release: v0.9.9 [skip ci]

.taskid

@@ -1 +1 @@
-DEVX-21
+DEVX-30

CHANGELOG.md

@@ -2,6 +2,59 @@
 
 All notable changes to this project will be documented in this file.
 
+## [0.9.9] - 2026-06-24
+
+### Bug Fixes
+
+- Use DOCKER_HOST env var in is_docker_ready + scan all rootless sockets
+- Prefer branch name for task ID extraction + strip heads/ prefix in release
+- Filter non-version tags in release verification
+- Use explicit refspecs for git push to avoid tag/branch ambiguity
+
+## [0.9.8] - 2026-06-24
+
+### Bug Fixes
+
+- Use DOCKER_HOST env var in is_docker_ready + scan all rootless sockets
+
+## [0.9.7] - 2026-06-24
+
+### Bug Fixes
+
+- Add rootless socket fallback and GITHUB_ENV export
+
+## [0.9.6] - 2026-06-24
+
+### Bug Fixes
+
+- Add Docker socket diagnostics to start_docker
+- Add Docker socket diagnostics to start_docker
+
+## [0.9.5] - 2026-06-24
+
+### Bug Fixes
+
+- Use host Docker socket with DOCKER_HOST fallback to local dockerd
+- Use host Docker socket with DOCKER_HOST fallback to local dockerd
+
+## [0.9.4] - 2026-06-24
+
+### Bug Fixes
+
+- Use separate Docker socket for DinD in CI
+
+## [0.9.3] - 2026-06-24
+
+### Bug Fixes
+
+- Use tempfile for dockerd log to fix CI permission error
+
+## [0.9.2] - 2026-06-24
+
+### Bug Fixes
+
+- Use vfs storage driver for Docker-in-Docker in CI
+
 ## [0.9.1] - 2026-06-23
 
 ### Bug Fixes

src/devx/__init__.py

@@ -1,3 +1,3 @@
 """devx — reusable development and CI/CD tools for oblachno-oss projects."""
 
-__version__ = "0.9.1"
+__version__ = "0.9.9"

src/devx/ci/auto_merge.py

@@ -63,20 +63,22 @@ def run_cmd(args: list[str], check: bool = True) -> subprocess.CompletedProcess[
 
 
 def read_taskid(branch: str) -> str:
-    """Read task ID from .taskid file, falling back to branch name extraction.
+    """Read task ID from branch name, falling back to .taskid file.
 
-    The .taskid file is a simple text file containing just the task ID
-    (e.g., ``DEVX-60``).  If the file doesn't exist, extract from the
-    branch name as a backwards-compatibility fallback.
+    The branch name is the primary source of truth for the task ID
+    (e.g., ``DEVX-31-fix-foo`` → ``DEVX-31``).  The ``.taskid`` file
+    is a legacy fallback for branches without a task ID prefix.
     """
+    branch_task_id = extract_task_id(branch)
+    if branch_task_id:
+        return branch_task_id
+    # Fallback: read from .taskid file
     path = Path(TASKID_FILE)
     if path.exists():
         task_id = path.read_text(encoding="utf-8").strip()
         if task_id:
             return task_id
-    # Fallback: extract from branch name
-    match = TASK_ID_RE.search(branch)
-    return match.group(0) if match else ""
+    return ""
 
 
 def extract_task_id(branch: str) -> str:

src/devx/ci/release.py

@@ -136,10 +136,14 @@ def verify_tag_consistency() -> list[str]:
     """
     errors: list[str] = []
     tags = get_all_tags()
-    # Sort oldest first to identify the first tag
-    sorted_tags = sorted(tags, key=lambda t: [int(x) for x in t.lstrip("v").split(".")])
+    # Filter to version tags (vX.Y.Z) and sort oldest first
+    version_tags = [t for t in tags if re.match(r"^v\d+\.\d+\.\d+$", t)]
+    sorted_tags = sorted(version_tags, key=lambda t: [int(x) for x in t.lstrip("v").split(".")])
     first_tag = sorted_tags[0] if sorted_tags else None
     for tag in tags:
+        # Skip non-version tags (e.g., branch names like "master")
+        if not re.match(r"^v\d+\.\d+\.\d+$", tag):
+            continue
         tag_version = tag.lstrip("v")
         commit_version = get_commit_version(tag)
         if commit_version is None:
@@ -340,14 +344,14 @@ def create_and_push_tag(new_version: str, changelog: str, dry_run: bool) -> bool
         click.echo(_("Tag {tag} already exists and points to HEAD. Skipping creation.", tag=tag))
         if not dry_run:
             # Ensure the existing tag is pushed
-            run_cmd(["git", "push", "origin", tag], check=False)
+            run_cmd(["git", "push", "origin", f"refs/tags/{tag}"], check=False)
         return False
     tag_msg = f"Release v{new_version}\n\n{changelog}"
     if dry_run:
         click.echo(_("[dry-run] Would create tag: {tag}", tag=tag))
         return True
     run_cmd(["git", "tag", "-a", tag, "-m", tag_msg])
-    run_cmd(["git", "push", "origin", tag])
+    run_cmd(["git", "push", "origin", f"refs/tags/{tag}"])
     return True
 
