[v3,0/2] rev-parse options for absolute or relative paths

Message

brian m. carlson Nov. 27, 2020, 11:19 p.m. UTC

There are a bunch of different situations in which one would like to
have an absolute and canonical or a relative path from Git.  In many of
these cases, these values are already available from git rev-parse, but
some values only come in one form or another.

Many operating systems, such as macOS, lack a built-in realpath command
that can canonicalize paths properly, and additionally some programming
languages, like Go, currently do as well.  It's therefore helpful for us
to provide a generic way to request that a path is fully canonicalized
before using it.  Since users may wish for a relative path, we can
provide one of those as well.

The primary impetus for this was Git LFS, which needs paths to be
canonicalized in the same way as Git in order to function correctly.
See https://github.com/git-lfs/git-lfs/issues/4012 for more details.

Changes from v2:

* Incorporate multiple missing segment support into the strbuf_realpath
  code.
* Switch some invocations to use DEFAULT_UNMODIFIED, which should not
  result in a change in behavior.
* Rebase, resolving some conflicts.

Changes from v1:

* Add a function to handle missing trailing components when
  canonicalizing paths and use it.
* Improve commit messages.
* Fix broken && chain.
* Fix situation where relative paths are not relative.

brian m. carlson (2):
  abspath: add a function to resolve paths with missing components
  rev-parse: add option for absolute or relative path formatting

 Documentation/git-rev-parse.txt |  71 +++++++++++++---------
 abspath.c                       |  33 +++++++++-
 builtin/rev-parse.c             | 104 ++++++++++++++++++++++++++++----
 cache.h                         |   2 +
 t/t1500-rev-parse.sh            |  57 ++++++++++++++++-
 5 files changed, 223 insertions(+), 44 deletions(-)

Comments

Johannes Schindelin Dec. 2, 2020, 1:12 p.m. UTC | #1

Hi brian,

On Fri, 27 Nov 2020, brian m. carlson wrote:

> There are a bunch of different situations in which one would like to
> have an absolute and canonical or a relative path from Git.  In many of
> these cases, these values are already available from git rev-parse, but
> some values only come in one form or another.
>
> Many operating systems, such as macOS, lack a built-in realpath command
> that can canonicalize paths properly, and additionally some programming
> languages, like Go, currently do as well.  It's therefore helpful for us
> to provide a generic way to request that a path is fully canonicalized
> before using it.  Since users may wish for a relative path, we can
> provide one of those as well.
>
> The primary impetus for this was Git LFS, which needs paths to be
> canonicalized in the same way as Git in order to function correctly.
> See https://github.com/git-lfs/git-lfs/issues/4012 for more details.

Sounds good!

I offered a step back that would allow us to do without
`count_dir_separators()` (or `count_components()`) altogether.

Otherwise, this patch series still looks good to me.

Thanks,
Dscho

>
> Changes from v2:
>
> * Incorporate multiple missing segment support into the strbuf_realpath
>   code.
> * Switch some invocations to use DEFAULT_UNMODIFIED, which should not
>   result in a change in behavior.
> * Rebase, resolving some conflicts.
>
> Changes from v1:
>
> * Add a function to handle missing trailing components when
>   canonicalizing paths and use it.
> * Improve commit messages.
> * Fix broken && chain.
> * Fix situation where relative paths are not relative.
>
> brian m. carlson (2):
>   abspath: add a function to resolve paths with missing components
>   rev-parse: add option for absolute or relative path formatting
>
>  Documentation/git-rev-parse.txt |  71 +++++++++++++---------
>  abspath.c                       |  33 +++++++++-
>  builtin/rev-parse.c             | 104 ++++++++++++++++++++++++++++----
>  cache.h                         |   2 +
>  t/t1500-rev-parse.sh            |  57 ++++++++++++++++-
>  5 files changed, 223 insertions(+), 44 deletions(-)
>
>