git log -- <old path> not working

Ville Syrjälä· Jun 15, 2020, 21:25 UTC · lore

Hi,

Just ran into a strange case with the Linux kernel repo when trying to look up the history for a file that was later renamed.

$ git log -- drivers/acpi/configfs.c -> nothing

$ git log --follow -- drivers/acpi/configfs.c $ git log --full-history -- drivers/acpi/configfs.c -> works

First time I've seen this fail. Expected behaviour for some reason, or a bug?

$ git --version git version 2.26.2

-- 
Ville Syrjälä
Intel

Junio C Hamano· Jun 17, 2020, 20:18 UTC · re: Ville Syrjälä · lore

Re: git log -- <old path> not working

Ville Syrjälä <ville.syrjala@linux.intel.com> writes:

Show 9 quoted lines

> $ git log -- drivers/acpi/configfs.c
> -> nothing
>
> $ git log --follow -- drivers/acpi/configfs.c
> $ git log --full-history -- drivers/acpi/configfs.c
> -> works
>
> First time I've seen this fail. Expected behaviour for
> some reason, or a bug?

Expected.

In a history is branchy and mergy,

    ---O---o---o---o---o---M---x
        \                 /
         o---A---o---B---o

where A, B and possibly M made changes to PATH,

    $ git log X -- PATH

may show nothing if the PATH at O and M are identical. This is described in "History Simplification" section of "git log --help"