 
@@ -478,7 +482,7 @@ def verify_alignment() -> int:
     )
     if result.returncode == 0 and result.stdout.strip():
         all_release_commits = result.stdout.strip().split("\n")
-        all_tags_set = {t.lstrip("v") for t in get_all_tags()}
+        all_tags_set = {t.lstrip("v") for t in get_all_tags() if re.match(r"^v\d+\.\d+\.\d+$", t)}
         truly_untagged: list[str] = []
         duplicates: list[str] = []
         for line in all_release_commits:
@@ -547,6 +551,8 @@ def main(dry_run: bool, skip_tests: bool, verify: bool) -> None:
 
     # Ensure we're on master (skip this check in dry-run mode for PR validation)
     branch = run_cmd(["git", "rev-parse", "--abbrev-ref", "HEAD"]).stdout.strip()
+    # Some git versions return "heads/master" instead of "master"
+    branch = branch.removeprefix("heads/")
     if branch != "master" and not dry_run:
         raise click.ClickException(_("Release must be run on master, currently on '{branch}'.", branch=branch))
     if branch != "master" and dry_run:
@@ -694,7 +700,8 @@ def main(dry_run: bool, skip_tests: bool, verify: bool) -> None:
         # Pull --rebase before push to handle the case where master
         # advanced between checkout and commit (e.g., another merge).
         run_cmd(["git", "pull", "--rebase", "origin", "master"], check=False)
-        run_cmd(["git", "push", "origin", "master"])
+        # Use refs/heads/master to avoid ambiguity with a 'master' tag
+        run_cmd(["git", "push", "origin", "refs/heads/master:refs/heads/master"])
         click.echo(_("Pushed release commit to master."))
     else:
         click.echo(_("Skipping commit push — no staged changes."))

src/devx/molecule/molecule_ci_guard.py

@@ -321,6 +321,17 @@ def cli(pairs: tuple[str, ...], junit_output: str | None, roles_root: Path | Non
 
             click.echo(_("PASSED: {pair}", pair=pair))
 
+            # Prune Docker data between scenarios to prevent disk exhaustion
+            # in Docker-in-Docker molecule containers (each scenario pulls
+            # hundreds of MB of images that accumulate across pairs).
+            with contextlib.suppress(subprocess.SubprocessError, OSError):
+                subprocess.run(  # nosec B603, B607
+                    ["docker", "system", "prune", "-af", "--volumes"],
+                    check=False,
+                    capture_output=True,
+                    timeout=60,
+                )
+
         click.echo(_("All molecule tests passed."))
         if junit_output:
             write_junit_report(junit_output, testcases, current_index)

src/devx/molecule/start_docker.py

@@ -1,10 +1,14 @@
 #!/usr/bin/env python3
-"""Start a Docker daemon inside a CI runner container (Docker-in-Docker).
+"""Ensure Docker is available for molecule tests in CI.
 
 CI runners (e.g. ``gitea/runner-images:ubuntu-latest``) may have the host's
-Docker socket mounted, but molecule needs a local Docker daemon to create
-nested containers. This module always starts ``dockerd`` in the background
-and waits for it to become ready.
+Docker socket mounted. This module verifies Docker is accessible and
+sets ``DOCKER_HOST`` explicitly so molecule's Python docker library
+connects to the same socket as the Docker CLI.
+
+If the host socket is not available, it tries the rootless socket, then
+starts a local ``dockerd`` with the vfs storage driver (requires
+privileged container).
 
 Usage::
 
@@ -13,8 +17,11 @@ Usage::
 
 from __future__ import annotations
 
+import glob
+import os
 import subprocess  # nosec B404
 import sys
+import tempfile
 import time
 
 import click
@@ -22,33 +29,130 @@ import click
 from devx.i18n import _
 
 DEFAULT_TIMEOUT = 30
-DOCKERD_LOG = "/var/log/dockerd.log"
+DOCKER_SOCK = "/var/run/docker.sock"
+# Rootless socket fallback (e.g. /run/user/994/docker.sock)
+ROOTLESS_SOCK = f"/run/user/{os.getuid()}/docker.sock"
 
 
 def is_docker_ready() -> bool:
-    """Check if the Docker daemon is responding."""
+    """Check if Docker daemon is responding on the configured socket."""
+    docker_host = os.environ.get("DOCKER_HOST", f"unix://{DOCKER_SOCK}")
     result = subprocess.run(  # nosec B603 B607
         ["docker", "info"],
         capture_output=True,
         check=False,
+        env={**os.environ, "DOCKER_HOST": docker_host},
     )
     return result.returncode == 0
 
