Support -b <branch> when cloning (#133)

completion/yadm.bash_completion

@@ -55,7 +55,7 @@ if declare -F _git > /dev/null; then
 
     case "$antepenultimate" in
       clone)
-        COMPREPLY=( $(compgen -W "-f -w --bootstrap --no-bootstrap" -- "$current") )
+        COMPREPLY=( $(compgen -W "-f -w -b --bootstrap --no-bootstrap" -- "$current") )
         return 0
 		  ;;
     esac

test/test_clone.py

@@ -251,6 +251,51 @@ def test_clone_perms(
             f'.{private_type} has not been secured by auto.perms')
 
 
+@pytest.mark.usefixtures('remote')
+@pytest.mark.parametrize('branch', ['master', 'valid', 'invalid'])
+def test_alternate_branch(runner, paths, yadm_y, repo_config, branch):
+    """Test cloning a branch other than master"""
+
+    # add a "valid" branch to the remote
+    os.system(f'GIT_DIR="{paths.remote}" git checkout -b valid')
+    os.system(
+        f'GIT_DIR="{paths.remote}" git commit '
+        f'--allow-empty -m "This branch is valid"')
+
+    # clear out the work path
+    paths.work.remove()
+    paths.work.mkdir()
+
+    remote_url = f'file://{paths.remote}'
+
+    # run the clone command
+    args = ['clone', '-w', paths.work]
+    if branch != 'master':
+        args += ['-b', branch]
+    args += [remote_url]
+    run = runner(command=yadm_y(*args))
+
+    if branch == 'invalid':
+        assert run.failure
+        assert 'ERROR: Clone failed' in run.out
+        assert f"'origin/{branch}' does not exist in {remote_url}" in run.out
+    else:
+        assert successful_clone(run, paths, repo_config)
+
+        # confirm correct Git origin
+        run = runner(
+            command=('git', 'remote', '-v', 'show'),
+            env={'GIT_DIR': paths.repo})
+        assert run.success
+        assert run.err == ''
+        assert f'origin\t{remote_url}' in run.out
+        run = runner(command=yadm_y('show'))
+        if branch == 'valid':
+            assert 'This branch is valid' in run.out
+        else:
+            assert 'Initial commit' in run.out
+
+
 def successful_clone(run, paths, repo_config, expected_code=0):
     """Assert clone is successful"""
     assert run.code == expected_code

test/test_unit_is_valid_branch_name.py

@@ -0,0 +1,40 @@
+"""Unit tests: is_valid_branch_name"""
+import pytest
+
+# Git branches do not allow:
+#  * path component that begins with "."
+#  * double dot
+#  * "~", "^", ":", "\", space
+#  * end with a "/"
+#  * end with ".lock"
+
+
+@pytest.mark.parametrize(
+    'branch, expected', [
+        ('master', 'valid'),
+        ('path/branch', 'valid'),
+        ('path/.branch', 'invalid'),
+        ('path..branch', 'invalid'),
+        ('path~branch', 'invalid'),
+        ('path^branch', 'invalid'),
+        ('path:branch', 'invalid'),
+        ('path\\branch', 'invalid'),
+        ('path branch', 'invalid'),
+        ('path/branch/', 'invalid'),
+        ('branch.lock', 'invalid'),
+    ])
+def test_is_valid_branch_name(runner, yadm, branch, expected):
+    """Test function is_valid_branch_name()"""
+
+    script = f"""
+        YADM_TEST=1 source {yadm}
+        if is_valid_branch_name "{branch}"; then
+            echo valid
+        else
+            echo invalid
+        fi
+    """
+    run = runner(command=['bash'], inp=script)
+    assert run.success
+    assert run.err == ''
+    assert run.out.strip() == expected

yadm

@@ -610,11 +610,20 @@ function clean() {
 function clone() {
 
   DO_BOOTSTRAP=1
+  local branch
+  branch="master"
 
   clone_args=()
   while [[ $# -gt 0 ]] ; do
     key="$1"
     case $key in
+      -b)
+        if ! is_valid_branch_name "$2"; then
+          error_out "You must provide a branch name when using '-b'"
+        fi
+        branch="$2"
+        shift
+      ;;
       --bootstrap) # force bootstrap, without prompt
         DO_BOOTSTRAP=2
       ;;
@@ -634,12 +643,12 @@ function clone() {
   local empty=
   init $empty
 
-  # add the specified remote, and configure the repo to track origin/master
+  # add the specified remote, and configure the repo to track origin/$branch
   debug "Adding remote to new repo"
   "$GIT_PROGRAM" remote add origin "${clone_args[@]}"
-  debug "Configuring new repo to track origin/master"
-  "$GIT_PROGRAM" config branch.master.remote origin
-  "$GIT_PROGRAM" config branch.master.merge refs/heads/master
+  debug "Configuring new repo to track origin/${branch}"
+  "$GIT_PROGRAM" config "branch.${branch}.remote" origin
+  "$GIT_PROGRAM" config "branch.${branch}.merge" "refs/heads/${branch}"
 
