pmbootstrap pull: new action (!1848)

Add a shortcut for "git pull --ff-only" in all repositories cloned by
pmbootstrap (currently pmaports and aports_upstream, new pmdevices
repository coming soon).

'pmbootstrap pull' will only update the repositories, if:
* they are on an officially supported branch (e.g. master)
* the history is not conflicting (fast-forward is possible)
* the git workdirs are clean

Otherwise it shows the user a descriptive message about what to do. The
list of supported branches is only "master" right now, and will be
extended in later commits, so we can have a stable branch for pmaports
based on Alpine's releases. More about that in the project direction
2020 issue.

Closes: #1858

test/test_helpers_git.py

@@ -1,5 +1,5 @@
 """
-Copyright 2019 Oliver Smith
+Copyright 2020 Oliver Smith
 
 This file is part of pmbootstrap.
 
@@ -20,12 +20,14 @@ along with pmbootstrap.  If not, see <http://www.gnu.org/licenses/>.
 import os
 import sys
 import pytest
+import shutil
 
 # Import from parent directory
 sys.path.insert(0, os.path.realpath(
     os.path.join(os.path.dirname(__file__) + "/..")))
 import pmb.helpers.git
 import pmb.helpers.logging
+import pmb.helpers.run
 
 
 @pytest.fixture
@@ -46,3 +48,157 @@ def test_get_path(args):
 
     assert func(args, "aports_upstream") == "/wrk/cache_git/aports_upstream"
     assert func(args, "pmaports") == "/tmp/pmaports"
+
+
+def test_can_fast_forward(args, tmpdir):
+    tmpdir = str(tmpdir)
+    func = pmb.helpers.git.can_fast_forward
+    branch_origin = "fake-branch-origin"
+
+    def run_git(git_args):
+        pmb.helpers.run.user(args, ["git"] + git_args, tmpdir, "stdout")
+
+    # Create test git repo
+    run_git(["init", "."])
+    run_git(["commit", "--allow-empty", "-m", "commit on master"])
+    run_git(["checkout", "-b", branch_origin])
+    run_git(["commit", "--allow-empty", "-m", "commit on branch_origin"])
+    run_git(["checkout", "master"])
+
+    # Can fast-forward
+    assert func(args, tmpdir, branch_origin) is True
+
+    # Can't fast-forward
+    run_git(["commit", "--allow-empty", "-m", "commit on master #2"])
+    assert func(args, tmpdir, branch_origin) is False
+
+    # Git command fails
+    with pytest.raises(RuntimeError) as e:
+        func(args, tmpdir, "invalid-branch")
+    assert str(e.value).startswith("Unexpected exit code")
+
+
+def test_clean_worktree(args, tmpdir):
+    tmpdir = str(tmpdir)
+    func = pmb.helpers.git.clean_worktree
+
+    def run_git(git_args):
+        pmb.helpers.run.user(args, ["git"] + git_args, tmpdir, "stdout")
+
+    # Create test git repo
+    run_git(["init", "."])
+    run_git(["commit", "--allow-empty", "-m", "commit on master"])
+
+    assert func(args, tmpdir) is True
+    pmb.helpers.run.user(args, ["touch", "test"], tmpdir)
+    assert func(args, tmpdir) is False
+
+
+def test_get_upstream_remote(args, monkeypatch, tmpdir):
+    tmpdir = str(tmpdir)
+    func = pmb.helpers.git.get_upstream_remote
+    name_repo = "test"
+
+    # Override get_path()
+    def get_path(args, name_repo):
+        return tmpdir
+    monkeypatch.setattr(pmb.helpers.git, "get_path", get_path)
+
+    # Override pmb.config.git_repos
+    url = "https://postmarketos.org/get-upstream-remote-test.git"
+    git_repos = {"test": url}
+    monkeypatch.setattr(pmb.config, "git_repos", git_repos)
+
+    def run_git(git_args):
+        pmb.helpers.run.user(args, ["git"] + git_args, tmpdir, "stdout")
+
+    # Create git repo
+    run_git(["init", "."])
+    run_git(["commit", "--allow-empty", "-m", "commit on master"])
+
+    # No upstream remote
+    with pytest.raises(RuntimeError) as e:
+        func(args, name_repo)
+    assert "could not find remote name for URL" in str(e.value)
+
+    run_git(["remote", "add", "hello", url])
+    assert func(args, name_repo) == "hello"
+
+
+def test_pull_non_existing(args):
+    assert pmb.helpers.git.pull(args, "non-existing-repo-name") == 1
+
+
+def test_pull(args, monkeypatch, tmpdir):
+    """ Test pmb.helpers.git.pull """
+    # --- PREPARATION: git repos ---
+    # Prepare three git repos:
+    # * local: like local clone of pmaports.git
+    # * remote: emulate a remote repository, that we can add to "local", so we
+    #           can pass the tracking-remote tests in pmb.helpers.git.pull
+    # * remote2: unexpected remote, that pmbootstrap can complain about
+    path_local = str(tmpdir) + "/local"
+    path_remote = str(tmpdir) + "/remote"
+    path_remote2 = str(tmpdir) + "/remote2"
+    os.makedirs(path_local)
+    os.makedirs(path_remote)
+    os.makedirs(path_remote2)
+
+    def run_git(git_args, path=path_local):
+        pmb.helpers.run.user(args, ["git"] + git_args, path, "stdout")
+
+    # Remote repos
+    run_git(["init", "."], path_remote)
+    run_git(["commit", "--allow-empty", "-m", "commit: remote"], path_remote)
+    run_git(["init", "."], path_remote2)
+    run_git(["commit", "--allow-empty", "-m", "commit: remote2"], path_remote2)
+
+    # Local repo (with master -> origin2/master)
+    run_git(["init", "."])
+    run_git(["remote", "add", "-f", "origin", path_remote])
+    run_git(["remote", "add", "-f", "origin2", path_remote2])
+    run_git(["checkout", "-b", "master", "--track", "origin2/master"])
+
+    # --- PREPARATION: function overrides ---
+    # get_path()
+    def get_path(args, name_repo):
+        return path_local
+    monkeypatch.setattr(pmb.helpers.git, "get_path", get_path)
+
+    # get_upstream_remote()
+    def get_u_r(args, name_repo):
+        return "origin"
+    monkeypatch.setattr(pmb.helpers.git, "get_upstream_remote", get_u_r)
+
+    # --- TEST RETURN VALUES ---
+    # Not on official branch
+    func = pmb.helpers.git.pull
+    name_repo = "test"
+    run_git(["checkout", "-b", "inofficial-branch"])
+    assert func(args, name_repo) == -1
+
+    # Workdir is not clean
+    run_git(["checkout", "master"])
+    shutil.copy(__file__, path_local + "/test.py")
+    assert func(args, name_repo) == -2
+    os.unlink(path_local + "/test.py")
+
+    # Tracking different remote
+    assert func(args, name_repo) == -3
+
+    # Let master track origin/master
+    run_git(["checkout", "-b", "temp"])
+    run_git(["branch", "-D", "master"])
+    run_git(["checkout", "-b", "master", "--track", "origin/master"])
+
+    # Already up to date
+    assert func(args, name_repo) == 2
+
+    # Can't fast-forward
+    run_git(["commit", "--allow-empty", "-m", "test"])
+    assert func(args, name_repo) == -4
+
+    # Fast-forward successfully
+    run_git(["reset", "--hard", "origin/master"])
+    run_git(["commit", "--allow-empty", "-m", "new"], path_remote)
+    assert func(args, name_repo) == 0