<commit-ish> parsing does not recognize @ as HEAD

[KalleOlaviNiemitalo]

With nbgv 3.4.244+c60a07221c, nbgv get-version @ claims "rev-parse produced no commit for @", even though git rev-parse @ treats @ as equivalent to HEAD as documented in git-rev-parse(1).

Microsoft Windows [Version 10.0.19044.1415]
(c) Microsoft Corporation. All rights reserved.

C:\Projects>mkdir commit-ish-parsing

C:\Projects>cd commit-ish-parsing

C:\Projects\commit-ish-parsing>git init
Initialized empty Git repository in C:/Projects/commit-ish-parsing/.git/

C:\Projects\commit-ish-parsing>nbgv install

C:\Projects\commit-ish-parsing>git status
starting fsmonitor-daemon in 'C:/Projects/commit-ish-parsing'
On branch master

No commits yet

Changes to be committed:
  (use "git rm --cached <file>..." to unstage)
        new file:   Directory.Build.props
        new file:   version.json


C:\Projects\commit-ish-parsing>git commit -m "nbgv install"
[master (root-commit) 84f4f71] nbgv install
 2 files changed, 22 insertions(+)
 create mode 100644 Directory.Build.props
 create mode 100644 version.json

C:\Projects\commit-ish-parsing>copy nul dummy
        1 file(s) copied.

C:\Projects\commit-ish-parsing>git add dummy

C:\Projects\commit-ish-parsing>git commit -m dummy
[master c4fd226] dummy
 1 file changed, 0 insertions(+), 0 deletions(-)
 create mode 100644 dummy

C:\Projects\commit-ish-parsing>nbgv get-version
Version:                      1.0.2.64964
AssemblyVersion:              1.0.0.0
AssemblyInformationalVersion: 1.0.2-beta+c4fd226c01
NuGetPackageVersion:          1.0.2-beta
NpmPackageVersion:            1.0.2-beta

C:\Projects\commit-ish-parsing>nbgv get-version @
rev-parse produced no commit for @

C:\Projects\commit-ish-parsing>nbgv get-version HEAD
Version:                      1.0.2.64964
AssemblyVersion:              1.0.0.0
AssemblyInformationalVersion: 1.0.2-beta+c4fd226c01
NuGetPackageVersion:          1.0.2-beta
NpmPackageVersion:            1.0.2-beta

C:\Projects\commit-ish-parsing>git rev-parse @
c4fd226c0169d5f05e10030513c60c376ed565ae

C:\Projects\commit-ish-parsing>nbgv --version
3.4.244+c60a07221c

C:\Projects\commit-ish-parsing>

[KalleOlaviNiemitalo]

Likewise nbgv get-version "HEAD@{2 minutes ago}".

[AArnott]

This would have regressed when we switched from using libgit2 to our own managed git implementation.
I didn't know about @ and we could trivially add support for that. But the @{2 minutes ago} syntax, along with many other variants of the ~ so ^ characters, are probably beyond what we'd want to recreate support for given how rarely they're used with nbgv.

If @GlebChili decides to add support for any or all of these syntaxes in https://github.com/GlebChili/ManagedGitLib, that would be a good reason to consider switching from our private implementation to that one.

[KalleOlaviNiemitalo]

I didn't know about @ and we could trivially add support for that.

Perhaps not so trivially:

$ nbgv get-version @~
Response file not found '~'

get-version:
  Gets the version information for a project.

Usage:
  nbgv get-version [options] [<commit-ish>]

Arguments:
  <commit-ish>    The commit/ref to get the version information for. [default: HEAD]

Options:
  -p, --project <project>      The path to the project or project directory. The default is the current directory.
  --metadata <metadata>        Adds an identifier to the build metadata part of a semantic version. [default: System.String[]]
  -f, --format <json|text>     The format to write the version information. Allowed values are: text, json. The default is text.
  -v, --variable <variable>    The name of just one version property to print to stdout. When specified, the output is always in raw text. Useful in scripts.
  -?, -h, --help               Show help and usage information

I guess the response-file feature comes from System.CommandLine. It does not seem very valuable for nbgv, though.

[KalleOlaviNiemitalo]

(Incidentally, System.CommandLine 2.0.0-beta2.21617.1 is now available. It has some breaking changes as described in dotnet/command-line-api#1537.)

[GlebChili]

I have opened a corresponding issue for ManagedGitLib: GlebChili/ManagedGitLib#6

I will try to implement a full support for the revision specification syntax in question, but I'm not sure how fast can I do it.

[KalleOlaviNiemitalo]

I guess this is somewhat of a duplicate of #572.