test_expect_success 'gc --skip-locked prunes while MERGE_RR is not locked' ' + mkdir -p $rr2 && + echo Hello >$rr2/preimage && + test-tool chmtime =$just_over_15_days_ago $rr2/preimage && + + git rerere gc --skip-locked && + test_path_is_missing $rr2/preimage +' + +test_expect_success '--skip-locked is only accepted by gc' ' + test_must_fail git rerere --skip-locked clear 2>err && + test_grep "option .--skip-locked. requires .gc." err +' + +test_expect_success 'a held lock is waited out within rerere.lockTimeout' ' + git reset --hard && + rm -rf $rr && + test_when_finished "rm -f .git/MERGE_RR.lock" && + >.git/MERGE_RR.lock && + { + ( sleep 1 && rm -f .git/MERGE_RR.lock ) & + } && + test_must_fail git -c rerere.lockTimeout=5000 merge first 2>err && + wait && + test_grep ! "MERGE_RR" err && + test_grep "^=======\$" $rr/preimage +' + +test_expect_success 'merge fails once rerere.lockTimeout is up' ' + git reset --hard && + rm -rf $rr && + test_when_finished "rm -f .git/MERGE_RR.lock" && + >.git/MERGE_RR.lock && + test_must_fail git -c rerere.lockTimeout=0 merge first 2>err && + test_grep "Unable to create" err && + test_grep "^=======\$" a1 && + test_path_is_missing $rr/preimage +' + +test_expect_success 'rerere, forget, clear and gc fail on a lock they cannot take' ' + test_when_finished "rm -f .git/MERGE_RR.lock" && + >.git/MERGE_RR.lock && + test_must_fail git -c rerere.lockTimeout=0 rerere 2>err && + test_grep "Unable to create" err && + test_must_fail git -c rerere.lockTimeout=0 rerere forget a1 2>err && + test_grep "Unable to create" err && + test_must_fail git -c rerere.lockTimeout=0 rerere clear 2>err && + test_grep "Unable to create" err && + test_must_fail git -c rerere.lockTimeout=0 rerere gc 2>err && + test_grep "Unable to create" err +' + +test_expect_success 'rebase --abort fails on a lock it cannot take' ' + git reset --hard && + git checkout -b lock-held-abort third && + test_when_finished "git checkout third && git branch -D lock-held-abort" && + test_must_fail git rebase first && + test_when_finished "rm -f .git/MERGE_RR.lock" && + >.git/MERGE_RR.lock && + test_must_fail git -c rerere.lockTimeout=0 rebase --abort 2>err && + test_grep "Unable to create" err && + test_path_is_dir .git/rebase-merge && + rm .git/MERGE_RR.lock && + git rebase --abort && + test_path_is_missing .git/rebase-merge +' + rerere_gc_custom_expiry_test () { five_days="$1" right_now="$2" test_expect_success "rerere gc with custom expiry ($five_days, $right_now)" ' diff --git a/t/t7900-maintenance.sh b/t/t7900-maintenance.sh index 4f65fa9439c0b8..f0f9b37d4ff7d5 100755 --- a/t/t7900-maintenance.sh +++ b/t/t7900-maintenance.sh @@ -1007,9 +1007,17 @@ test_expect_rerere_gc () { shift fi + # An automatic run passes --skip-locked to "git rerere gc". + skip_locked= + case " $* " in + *" --auto "*) + skip_locked=--skip-locked + ;; + esac + rm -f "rerere-gc.txt" && GIT_TRACE2_EVENT="$(pwd)/rerere-gc.txt" "$@" && - test_subcommand $negate git rerere gc .git/MERGE_RR.lock && + test_expect_rerere_gc git -c maintenance.rerere-gc.auto=-1 maintenance run --auto --task=rerere-gc +' + +test_expect_success 'rerere-gc task without --auto fails while MERGE_RR is locked' ' + test_when_finished "rm -rf .git/rr-cache .git/MERGE_RR.lock" && + mkdir .git/rr-cache && + >.git/MERGE_RR.lock && + test_must_fail git -c rerere.lockTimeout=0 maintenance run --task=rerere-gc 2>err && + test_grep "Unable to create" err +' + test_expect_success '--auto and --schedule incompatible' ' test_must_fail git maintenance run --auto --schedule=daily 2>err && test_grep "cannot be used together" err