It is very typical for Git newcomers to inadvertently create merges and worse; pushing them. This is one of the reasons many experienced users prefer to avoid 'git pull', and recommend newcomers to avoid it as well. To escape these problems--and keep 'git pull' useful--it has been suggested that 'git pull' barfs by default if the merge is non-fast-forward, which unfortunately would break backwards compatibility. This patch leaves everything in place to enable this new mode, but it only gets enabled if the user specifically configures it; pull.mode = ff-only. Later on this mode can be enabled by default. For the full discussion you can read: https://lore.kernel.org/git/5363BB9F.40102@xxxxxxxxxxx/ Signed-off-by: Felipe Contreras <felipe.contreras@xxxxxxxxx> --- Documentation/config/branch.txt | 4 +-- Documentation/config/pull.txt | 4 +-- builtin/pull.c | 5 +++- builtin/remote.c | 3 +++ rebase.c | 2 ++ rebase.h | 3 ++- t/t5520-pull.sh | 45 +++++++++++++++++++++++++++++++++ 7 files changed, 60 insertions(+), 6 deletions(-) diff --git a/Documentation/config/branch.txt b/Documentation/config/branch.txt index b57bf2c308..39f60cd8f7 100644 --- a/Documentation/config/branch.txt +++ b/Documentation/config/branch.txt @@ -98,8 +98,8 @@ for details). branch.<name>.pullmode:: When "git pull" is run, this determines if it would either merge or - rebase the fetched branch. The possible values are 'merge', and - 'rebase'. See "pull.mode" for doing this in a non + rebase the fetched branch. The possible values are 'merge', + 'rebase', and 'ff-only'. See "pull.mode" for doing this in a non branch-specific manner. branch.<name>.description:: diff --git a/Documentation/config/pull.txt b/Documentation/config/pull.txt index f4385cde33..40778d9120 100644 --- a/Documentation/config/pull.txt +++ b/Documentation/config/pull.txt @@ -32,8 +32,8 @@ for details). pull.mode:: When "git pull" is run, this determines if it would either merge or rebase the fetched branch. The possible values are 'merge', - and 'rebase'. See "branch.<name>.pullmode" for setting this on a - per-branch basis. + 'rebase', and 'ff-only'. See "branch.<name>.pullmode" for setting + this on a per-branch basis. pull.octopus:: The default merge strategy to use when pulling multiple branches diff --git a/builtin/pull.c b/builtin/pull.c index 7756c8aea1..5a67667b79 100644 --- a/builtin/pull.c +++ b/builtin/pull.c @@ -1088,6 +1088,9 @@ int cmd_pull(int argc, const char **argv, const char *prefix) can_ff = get_can_ff(&orig_head, &merge_heads.oid[0]); + if (mode == PULL_MODE_FF_ONLY && !can_ff) + die(_("The pull was not fast-forward, please either merge or rebase.\n")); + if (!opt_rebase && !can_ff && opt_verbosity >= 0 && (!opt_ff || !strcmp(opt_ff, "--ff"))) { advise(_("Pulling without specifying how to reconcile divergent branches is discouraged;\n" "you need to specify if you want a merge, or a rebase.\n" @@ -1095,7 +1098,7 @@ int cmd_pull(int argc, const char **argv, const char *prefix) "\n" " git config pull.mode merge # (the default strategy)\n" " git config pull.mode rebase\n" - " git config pull.ff only # fast-forward only\n" + " git config pull.mode ff-only # fast-forward only\n" "\n" "You can replace \"git config\" with \"git config --global\" to set a default\n" "preference for all repositories.\n" diff --git a/builtin/remote.c b/builtin/remote.c index 51b1e675e3..34d3ea9d38 100644 --- a/builtin/remote.c +++ b/builtin/remote.c @@ -335,6 +335,9 @@ static int config_read_branches(const char *key, const char *value, void *cb) case PULL_MODE_REBASE: info->rebase = REBASE_TRUE; break; + case PULL_MODE_FF_ONLY: + info->rebase = REBASE_TRUE; + break; default: info->rebase = REBASE_INVALID; break; diff --git a/rebase.c b/rebase.c index bdfca49886..c6233e888f 100644 --- a/rebase.c +++ b/rebase.c @@ -40,6 +40,8 @@ enum pull_mode_type pull_mode_parse_value(const char *value) return PULL_MODE_MERGE; else if (!strcmp(value, "rebase") || !strcmp(value, "r")) return PULL_MODE_REBASE; + else if (!strcmp(value, "ff-only") || !strcmp(value, "f")) + return PULL_MODE_FF_ONLY; return PULL_MODE_INVALID; } diff --git a/rebase.h b/rebase.h index 5ab8f4ddd5..432bcb55c4 100644 --- a/rebase.h +++ b/rebase.h @@ -17,7 +17,8 @@ enum pull_mode_type { PULL_MODE_INVALID = -1, PULL_MODE_DEFAULT = 0, PULL_MODE_MERGE, - PULL_MODE_REBASE + PULL_MODE_REBASE, + PULL_MODE_FF_ONLY }; enum pull_mode_type pull_mode_parse_value(const char *value); diff --git a/t/t5520-pull.sh b/t/t5520-pull.sh index eb0086bd1c..b5b007b175 100755 --- a/t/t5520-pull.sh +++ b/t/t5520-pull.sh @@ -861,4 +861,49 @@ test_expect_success 'git pull --rebase against local branch' ' test_cmp expect file2 ' +setup_other () { + test_when_finished "git checkout master && git branch -D other test" && + git checkout -b other $1 && + >new && + git add new && + git commit -m new && + git checkout -b test -t other && + git reset --hard master +} + +setup_ff () { + setup_other master +} + +setup_non_ff () { + setup_other master^ +} + +test_expect_success 'fast-forward (pull.mode=ff-only)' ' + setup_ff && + git -c pull.mode=ff-only pull +' + +test_expect_success 'non-fast-forward (pull.mode=ff-only)' ' + setup_non_ff && + test_must_fail git -c pull.mode=ff-only pull +' + +test_expect_success 'non-fast-forward with merge (pull.mode=ff-only)' ' + setup_non_ff && + git -c pull.mode=ff-only pull --merge +' + +test_expect_success 'non-fast-forward with rebase (pull.mode=ff-only)' ' + setup_non_ff && + git -c pull.mode=ff-only pull --rebase +' + +test_expect_success 'non-fast-forward error message (pull.mode=ff-only)' ' + setup_non_ff && + test_must_fail git -c pull.mode=ff-only pull 2> error && + cat error && + test_i18ngrep "The pull was not fast-forward" error +' + test_done -- 2.29.2
