[PATCH v4 0/1] making --set-upstream have default arguments

Often developers want to set a remote branch (i.e. upstream branch) for the local branch according to their `push.default` settings. For example, beginners often (may be most of the beginners) run

	git push -u origin <current_branch_name>

If the `push.default` configuration is set, people may want to set the upstream to that branch that satisfies the `push.default` configuration. For example, if the `push.default` is set to 'current', developer may want to do like this -

	git push -u <default_repo> <current_branch>

So, it would be great if 'git push -u' (i.e. without <repo> and <refspec>) by default do this. If `push.default` is not set or has a value other than 'matching', it would do this -

	git push -u <default_repo> <current_branch>

And for `push.default`= 'matching', it would set all the remote maching branch as upstream of their respective matching local branches. E.g. if 'branch1' and 'branch2' branches both exist in the local as well as remote repo, 'git push -u' would set the remote 'branch1' as the upstream of local 'branch1' branch and remote 'branch2' branch would be set as the upstream of local 'branch2' branch.

Note, 'git push -u' for push.default=matching, already works. 

This patch series addresses this.

In v0: argumentless 'git push -u' was blindly passing default remote name and current branch's name as argv[0] and argv[1] respectively. This was affecting `push.default` setting.

From v1: The default remote is still used for the <repository> value. But <refspec> depends on the current push configurations. If `push.default`='matching', it pushes to the upstream as it should and sets upstream respectively. For other values of 'push.default', it pushes to the remote branch with the same name as the current branch and sets that branch as the upstream.

In v2 and v3: various test cases were added and improved

In current version: tests for 'git push -u' with other options are added. This includes '-f', '--prune', '-d', '--mirror'.

Abhradeep Chakraborty (1):
  push: make 'set-upstream' have dafault arguments

 Documentation/git-push.txt |  10 +++
 builtin/push.c             |  11 +++-
 t/t5523-push-upstream.sh   | 125 +++++++++++++++++++++++++++++++++++++
 3 files changed, 144 insertions(+), 2 deletions(-)

Range-diff against v3:
1:  64655de6ca ! 1:  d154c7d1f6 push: make '-u' have default arguments
    @@ Metadata
     Author: Abhradeep Chakraborty <chakrabortyabhradeep79@gmail.com>
     
      ## Commit message ##
    -    push: make '-u' have default arguments
    +    push: make 'set-upstream' have dafault arguments
     
         "git push -u" (set-upstream) requires where to push to and what
         to push.  Often people push only the current branch to update
    @@ t/t5523-push-upstream.sh: test_expect_success 'push -u :topic_2' '
     +	test_config remote.pushDefault upstream
     +}
     +
    ++check_empty_config() {
    ++	test_expect_code 1 git config "branch.$1.remote" &&
    ++	test_expect_code 1 git config "branch.$1.merge"
    ++}
    ++
     +for i in simple current upstream nothing
     +do
     +	test_expect_success 'push -u with push.default=$i' '
    @@ t/t5523-push-upstream.sh: test_expect_success 'push -u :topic_2' '
     +		git push -u &&
     +		check_config main upstream refs/heads/main
     +	'
    ++
    ++	test_expect_success 'push -u -f with push.default=$i' '
    ++		default_u_setup $i &&
    ++		git push -u -f &&
    ++		check_config main upstream refs/heads/main
    ++	'
     +done
     +
    -+check_empty_config() {
    -+	test_expect_code 1 git config "branch.$1.remote" &&
    -+	test_expect_code 1 git config "branch.$1.merge"
    -+}
    ++for i in simple current upstream nothing matching
    ++do
    ++	test_expect_success 'push -u --prune with push.default=$i' '
    ++		default_u_setup $i &&
    ++		git push upstream main:test_u215 &&
    ++		git push -u --prune >out &&
    ++		check_config main upstream refs/heads/main &&
    ++		test_i18ngrep "[deleted]" out &&
    ++		test_i18ngrep ! "Branch '"'"'test_u215'"'"' set up to track" out
    ++	'
    ++
    ++	test_expect_success 'push -u --mirror with push.default=$i' '
    ++		default_u_setup $i &&
    ++		test_might_fail git branch mirror1 &&
    ++		test_might_fail git branch mirror2 &&
    ++		git push -u --mirror &&
    ++		check_config main upstream  refs/heads/main &&
    ++		check_config mirror1 upstream refs/heads/mirror1 &&
    ++		check_config mirror2 upstream refs/heads/mirror2
    ++	'
    ++done
     +
    -+test_expect_success 'push -u with push.default=matching' '
    -+	default_u_setup matching &&
    -+	git branch test_u &&
    -+	git branch test_u2 &&
    -+	git push upstream main:test_u2 &&
    -+	git push -u &&
    -+	check_config main upstream refs/heads/main &&
    -+	check_config test_u2 upstream refs/heads/test_u2 &&
    -+	check_empty_config test_u
    ++for i in '' '-f'
    ++do
    ++
    ++	test_expect_success 'push -u $i with push.default=matching' '
    ++		default_u_setup matching &&
    ++		test_might_fail git branch test_u &&
    ++		test_might_fail git branch test_u2 &&
    ++		git push upstream main:test_u2 &&
    ++		git push -u $i &&
    ++		check_config main upstream refs/heads/main &&
    ++		check_config test_u2 upstream refs/heads/test_u2 &&
    ++		check_empty_config test_u
    ++	'
    ++done
    ++
    ++test_expect_success 'push -u -d will fail' '
    ++	git checkout main &&
    ++	test_might_fail git branch --unset-upstream &&
    ++	test_must_fail git push -u -d
     +'
     +
     +test_expect_success 'push -u --dry-run' '