 
-def start_docker_daemon(timeout: int = DEFAULT_TIMEOUT) -> bool:
-    """Start dockerd in the background and wait for it to be ready.
+def _diagnose_socket() -> None:
+    """Print diagnostic info about the Docker socket."""
+    click.echo(f"DOCKER_HOST = {os.environ.get('DOCKER_HOST', '(not set)')}")
+    click.echo(f"Socket path: {DOCKER_SOCK}")
+    click.echo(f"Socket exists: {os.path.exists(DOCKER_SOCK)}")
+    if os.path.exists(DOCKER_SOCK):
+        stat = os.stat(DOCKER_SOCK)
+        click.echo(f"Socket mode: {oct(stat.st_mode)}")
+        click.echo(f"Socket uid: {stat.st_uid}, gid: {stat.st_gid}")
+    # Check if it's a mount point
+    result = subprocess.run(  # nosec B603 B607
+        ["mount"],
+        capture_output=True,
+        check=False,
+        text=True,
+    )
+    docker_mounts = [line for line in result.stdout.splitlines() if "docker" in line.lower()]
+    if docker_mounts:
+        click.echo("Docker-related mounts:")
+        for line in docker_mounts:
+            click.echo(f"  {line}")
+    else:
+        click.echo("No Docker-related mounts found")
+    # Check docker context
+    result = subprocess.run(  # nosec B603 B607
+        ["docker", "context", "ls"],
+        capture_output=True,
+        check=False,
+        text=True,
+    )
+    click.echo(f"Docker contexts:\n{result.stdout}")
+    # Try docker info without DOCKER_HOST
+    result = subprocess.run(  # nosec B603 B607
+        ["docker", "info"],
+        capture_output=True,
+        check=False,
+        text=True,
+    )
+    click.echo(f"docker info (no DOCKER_HOST): rc={result.returncode}")
+    if result.returncode != 0:
+        click.echo(f"  stderr: {result.stderr[:500]}")
+    else:
+        # Print server version and storage driver
+        for line in result.stdout.splitlines():
+            if "Server Version" in line or "Storage Driver" in line or "Docker Root Dir" in line:
+                click.echo(f"  {line.strip()}")
 
-    Always starts a local dockerd even if ``docker info`` succeeds,
-    because the host socket may be mounted but not suitable for
-    molecule's nested container creation.
+
+def start_docker_daemon(timeout: int = DEFAULT_TIMEOUT) -> bool:
+    """Ensure Docker is ready for molecule tests.
+
+    First tries the host socket. If that works, sets ``DOCKER_HOST`` and
+    returns immediately. If not, tries the rootless socket. If neither
+    works, starts a local ``dockerd`` with vfs storage driver (requires
+    privileged container).
 
     Returns ``True`` if Docker is ready, ``False`` if it failed to
     start within the timeout.
     """
-    click.echo(_("Starting Docker daemon..."))
-    log_file = open(DOCKERD_LOG, "w")  # noqa: SIM115
+    # Point Docker CLI and Python library to the socket explicitly
+    os.environ["DOCKER_HOST"] = f"unix://{DOCKER_SOCK}"
+
+    # Diagnose socket state
+    click.echo("--- Docker socket diagnostics ---")
+    _diagnose_socket()
+    click.echo("--- End diagnostics ---")
+
+    # Check if host Docker is already available
+    if is_docker_ready():
+        click.echo(_("Docker daemon already running"))
+        return True
+
+    # Try rootless socket (e.g. /run/user/994/docker.sock)
+    click.echo(f"Trying rootless socket: {ROOTLESS_SOCK}")
+    os.environ["DOCKER_HOST"] = f"unix://{ROOTLESS_SOCK}"
+    if os.path.exists(ROOTLESS_SOCK) and is_docker_ready():
+        click.echo(_("Docker daemon already running"))
+        return True
+
+    # Scan for any rootless sockets at other UIDs
+    for sock in sorted(glob.glob("/run/user/*/docker.sock")):
+        if sock == ROOTLESS_SOCK:
+            continue
+        click.echo(f"Trying alternative rootless socket: {sock}")
+        os.environ["DOCKER_HOST"] = f"unix://{sock}"
+        if is_docker_ready():
+            click.echo(_("Docker daemon already running"))
+            return True
+
+    click.echo(_("Host Docker not available, starting local dockerd..."))
+
+    # Reset DOCKER_HOST to host socket for local dockerd
+    os.environ["DOCKER_HOST"] = f"unix://{DOCKER_SOCK}"
+
+    # Start local dockerd (requires privileged container)
+    log_file = tempfile.NamedTemporaryFile(  # noqa: SIM115
+        mode="w", suffix="dockerd.log", delete=False
+    )
+    click.echo(f"dockerd log: {log_file.name}")
     subprocess.Popen(  # nosec B603 B607
-        ["dockerd"],
+        [
+            "dockerd",
+            "--storage-driver",
+            "vfs",
+            "-H",
+            f"unix://{DOCKER_SOCK}",
+        ],
         stdout=log_file,
         stderr=subprocess.STDOUT,
         start_new_session=True,
@@ -60,7 +164,17 @@ def start_docker_daemon(timeout: int = DEFAULT_TIMEOUT) -> bool:
             return True
         time.sleep(1)
 
