On 10/5/2019 3:40 PM, Elijah Newren wrote:
> On Thu, Sep 19, 2019 at 3:06 PM Derrick Stolee via GitGitGadget
> <gitgitgadget@xxxxxxxxx> wrote:
>
>> During the 'git sparse-checkout init' call, we must first look
>> to see if HEAD is valid, or else we will fail while trying to
>> update the working directory. The first checkout will actually
>> update the working directory correctly.
>
> This is new since the RFC series, but I'm not sure I understand. Is
> the issue you're fixing here that a 'git init somerepo' would hit this
> codepath and print funny errors because HEAD doesn't exist yet and
> thus the whole `git read-tree -mu HEAD` stuff can't work? Or that
> when the remote has HEAD pointing at a bad commit that you get error
> messages different than expected?
At the point where `git clone --sparse` calls `git sparse-checkout init`,
there is no HEAD. We need to initialize the sparse-checkout before the
clone operation populates the working directory and creates the HEAD
ref. For that reason, `git read-tree -mu HEAD` wouldn't work. But that's
fine, since there is nothing to do. The index update will happen later.
>
>> diff --git a/builtin/sparse-checkout.c b/builtin/sparse-checkout.c
>> index 895479970d..656e6ebdd5 100644
>> --- a/builtin/sparse-checkout.c
>> +++ b/builtin/sparse-checkout.c
>> @@ -99,6 +99,7 @@ static int sparse_checkout_init(int argc, const char **argv)
>> char *sparse_filename;
>> FILE *fp;
>> int res;
>> + struct object_id oid;
>>
>> if (sc_enable_config())
>> return 1;
>> @@ -120,6 +121,11 @@ static int sparse_checkout_init(int argc, const char **argv)
>> fprintf(fp, "/*\n!/*/\n");
>> fclose(fp);
>>
>> + if (get_oid("HEAD", &oid)) {
>> + /* assume we are in a fresh repo */
>> + return 0;
>> + }
>> +
>> reset_dir:
>> return update_working_directory();
>> }
