On Tue, Dec 19, 2017 at 2:44 PM, Jonathan Nieder <jrnieder@xxxxxxxxx> wrote: > Hi, > > I had trouble understanding what this fixes, so I'll try nitpicking a > bit as a sideways way to address that. > > Stefan Beller wrote: > >> With the previous patch applied (fix of the same() function), > > This tripped me up a bit. Usually commits assume that all previous > patches have already been applied, since that allows the maintainer to > apply the early part of a series on one day and the later part another > day without losing too much context. > > I think this intends to say something like > > Now that we allow recursing into an unchanged submodule (see > "unpack-trees: Fix same() for submodules", 2017-12-19), it is > possible for ... yup > >> the >> function `submodule_move_head` may be invoked with the same argument >> for the `old` and `new` state of a submodule, for example when you >> run `reset --hard --recurse-submodules` in the superproject that has no >> change in the gitlink entry, but only worktree related change in the >> submodule. The read-tree call in the submodule is not amused about >> the duplicate argument. > > What is the symptom of read-tree being unamused? Is that a sign that > these patches are out of order (i.e. that we should prepare to handle an > unchanged submodule first, and then adjust the caller to pass in > unchanged submodules)? > >> It turns out that we can omit the duplicate old argument in all forced >> cases anyway, so let's do that. > > What is the end-user visibile effect of such a change? E.g. what > becomes possible to a user that wasn't possible before? > > Among the commands you mentioned before: > > checkout -f > I think I would expect this not to touch a submodule that > hasn't changed, since that would be consistent with its > behavior on files that haven't changed. > > reset --hard > Nice! Yes, recursing into unchanged submodules is a big part > of the psychological comfort of being able to say "you can > always use reset --hard <commit> to get back to a known > state". I may have a different understanding of git commands than you do, but a plain "checkout -f" with no further arguments is the same as a hard reset IMHO, and could be used interchangeably? Rehashing the "What is a submodule?" discussion, I would claim that when its worktree is changed, we'd want checkout to restore the submodules worktree back, so I disagree with your assessment of checkout -f. > read-tree -u --reset > This is essentially the plumbing equivalent of reset --hard, > so it makes sense for them to be consistent. Ok. > > Based on the checkout -f case, if I've understood correctly then patch > 4/5 goes too far on it (but I could easily be convinced otherwise). Without 4/5 we cannot implement hard reset recursing into submodules as it is functionally the same as forced checkout except when we differentiate them on a higher layer? >> Signed-off-by: Stefan Beller <sbeller@xxxxxxxxxx> >> --- >> submodule.c | 4 +++- >> t/lib-submodule-update.sh | 2 +- >> 2 files changed, 4 insertions(+), 2 deletions(-) >> >> diff --git a/submodule.c b/submodule.c >> index fa25888783..db0f7ac51e 100644 >> --- a/submodule.c >> +++ b/submodule.c >> @@ -1653,7 +1653,9 @@ int submodule_move_head(const char *path, >> else >> argv_array_push(&cp.args, "-m"); >> >> - argv_array_push(&cp.args, old ? old : EMPTY_TREE_SHA1_HEX); >> + if (!(flags & SUBMODULE_MOVE_HEAD_FORCE)) >> + argv_array_push(&cp.args, old ? old : EMPTY_TREE_SHA1_HEX); > > Interesting. What is the effect when old != new? when the force flag is set we mostly pass in old="HEAD", which is technically correct, but not a sha1. (I assume you want to know what happens when two unequal sha1s are given; for that it will perform a 2 way merge instead of a complete reset) Thanks, Stefan