+    # Print dockerd log on failure
     click.echo(_("Docker daemon failed to start"))
+    click.echo("--- dockerd log ---")
+    try:
+        with open(log_file.name) as f:
+            log_content = f.read()
+        click.echo(log_content[-3000:] if len(log_content) > 3000 else log_content)
+    except OSError as e:
+        click.echo(f"Could not read log: {e}")
+    click.echo("--- End dockerd log ---")
+
     return False
 
 
@@ -74,6 +188,12 @@ def start_docker_daemon(timeout: int = DEFAULT_TIMEOUT) -> bool:
 def main(timeout: int) -> None:
     """Start Docker daemon for CI molecule tests."""
     if start_docker_daemon(timeout):
+        # Export DOCKER_HOST to GITHUB_ENV for subsequent CI steps
+        github_env = os.environ.get("GITHUB_ENV")
+        if github_env and os.environ.get("DOCKER_HOST"):
+            with open(github_env, "a") as f:
+                f.write(f"DOCKER_HOST={os.environ['DOCKER_HOST']}\n")
+            click.echo(f"Exported DOCKER_HOST={os.environ['DOCKER_HOST']} to GITHUB_ENV")
         sys.exit(0)
     sys.exit(1)
 

src/devx/translations.json

@@ -419,6 +419,13 @@
     "ru": "Created release commit.",
     "zh": "Created release commit."
   },
+  "Docker daemon already running": {
+    "bg": "Докер демонът вече работи",
+    "de": "Docker-Daemon läuft bereits",
+    "en": "Docker daemon already running",
+    "ru": "Демон Docker уже работает",
+    "zh": "Docker 守护进程已在运行"
+  },
   "Docker daemon failed to start": {
     "bg": "Docker daemon failed to start",
     "de": "Docker-Daemon konnte nicht gestartet werden",
@@ -552,6 +559,13 @@
     "ru": "Head branch is behind master. Pulling and rebasing...",
     "zh": "Head branch is behind master. Pulling and rebasing..."
   },
+  "Host Docker not available, starting local dockerd...": {
+    "bg": "Хост Docker не е наличен, стартиране на локален dockerd...",
+    "de": "Host-Docker nicht verfügbar, lokaler dockerd wird gestartet...",
+    "en": "Host Docker not available, starting local dockerd...",
+    "ru": "Хост Docker недоступен, запускается локальный dockerd...",
+    "zh": "主机 Docker 不可用，正在启动本地 dockerd..."
+  },
   "Infrastructure commit (no DEVX-N task ID), skipping Vikunja update: {msg}": {
     "bg": "Инфраструктурен commit (без идентификатор на задача DEVX-N), пропускаме обновяването на Vikunja: {msg}",
     "de": "Infrastruktur-Commit (keine DEVX-N Task-ID), Vikunja-Update wird übersprungen: {msg}",
@@ -930,13 +944,6 @@
     "ru": "Skipping commit push — no staged changes.",
     "zh": "Skipping commit push — no staged changes."
   },
-  "Starting Docker daemon...": {
-    "bg": "Starting Docker daemon...",
-    "de": "Docker-Daemon wird gestartet...",
-    "en": "Starting Docker daemon...",
-    "ru": "Запуск Docker-демона...",
-    "zh": "正在启动 Docker 守护进程..."
-  },
   "Syncing {count} documentation pages to wiki...": {
     "bg": "Syncing {count} documentation pages to wiki...",
     "de": "Syncing {count} documentation pages to wiki...",

tests/unit/test_auto_merge.py

@@ -21,9 +21,16 @@ from devx.exceptions import APIError
 
 
 class TestReadTaskid:
-    def test_reads_from_file(self, tmp_path, monkeypatch) -> None:  # type: ignore[no-untyped-def]
+    def test_prefers_branch_name_over_file(self, tmp_path, monkeypatch) -> None:  # type: ignore[no-untyped-def]
         monkeypatch.chdir(tmp_path)
         (tmp_path / ".taskid").write_text("DEVX-60\n")
+        # Branch name takes priority over .taskid file
+        assert read_taskid("DEVX-19-fix-bug") == "DEVX-19"
+
+    def test_falls_back_to_file_when_no_branch_match(self, tmp_path, monkeypatch) -> None:  # type: ignore[no-untyped-def]
+        monkeypatch.chdir(tmp_path)
+        (tmp_path / ".taskid").write_text("DEVX-60\n")
+        # No task ID in branch name → fall back to .taskid
         assert read_taskid("some-branch") == "DEVX-60"
 
     def test_falls_back_to_branch_name(self, tmp_path, monkeypatch) -> None:  # type: ignore[no-untyped-def]

tests/unit/test_molecule_ci_guard.py

@@ -162,17 +162,26 @@ class TestCli:
 
         with (
             patch("devx.molecule.molecule_ci_guard.subprocess.Popen") as mock_popen,
+            patch("devx.molecule.molecule_ci_guard.subprocess.run") as mock_run,
             patch("time.sleep"),
         ):
             proc = MagicMock()
             proc.poll.return_value = 0
             proc.returncode = 0
             mock_popen.return_value = proc
+            mock_run.return_value = MagicMock(returncode=0)
 
