From fa655d8411cc2d7ffcf898e53a1493c737d7de68 Mon Sep 17 00:00:00 2001 From: Ben Peart Date: Thu, 16 Aug 2018 18:27:11 +0000 Subject: checkout: optimize "git checkout -b " Skip merging the commit, updating the index and working directory if and only if we are creating a new branch via "git checkout -b ." Any other checkout options will still go through the former code path. If sparse_checkout is on, require the user to manually opt in to this optimzed behavior by setting the config setting checkout.optimizeNewBranch to true as we will no longer update the skip-worktree bit in the index, nor add/remove files in the working directory to reflect the current sparse checkout settings. For comparison, running "git checkout -b " on a large repo takes: 14.6 seconds - without this patch 0.3 seconds - with this patch Signed-off-by: Ben Peart Signed-off-by: Junio C Hamano --- Documentation/config.txt | 8 +++ builtin/checkout.c | 120 +++++++++++++++++++++++++++++++++++++-- t/t1090-sparse-checkout-scope.sh | 14 +++++ 3 files changed, 138 insertions(+), 4 deletions(-) diff --git a/Documentation/config.txt b/Documentation/config.txt index 43b2de7b5f..1a2deeaf20 100644 --- a/Documentation/config.txt +++ b/Documentation/config.txt @@ -1101,6 +1101,14 @@ browser..path:: browse HTML help (see `-w` option in linkgit:git-help[1]) or a working repository in gitweb (see linkgit:git-instaweb[1]). +checkout.optimizeNewBranch + Optimizes the performance of "git checkout -b " when + using sparse-checkout. When set to true, git will not update the + repo based on the current sparse-checkout settings. This means it + will not update the skip-worktree bit in the index nor add/remove + files in the working directory to reflect the current sparse checkout + settings nor will it show the local changes. + clean.requireForce:: A boolean to make git-clean do nothing unless given -f, -i or -n. Defaults to true. diff --git a/builtin/checkout.c b/builtin/checkout.c index 28627650cd..21bac3a561 100644 --- a/builtin/checkout.c +++ b/builtin/checkout.c @@ -24,6 +24,8 @@ #include "submodule-config.h" #include "submodule.h" +static int checkout_optimize_new_branch; + static const char * const checkout_usage[] = { N_("git checkout [] "), N_("git checkout [] [] -- ..."), @@ -41,6 +43,10 @@ struct checkout_opts { int ignore_skipworktree; int ignore_other_worktrees; int show_progress; + /* + * If new checkout options are added, skip_merge_working_tree + * should be updated accordingly. + */ const char *new_branch; const char *new_branch_force; @@ -471,6 +477,98 @@ static void setup_branch_path(struct branch_info *branch) branch->path = strbuf_detach(&buf, NULL); } +/* + * Skip merging the trees, updating the index and working directory if and + * only if we are creating a new branch via "git checkout -b ." + */ +static int skip_merge_working_tree(const struct checkout_opts *opts, + const struct branch_info *old_branch_info, + const struct branch_info *new_branch_info) +{ + /* + * Do the merge if sparse checkout is on and the user has not opted in + * to the optimized behavior + */ + if (core_apply_sparse_checkout && !checkout_optimize_new_branch) + return 0; + + /* + * We must do the merge if we are actually moving to a new commit. + */ + if (!old_branch_info->commit || !new_branch_info->commit || + oidcmp(&old_branch_info->commit->object.oid, &new_branch_info->commit->object.oid)) + return 0; + + /* + * opts->patch_mode cannot be used with switching branches so is + * not tested here + */ + + /* + * opts->quiet only impacts output so doesn't require a merge + */ + + /* + * Honor the explicit request for a three-way merge or to throw away + * local changes + */ + if (opts->merge || opts->force) + return 0; + + /* + * --detach is documented as "updating the index and the files in the + * working tree" but this optimization skips those steps so fall through + * to the regular code path. + */ + if (opts->force_detach) + return 0; + + /* + * opts->writeout_stage cannot be used with switching branches so is + * not tested here + */ + + /* + * Honor the explicit ignore requests + */ + if (!opts->overwrite_ignore || opts->ignore_skipworktree || + opts->ignore_other_worktrees) + return 0; + + /* + * opts->show_progress only impacts output so doesn't require a merge + */ + + /* + * If we aren't creating a new branch any changes or updates will + * happen in the existing branch. Since that could only be updating + * the index and working directory, we don't want to skip those steps + * or we've defeated any purpose in running the command. + */ + if (!opts->new_branch) + return 0; + + /* + * new_branch_force is defined to "create/reset and checkout a branch" + * so needs to go through the merge to do the reset + */ + if (opts->new_branch_force) + return 0; + + /* + * A new orphaned branch requrires the index and the working tree to be + * adjusted to + */ + if (opts->new_orphan_branch) + return 0; + + /* + * Remaining variables are not checkout options but used to track state + */ + + return 1; +} + static int merge_working_tree(const struct checkout_opts *opts, struct branch_info *old_branch_info, struct branch_info *new_branch_info, @@ -845,10 +943,19 @@ static int switch_branches(const struct checkout_opts *opts, parse_commit_or_die(new_branch_info->commit); } - ret = merge_working_tree(opts, &old_branch_info, new_branch_info, &writeout_error); - if (ret) { - free(path_to_free); - return ret; + /* optimize the "checkout -b path */ + if (skip_merge_working_tree(opts, &old_branch_info, new_branch_info)) { + if (!checkout_optimize_new_branch && !opts->quiet) { + if (read_cache_preload(NULL) < 0) + return error(_("index file corrupt")); + show_local_changes(&new_branch_info->commit->object, &opts->diff_options); + } + } else { + ret = merge_working_tree(opts, &old_branch_info, new_branch_info, &writeout_error); + if (ret) { + free(path_to_free); + return ret; + } } if (!opts->quiet && !old_branch_info.path && old_branch_info.commit && new_branch_info->commit != old_branch_info.commit) @@ -863,6 +970,11 @@ static int switch_branches(const struct checkout_opts *opts, static int git_checkout_config(const char *var, const char *value, void *cb) { + if (!strcmp(var, "checkout.optimizenewbranch")) { + checkout_optimize_new_branch = git_config_bool(var, value); + return 0; + } + if (!strcmp(var, "diff.ignoresubmodules")) { struct checkout_opts *opts = cb; handle_ignore_submodules_arg(&opts->diff_options, value); diff --git a/t/t1090-sparse-checkout-scope.sh b/t/t1090-sparse-checkout-scope.sh index 1f61eb3e88..25d7c700f6 100755 --- a/t/t1090-sparse-checkout-scope.sh +++ b/t/t1090-sparse-checkout-scope.sh @@ -31,6 +31,20 @@ test_expect_success 'perform sparse checkout of master' ' test_path_is_file c ' +test_expect_success 'checkout -b checkout.optimizeNewBranch interaction' ' + cp .git/info/sparse-checkout .git/info/sparse-checkout.bak && + test_when_finished " + mv -f .git/info/sparse-checkout.bak .git/info/sparse-checkout + git checkout master + " && + echo "/b" >>.git/info/sparse-checkout && + test "$(git ls-files -t b)" = "S b" && + git -c checkout.optimizeNewBranch=true checkout -b fast && + test "$(git ls-files -t b)" = "S b" && + git checkout -b slow && + test "$(git ls-files -t b)" = "H b" +' + test_expect_success 'merge feature branch into sparse checkout of master' ' git merge feature && test_path_is_file a && -- cgit v1.2.3