On Mon, Nov 22 2021, Junio C Hamano wrote: > Teng Long <dyroneteng@xxxxxxxxx> writes: > >> Sometimes, we only want to get the objects from output of `ls-tree` >> and commands like `sed` or `cut` is usually used to intercept the >> origin output to achieve this purpose in practical. > > "in practical" -> "in practice". > > That's true and that is exactly this plumbing command was designed > to be used. > >> This commit supply an option names `--oid-only` to let `git ls-tree` >> only print out the OID of the object. `--oid-only` and `--name-only` >> are mutually exclusive in use. > > Teach the "--oid-only" option to tell the command to only show > the object name, just like "--name-only" option tells the > command to only show the path component, for each entry. These > two options are mutually exclusive. > > perhaps? > > The above leaves "mode-only" and "type-only". I wonder if it is a > better design to add just one new option, --hide-fields, and make > the existing --name-only into a synonym to > > git ls-tree --hide-fields=mode,type,object $T > > which would mean we do not need to end up with four mutually > exclusive commands, and anybody who wants to only see object names > can do > > git ls-tree --hide-fields=mode,type,file $T > > Note: the above uses the terminology in the OUTPUT FORMAT section; > if we want to use "name" instead of "file", I am perfectly OK with > it, but then we should update the documentation to match. > > Come to think of it, I think "--show-fields" may work even better > than "--hide-fields". We can use it to get rid of the "--long" > option: > > git ls-tree --show-fields=mode,type,object,size,file $T > > would be equivelent to > > git ls-tree --long $T > > The field order may need to be thought through, especially when "-z" > output is not being used. We may need a rule to require "file" to > be at the end, if exists, or even simpler rule "you can choose which > fields are shown but the order they come out is not affected" (i.e. > "--show-fields=mode,type" and "--show-fields=type,mode" give the > same output). > > I am OK if we started with "only a single field allowed" and extend > it to support multiple fields later (until that happens, we cannot > emulate the "--long" output, though). Then we do not have to answer > two tricky questions, what to do with the output order, and what > field separators are used in the output. All of which (and more) would also be addressed in an obvious way by just supporting --format as I suggested in https://lore.kernel.org/git/211115.86o86lqe3c.gmgdl@xxxxxxxxxxxxxxxxxxx/; don't you think that's a better approach? As noted in https://lore.kernel.org/git/211115.86mtm5saz7.gmgdl@xxxxxxxxxxxxxxxxxxx/ we could start by simply dying if the format is not on a small list of formats we handle, i.e. not implement the strbuf_expand() change to start with. A --show-fields and --hide-fields seems like a rather elaborate interface in lieu of just having a --format. You'd presumably then want a --field-seperator and --name-field-separator (we use SP and TAB for the two, currently), so we've got N option now just to emulate what a --format would do for us.