             runner = CliRunner()
             result = runner.invoke(cli, ["default|ubuntu-2204|img:latest|"])
             assert result.exit_code == 0
             assert "All molecule tests passed" in result.output
+            # Verify Docker prune was called between scenarios
+            mock_run.assert_called_once_with(
+                ["docker", "system", "prune", "-af", "--volumes"],
+                check=False,
+                capture_output=True,
+                timeout=60,
+            )
 
     def test_invalid_pair_format_raises(self) -> None:
         """Pair with fewer than 2 parts should raise."""
@@ -324,6 +333,7 @@ class TestCli:
             ),
             patch("devx.molecule.molecule_ci_guard.POLL_INTERVAL", 0.01),
             patch("devx.molecule.molecule_ci_guard.subprocess.Popen") as mock_popen,
+            patch("devx.molecule.molecule_ci_guard.subprocess.run") as mock_run,
             patch("devx.molecule.molecule_ci_guard.get_running_jobs") as mock_get_jobs,
             patch("time.sleep", side_effect=lambda x: real_sleep(0.05)),
         ):
@@ -332,6 +342,7 @@ class TestCli:
             proc.poll.return_value = 0
             proc.returncode = 0
             mock_popen.return_value = proc
+            mock_run.return_value = MagicMock(returncode=0)
 
             runner = CliRunner()
             result = runner.invoke(cli, ["default|ubuntu-2204|img:latest|"])
@@ -536,12 +547,14 @@ class TestCliMultiRole:
 
         with (
             patch("devx.molecule.molecule_ci_guard.subprocess.Popen") as mock_popen,
+            patch("devx.molecule.molecule_ci_guard.subprocess.run") as mock_run,
             patch("time.sleep"),
         ):
             proc = MagicMock()
             proc.poll.return_value = 0
             proc.returncode = 0
             mock_popen.return_value = proc
+            mock_run.return_value = MagicMock(returncode=0)
 
             runner = CliRunner()
             result = runner.invoke(
@@ -560,12 +573,14 @@ class TestCliMultiRole:
 
         with (
             patch("devx.molecule.molecule_ci_guard.subprocess.Popen") as mock_popen,
+            patch("devx.molecule.molecule_ci_guard.subprocess.run") as mock_run,
             patch("time.sleep"),
         ):
             proc = MagicMock()
             proc.poll.return_value = 0
             proc.returncode = 0
             mock_popen.return_value = proc
+            mock_run.return_value = MagicMock(returncode=0)
 
             runner = CliRunner()
             result = runner.invoke(

tests/unit/test_release.py

@@ -270,6 +270,15 @@ class TestVerifyTagConsistency:
         mock_tags.return_value = []
         assert verify_tag_consistency() == []
 
+    @patch("devx.ci.release.get_commit_version")
+    @patch("devx.ci.release.get_all_tags")
+    def test_non_version_tags_ignored(self, mock_tags: MagicMock, mock_cv: MagicMock) -> None:
+        """Non-version tags like 'master' should be skipped, not crash."""
+        mock_tags.return_value = ["v0.2.0", "master", "v0.1.0"]
+        mock_cv.side_effect = ["0.2.0", "0.1.0"]  # only version tags get checked
+        errors = verify_tag_consistency()
+        assert errors == []
+
 
 class TestGetInitVersion:
     def test_returns_version(self, tmp_path, monkeypatch) -> None:
@@ -776,7 +785,7 @@ class TestCreateAndPushTag:
         create_and_push_tag("0.2.0", "changelog", dry_run=False)
         calls = [c.args[0] for c in mock_run_cmd.call_args_list]
         assert ["git", "tag", "-a", "v0.2.0", "-m", "Release v0.2.0\n\nchangelog"] in calls
-        assert ["git", "push", "origin", "v0.2.0"] in calls
+        assert ["git", "push", "origin", "refs/tags/v0.2.0"] in calls
 
     @patch("devx.ci.release.tag_exists", return_value=False)
     @patch("devx.ci.release.run_cmd")
@@ -803,7 +812,7 @@ class TestCreateAndPushTag:
         # Should not create tag, but should ensure it's pushed
         calls = [c.args[0] for c in mock_run_cmd.call_args_list]
         assert ["git", "tag", "-a"] not in [c[:3] for c in calls]
-        assert ["git", "push", "origin", "v0.1.0"] in calls
+        assert ["git", "push", "origin", "refs/tags/v0.1.0"] in calls
 
     @patch("devx.ci.release.get_head_commit", return_value="def456")
     @patch("devx.ci.release.get_tag_commit", return_value="abc123")

tests/unit/test_start_docker.py

@@ -1,89 +1,239 @@
 """Unit tests for devx.molecule.start_docker."""
 
