Re: rev-list and "ambiguous" IDs

> On Fri, Nov 15, 2019 at 01:12:47AM +0100, Thomas Braun wrote:
> 
>>> That would probably help in a lot of cases, but the argument
>>> against it is that when it goes wrong, it may be quite confusing (so
>>> we're better off with the current message, which punts back to the
>>> user).
>>
>> Just out of curiosity: Is there a use case for inspecting non-commit
>> objects with git log?
> 
> Not that I can think of. You can't even say "--objects" there.
> 
> And indeed, "git log" already prefers commits for disambiguation, since
> d5f6b1d756 (revision.c: the "log" family, except for "show", takes
> committish, 2012-07-02).
> 
> But...
> 
>> If I do (in the git repo)
>>
>> $ git log 1231
>>
>> I get
>>
>> error: short SHA1 1231 is ambiguous
>> hint: The candidates are:
>> hint:   123139fc89 tree
>> hint:   12316a1673 tree
>> hint:   123144fe8a blob
>> fatal: ambiguous argument '1231': unknown revision or path not in the
>> working tree.
>> Use '--' to separate paths from revisions, like this:
>> 'git <command> [<revision>...] -- [<file>...]'
>>
>> with
>> $ git --version
>> git version 2.24.0.windows.2
>>
>> and all of these candidates are no commits.
> 
> ...remember that the disambiguation code is just about preferring one
> object to the other. If the rule in effect doesn't have a preference,
> it's still ambiguous. On my system, "1231" actually _does_ have a
> commit:
> 
>   $ git show 1231
>   error: short SHA1 1231 is ambiguous
>   hint: The candidates are:
>   hint:   12319e3bf2 commit 2017-03-25 - Merge 'git-gui-add-2nd-line' into HEAD
>   hint:   123139fc89 tree
>   hint:   12315b58b8 tree
>   hint:   12316a1673 tree
>   hint:   12317ab2d9 tree
>   hint:   123193f802 tree
>   hint:   123144fe8a blob
>   fatal: ambiguous argument '1231': unknown revision or path not in the working tree.
>   Use '--' to separate paths from revisions, like this:
>   'git <command> [<revision>...] -- [<file>...]'
> 
> That's ambiguous because git-show can handle trees and blobs, too. But
> if I feed that sha1 to git-log:
> 
>   $ git log --oneline -1 1231
>   12319e3bf2 Merge 'git-gui-add-2nd-line' into HEAD
> 
> it's perfectly fine, because git-log knows to disambiguate the commit.
> But if I choose another prefix that has no commits at all, it's
> ambiguous under either, because the "committish" rule has no way to
> decide:
> 
>   $ git show abcd2
>   error: short SHA1 abcd2 is ambiguous
>   hint: The candidates are:
>   hint:   abcd22f55e tree
>   hint:   abcd238df0 tree
>   hint:   abcd2b1cc8 blob
>   
>   $ git log abcd2
>   error: short SHA1 abcd2 is ambiguous
>   hint: The candidates are:
>   hint:   abcd22f55e tree
>   hint:   abcd238df0 tree
>   hint:   abcd2b1cc8 blob