   # fetch / merge (and possibly fallback to reset)
   debug "Doing an initial fetch of the origin"
@@ -648,30 +657,36 @@ function clone() {
     rm -rf "$YADM_REPO"
     error_out "Unable to fetch origin ${clone_args[0]}"
   }
+  debug "Verifying '${branch}' is a valid branch to merge"
+  [ -f "${YADM_REPO}/refs/remotes/origin/${branch}" ] || {
+    debug "Removing repo after failed clone"
+    rm -rf "$YADM_REPO"
+    error_out "Clone failed, 'origin/${branch}' does not exist in ${clone_args[0]}"
+  }
   debug "Determining if repo tracks private directories"
   for private_dir in .ssh/ .gnupg/; do
-    found_log=$("$GIT_PROGRAM" log -n 1 origin/master -- "$private_dir" 2>/dev/null)
+    found_log=$("$GIT_PROGRAM" log -n 1 "origin/${branch}" -- "$private_dir" 2>/dev/null)
     if [ -n "$found_log" ]; then
       debug "Private directory $private_dir is tracked by repo"
       assert_private_dirs "$private_dir"
     fi
   done
   [ -n "$DEBUG" ] && display_private_perms "pre-merge"
-  debug "Doing an initial merge of origin/master"
-  "$GIT_PROGRAM" merge origin/master || {
+  debug "Doing an initial merge of origin/${branch}"
+  "$GIT_PROGRAM" merge "origin/${branch}" || {
     debug "Merge failed, doing a reset and stashing conflicts."
-    "$GIT_PROGRAM" reset origin/master
+    "$GIT_PROGRAM" reset "origin/${branch}"
     if cd "$YADM_WORK"; then # necessary because of a bug in Git
       "$GIT_PROGRAM" -c user.name='yadm clone' -c user.email='yadm' stash save Conflicts preserved from yadm clone command 2>&1
       cat <<EOF
 **NOTE**
-  Merging origin/master failed.
+  Merging origin/${branch} failed.
 
-  As a result, yadm did 'reset origin/master', and then
+  As a result, yadm did 'reset origin/${branch}', and then
   stashed the conflicting data.
 
   This likely happened because you had files in \$HOME
-  which conflicted with files tracked by origin/master.
+  which conflicted with files tracked by origin/${branch}.
 
   You can review the stashed conflicts with the
   command 'yadm stash show -p' from within your
@@ -685,15 +700,15 @@ EOF
       DO_BOOTSTRAP=0
       cat <<EOF
 **NOTE**
-  Merging origin/master failed.
-  yadm did 'reset origin/master' instead.
+  Merging origin/${branch} failed.
+  yadm did 'reset origin/${branch}' instead.
 
   yadm did not stash these conflicts beacuse it was unable
   to change to the $YADM_WORK directory.
 
   Please review and resolve any differences appropriately
   If you know what you're doing, and want to overwrite the
-  tracked files, consider 'yadm reset --hard origin/master'
+  tracked files, consider 'yadm reset --hard origin/${branch}'
 EOF
     fi
   }
@@ -1036,6 +1051,17 @@ function version() {
 
 # ****** Utility Functions ******
 
+function is_valid_branch_name() {
+  # Git branches do not allow:
+  #  * path component that begins with "."
+  #  * double dot
+  #  * "~", "^", ":", "\", space
+  #  * end with a "/"
+  #  * end with ".lock"
+  [[ "$1" =~ (\/\.|\.\.|[~^:\\ ]|\/$|\.lock$) ]] && return 1
+  return 0
+}
+
 function query_distro() {
   distro=""
   if command -v "$LSB_RELEASE_PROGRAM" >/dev/null 2>&1; then

yadm.1

@@ -19,13 +19,15 @@ yadm \- Yet Another Dotfiles Manager
 init
 .RB [ -f ]
 .RB [ -w
-.IR directory ]
+.IR dir ]
 
 .B yadm
 .RI clone " url
 .RB [ -f ]
 .RB [ -w
-.IR directory ]
+.IR dir ]
+.RB [ -b
+.IR branch ]
 .RB [ --bootstrap ]
 .RB [ --no-bootstrap ]
 
@@ -146,6 +148,10 @@ but this can be overridden with the
 .BR -w " option.
 yadm can be forced to overwrite an existing repository by providing the
 .BR -f " option.
+If you want to use a branch other than
+.IR origin/master ,
+you can specify it using the
+.BR -b " option.
 By default yadm will ask the user if the bootstrap program should be run (if it
 exists). The options
 .BR --bootstrap " or " --no-bootstrap