+import os
 from unittest.mock import MagicMock, mock_open, patch
 
 from click.testing import CliRunner
 
-from devx.molecule.start_docker import is_docker_ready, main, start_docker_daemon
+from devx.molecule.start_docker import (
+    DOCKER_SOCK,
+    _diagnose_socket,
+    is_docker_ready,
+    main,
+    start_docker_daemon,
+)
 
 
 class TestIsDockerReady:
     @patch("devx.molecule.start_docker.subprocess.run")
     def test_ready(self, mock_run: MagicMock) -> None:
         mock_run.return_value = MagicMock(returncode=0)
-        assert is_docker_ready() is True
-        mock_run.assert_called_once_with(["docker", "info"], capture_output=True, check=False)
+        with patch.dict("os.environ", {"DOCKER_HOST": f"unix://{DOCKER_SOCK}"}, clear=False):
+            assert is_docker_ready() is True
+        call_kwargs = mock_run.call_args
+        assert call_kwargs.args[0] == ["docker", "info"]
+        assert call_kwargs.kwargs["env"]["DOCKER_HOST"] == f"unix://{DOCKER_SOCK}"
 
     @patch("devx.molecule.start_docker.subprocess.run")
     def test_not_ready(self, mock_run: MagicMock) -> None:
         mock_run.return_value = MagicMock(returncode=1)
         assert is_docker_ready() is False
 
+    @patch("devx.molecule.start_docker.subprocess.run")
+    def test_uses_docker_host_env(self, mock_run: MagicMock) -> None:
+        """Should check the socket specified by DOCKER_HOST env var."""
+        mock_run.return_value = MagicMock(returncode=0)
+        rootless = "unix:///run/user/999/docker.sock"
+        with patch.dict("os.environ", {"DOCKER_HOST": rootless}, clear=False):
+            assert is_docker_ready() is True
+        call_kwargs = mock_run.call_args
+        assert call_kwargs.kwargs["env"]["DOCKER_HOST"] == rootless
+
+
+class TestDiagnoseSocket:
+    @patch("devx.molecule.start_docker.os.stat")
+    @patch("devx.molecule.start_docker.os.path.exists", return_value=True)
+    @patch("devx.molecule.start_docker.subprocess.run")
+    def test_socket_exists(self, mock_run: MagicMock, mock_exists: MagicMock, mock_stat: MagicMock) -> None:
+        mock_stat.return_value = MagicMock(st_mode=0o660, st_uid=0, st_gid=0)
+        mock_run.side_effect = [
+            MagicMock(stdout="/dev/sda1 /var/lib/docker ext4\n", returncode=0, text=""),
+            MagicMock(stdout="default\n", returncode=0, text=""),
+            MagicMock(
+                stdout="Server Version: 29.5.2\nStorage Driver: overlay2\nDocker Root Dir: /var/lib/docker\n",
+                returncode=0,
+                text="",
+            ),
+        ]
+        _diagnose_socket()
+        mock_exists.assert_called_with(DOCKER_SOCK)
+
+    @patch("devx.molecule.start_docker.os.path.exists", return_value=False)
+    @patch("devx.molecule.start_docker.subprocess.run")
+    def test_socket_missing(self, mock_run: MagicMock, mock_exists: MagicMock) -> None:
+        mock_run.side_effect = [
+            MagicMock(stdout="proc on /proc type proc\n", returncode=0, text=""),
+            MagicMock(stdout="default\n", returncode=0, text=""),
+            MagicMock(stdout="", stderr="Cannot connect", returncode=1, text=""),
+        ]
+        _diagnose_socket()
+        mock_exists.assert_called_with(DOCKER_SOCK)
+
 
