Most time, when invoking `git.OpenRepository`, `objectFormat` will not
be used, so it's a waste to invoke commandline to get the object format.
This PR make it a lazy operation, only invoke that when necessary.

Fixes #29101
Related #29298

Discard all read data to prevent misinterpreting existing data. Some
discard calls were missing in error cases.

---------

Co-authored-by: yp05327 <576951401@qq.com>

The 4 functions are duplicated, especially as interface methods. I think
we just need to keep `MustID` the only one and remove other 3.

```
MustID(b []byte) ObjectID
MustIDFromString(s string) ObjectID
NewID(b []byte) (ObjectID, error)
NewIDFromString(s string) (ObjectID, error)
```

Introduced the new interfrace method `ComputeHash` which will replace
the interface `HasherInterface`. Now we don't need to keep two
interfaces.

Reintroduced `git.NewIDFromString` and `git.MustIDFromString`. The new
function will detect the hash length to decide which objectformat of it.
If it's 40, then it's SHA1. If it's 64, then it's SHA256. This will be
right if the commitID is a full one. So the parameter should be always a
full commit id.

@AdamMajer Please review.

Refactor Hash interfaces and centralize hash function. This will allow
easier introduction of different hash function later on.

This forms the "no-op" part of the SHA256 enablement patch.

Fix #13485.

Co-authored-by: delvh <dev.lh@web.de>
Co-authored-by: Lauris BH <lauris@nix.lv>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

Change all license headers to comply with REUSE specification.

Fix #16132

Co-authored-by: flynnnnnnnnnn <flynnnnnnnnnn@github>
Co-authored-by: John Olheiser <john.olheiser@gmail.com>

Go 1.17 and later use modern `//go:build` constraints, the old `// +build:` constraints should be removed.

* fix npe

* rm gitRepo from Tag

This PR registers requests with the process manager and manages hierarchy within the processes.

Git repos are then associated with a context, (usually the request's context) - with sub commands using this context as their base context.

Signed-off-by: Andrew Thornton <art27@cantab.net>

The io/ioutil package has been deprecated as of Go 1.16, see
https://golang.org/doc/go1.16#ioutil. This commit replaces the existing
io/ioutil functions with their new definitions in io and os packages.

Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

* Add bundle download

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Fix fmt

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Fix build tags

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Download specific commit

Signed-off-by: jolheiser <john.olheiser@gmail.com>

Use common git cat-file --batch and git cat-file --batch-check to
significantly reduce calls to git.
    
Signed-off-by: Andrew Thornton <art27@cantab.net>

* Fix git.parseTagData()
close #14092

* Add Test

* add message to test

* limit readers

* git tag -m trims and terminates with a newline

Co-authored-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: 6543 <6543@obermui.de>

* Move last commit cache back into modules/git

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Remove go-git from the interface for last commit cache

Signed-off-by: Andrew Thornton <art27@cantab.net>

* move cacheref to last_commit_cache

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Remove go-git from routers/private/hook

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Move FindLFSFiles to pipeline

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Make no-go-git variants

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Submodule RefID

Signed-off-by: Andrew Thornton <art27@cantab.net>

* fix issue with GetCommitsInfo

Signed-off-by: Andrew Thornton <art27@cantab.net>

* fix GetLastCommitForPaths

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Improve efficiency

Signed-off-by: Andrew Thornton <art27@cantab.net>

* More efficiency

Signed-off-by: Andrew Thornton <art27@cantab.net>

* even faster

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Reduce duplication

* As per @lunny

Signed-off-by: Andrew Thornton <art27@cantab.net>

* attempt to fix drone

Signed-off-by: Andrew Thornton <art27@cantab.net>

* fix test-tags

Signed-off-by: Andrew Thornton <art27@cantab.net>

* default to use no-go-git variants and add gogit build tag

Signed-off-by: Andrew Thornton <art27@cantab.net>

* placate lint

Signed-off-by: Andrew Thornton <art27@cantab.net>

* as per @6543

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>