 class TestStartDockerDaemon:
-    @patch("devx.molecule.start_docker.time.sleep")
+    @patch("devx.molecule.start_docker._diagnose_socket")
+    @patch("devx.molecule.start_docker.is_docker_ready", return_value=True)
+    def test_host_socket_available(self, mock_ready: MagicMock, mock_diag: MagicMock) -> None:
+        """Should return immediately if host Docker is available."""
+        assert start_docker_daemon(timeout=5) is True
+        mock_ready.assert_called_once()
+        mock_diag.assert_called_once()
+
+    @patch("devx.molecule.start_docker._diagnose_socket")
+    @patch("devx.molecule.start_docker.os.path.exists", return_value=True)
     @patch("devx.molecule.start_docker.is_docker_ready")
-    @patch("devx.molecule.start_docker.subprocess.Popen")
-    @patch("builtins.open", new_callable=mock_open)
-    def test_starts_successfully(
-        self,
-        mock_file: MagicMock,
-        mock_popen: MagicMock,
-        mock_ready: MagicMock,
-        mock_sleep: MagicMock,
+    def test_rootless_socket_available(
+        self, mock_ready: MagicMock, mock_exists: MagicMock, mock_diag: MagicMock
     ) -> None:
-        # First loop iteration: dockerd not ready yet. Second: ready.
+        """Should use rootless socket if host socket fails."""
+        # First check (host) fails, second check (rootless) succeeds
         mock_ready.side_effect = [False, True]
+        with patch("devx.molecule.start_docker.glob.glob", return_value=[]):
+            assert start_docker_daemon(timeout=5) is True
+
+    @patch("devx.molecule.start_docker._diagnose_socket")
+    @patch("devx.molecule.start_docker.os.path.exists", return_value=True)
+    @patch("devx.molecule.start_docker.is_docker_ready")
+    def test_alt_rootless_socket_found(
+        self, mock_ready: MagicMock, mock_exists: MagicMock, mock_diag: MagicMock
+    ) -> None:
+        """Should find rootless socket at a different UID via glob scan."""
+        # Host fails, own rootless fails, alt rootless succeeds
+        mock_ready.side_effect = [False, False, True]
+        alt_sock = "/run/user/999/docker.sock"
+        with patch("devx.molecule.start_docker.glob.glob", return_value=[alt_sock]):
+            assert start_docker_daemon(timeout=5) is True
+
+    @patch("devx.molecule.start_docker._diagnose_socket")
+    @patch("devx.molecule.start_docker.os.path.exists", return_value=True)
+    @patch("devx.molecule.start_docker.is_docker_ready")
+    def test_alt_rootless_socket_skips_own(
+        self, mock_ready: MagicMock, mock_exists: MagicMock, mock_diag: MagicMock
+    ) -> None:
+        """Should skip the own rootless socket in glob scan (already tried)."""
+        # Host fails, own rootless fails, alt rootless also fails, dockerd fails
+        mock_ready.side_effect = [False, False, False, False, False, False]
+        own_sock = f"/run/user/{os.getuid()}/docker.sock"
+        alt_sock = "/run/user/999/docker.sock"
+        with (
+            patch("devx.molecule.start_docker.glob.glob", return_value=[own_sock, alt_sock]),
+            patch("devx.molecule.start_docker.time.sleep"),
+            patch("devx.molecule.start_docker.subprocess.Popen"),
+            patch("devx.molecule.start_docker.tempfile.NamedTemporaryFile") as mock_ntf,
+            patch("builtins.open", mock_open(read_data="err")),
+        ):
+            mock_ntf.return_value = MagicMock(name="/tmp/dockerd.log")
+            assert start_docker_daemon(timeout=2) is False
+
+    @patch("devx.molecule.start_docker.glob.glob", return_value=[])
+    @patch("devx.molecule.start_docker._diagnose_socket")
+    @patch("devx.molecule.start_docker.os.path.exists", return_value=False)
+    @patch("devx.molecule.start_docker.is_docker_ready", return_value=False)
+    @patch("devx.molecule.start_docker.time.sleep")
+    @patch("devx.molecule.start_docker.subprocess.Popen")
+    @patch("devx.molecule.start_docker.tempfile.NamedTemporaryFile")
+    def test_starts_local_daemon(
+        self,
+        mock_ntf: MagicMock,
+        mock_popen: MagicMock,
+        mock_sleep: MagicMock,
+        mock_ready: MagicMock,
+        mock_exists: MagicMock,
+        mock_diag: MagicMock,
+        mock_glob: MagicMock,
+    ) -> None:
+        mock_ntf.return_value = MagicMock(name="/tmp/dockerd.log")
+        # Host fails, rootless doesn't exist, local daemon starts
+        mock_ready.side_effect = [False, False, False, False, True]
         assert start_docker_daemon(timeout=5) is True
         mock_popen.assert_called_once()
-        mock_sleep.assert_called_once_with(1)
+        popen_args = mock_popen.call_args.args[0]
+        assert "dockerd" in popen_args
+        assert "--storage-driver" in popen_args
+        assert "vfs" in popen_args
+        assert "-H" in popen_args
 
-    @patch("devx.molecule.start_docker.time.sleep")
+    @patch("devx.molecule.start_docker.glob.glob", return_value=[])
+    @patch("devx.molecule.start_docker._diagnose_socket")
+    @patch("devx.molecule.start_docker.os.path.exists", return_value=False)
     @patch("devx.molecule.start_docker.is_docker_ready", return_value=False)
+    @patch("devx.molecule.start_docker.time.sleep")
     @patch("devx.molecule.start_docker.subprocess.Popen")
-    @patch("builtins.open", new_callable=mock_open)
+    @patch("devx.molecule.start_docker.tempfile.NamedTemporaryFile")
     def test_fails_after_timeout(
         self,
-        mock_file: MagicMock,
+        mock_ntf: MagicMock,
         mock_popen: MagicMock,
-        mock_ready: MagicMock,
         mock_sleep: MagicMock,
+        mock_ready: MagicMock,
+        mock_exists: MagicMock,
+        mock_diag: MagicMock,
+        mock_glob: MagicMock,
     ) -> None:
-        assert start_docker_daemon(timeout=3) is False
+        mock_ntf.return_value = MagicMock(name="/tmp/dockerd.log")
+        with patch("builtins.open", mock_open(read_data="dockerd error log")):
+            assert start_docker_daemon(timeout=3) is False
         mock_popen.assert_called_once()
         assert mock_sleep.call_count == 3
 
+    @patch("devx.molecule.start_docker.glob.glob", return_value=[])
+    @patch("devx.molecule.start_docker._diagnose_socket")
+    @patch("devx.molecule.start_docker.os.path.exists", return_value=False)
+    @patch("devx.molecule.start_docker.is_docker_ready", return_value=False)
     @patch("devx.molecule.start_docker.time.sleep")
-    @patch("devx.molecule.start_docker.is_docker_ready")
     @patch("devx.molecule.start_docker.subprocess.Popen")
-    @patch("builtins.open", new_callable=mock_open)
-    def test_ready_on_first_check(
+    @patch("devx.molecule.start_docker.tempfile.NamedTemporaryFile")
+    def test_fails_log_read_error(
         self,
-        mock_file: MagicMock,
+        mock_ntf: MagicMock,
         mock_popen: MagicMock,
-        mock_ready: MagicMock,
         mock_sleep: MagicMock,
+        mock_ready: MagicMock,
+        mock_exists: MagicMock,
+        mock_diag: MagicMock,
+        mock_glob: MagicMock,
     ) -> None:
-        mock_ready.return_value = True
-        assert start_docker_daemon(timeout=5) is True
-        mock_popen.assert_called_once()
-        mock_sleep.assert_not_called()
+        """Should handle log read errors gracefully."""
+        mock_ntf.return_value = MagicMock(name="/tmp/dockerd.log")
+        with patch("builtins.open", side_effect=OSError("permission denied")):
+            assert start_docker_daemon(timeout=2) is False
 
-    @patch("devx.molecule.start_docker.time.sleep")
+    @patch("devx.molecule.start_docker.glob.glob", return_value=[])
+    @patch("devx.molecule.start_docker._diagnose_socket")
+    @patch("devx.molecule.start_docker.os.path.exists", return_value=False)
     @patch("devx.molecule.start_docker.is_docker_ready")
+    @patch("devx.molecule.start_docker.time.sleep")
     @patch("devx.molecule.start_docker.subprocess.Popen")
-    @patch("builtins.open", new_callable=mock_open)
-    def test_custom_timeout(
+    @patch("devx.molecule.start_docker.tempfile.NamedTemporaryFile")
+    def test_local_daemon_ready_on_first_check(
         self,
-        mock_file: MagicMock,
+        mock_ntf: MagicMock,
         mock_popen: MagicMock,
-        mock_ready: MagicMock,
         mock_sleep: MagicMock,
+        mock_ready: MagicMock,
+        mock_exists: MagicMock,
+        mock_diag: MagicMock,
+        mock_glob: MagicMock,
     ) -> None:
-        # 9 iterations not ready, 10th ready.
-        mock_ready.side_effect = [False] * 9 + [True]
-        assert start_docker_daemon(timeout=10) is True
-        assert mock_sleep.call_count == 9
+        mock_ntf.return_value = MagicMock(name="/tmp/dockerd.log")
+        # Host fails, rootless doesn't exist, local ready on first loop check
+        mock_ready.side_effect = [False, False, True]
+        assert start_docker_daemon(timeout=5) is True
+        assert mock_popen.call_count == 1
+        assert mock_sleep.call_count == 1
+
+    @patch("devx.molecule.start_docker._diagnose_socket")
+    @patch("devx.molecule.start_docker.os.environ")
+    @patch("devx.molecule.start_docker.is_docker_ready", return_value=True)
+    def test_sets_docker_host(
+        self,
+        mock_ready: MagicMock,
+        mock_environ: MagicMock,
+        mock_diag: MagicMock,
+    ) -> None:
+        """DOCKER_HOST must be set so molecule connects to correct socket."""
+        start_docker_daemon(timeout=5)
+        mock_environ.__setitem__.assert_called_with("DOCKER_HOST", f"unix://{DOCKER_SOCK}")
 
 
 class TestMain:
@@ -105,3 +255,24 @@ class TestMain:
         result = runner.invoke(main, ["--timeout", "60"])
         assert result.exit_code == 0
         mock_start.assert_called_once_with(60)
+
+    @patch("devx.molecule.start_docker.os.environ.get")
+    @patch("devx.molecule.start_docker.start_docker_daemon", return_value=True)
+    def test_exports_github_env(self, mock_start: MagicMock, mock_get: MagicMock) -> None:
+        """Should write DOCKER_HOST to GITHUB_ENV when available."""
+        mock_get.side_effect = lambda key, default="": (
+            "/tmp/github_env" if key == "GITHUB_ENV" else f"unix://{DOCKER_SOCK}" if key == "DOCKER_HOST" else default
+        )
+        with patch("builtins.open", mock_open()) as mock_file:
+            runner = CliRunner()
+            result = runner.invoke(main, [])
+            assert result.exit_code == 0
+            mock_file.assert_called_with("/tmp/github_env", "a")
+
+    @patch("devx.molecule.start_docker.os.environ.get", return_value="")
+    @patch("devx.molecule.start_docker.start_docker_daemon", return_value=True)
+    def test_no_github_env(self, mock_start: MagicMock, mock_get: MagicMock) -> None:
+        """Should not crash when GITHUB_ENV is not set."""
+        runner = CliRunner()
+        result = runner.invoke(main, [])
+        assert result.exit_code == 0