fix(web): stop reporting "no update" when the update check could not run

test/test_update_check_reports_failure.py

@@ -0,0 +1,85 @@
+"""A check that could not run must not be reported as "up to date".
+
+check-update returned update_available=False whenever git failed. The banner
+is the only route to the update button, so a checkout git refuses to touch
+looked exactly like a current one -- permanently, and with nothing for the
+user to act on. The usual cause is an install performed as root, after which
+every git command fails with "detected dubious ownership".
+"""
+import subprocess
+import sys
+from pathlib import Path
+from unittest.mock import patch
+
+import pytest
+from flask import Flask
+
+sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
+
+from web_interface.blueprints import api_v3 as mod  # noqa: E402
+from web_interface.blueprints.api_v3 import api_v3  # noqa: E402
+
+DUBIOUS = ("fatal: detected dubious ownership in repository at "
+           "'/home/pi/LEDMatrix'\nTo add an exception for this directory, call:\n"
+           "\tgit config --global --add safe.directory /home/pi/LEDMatrix\n")
+
+
+@pytest.fixture
+def client():
+    app = Flask(__name__)
+    app.config['TESTING'] = True
+    app.register_blueprint(api_v3, url_prefix='/api/v3')
+    mod._update_check_cache['result'] = None
+    mod._update_check_cache['ts'] = 0
+    return app.test_client()
+
+
+def _fetch_fails(stderr: bytes):
+    def fake_run(args, **kwargs):
+        if args[:2] == ['git', 'fetch']:
+            return subprocess.CompletedProcess(args, 1, stdout=b'', stderr=stderr)
+        return subprocess.CompletedProcess(args, 0, stdout='', stderr='')
+    return fake_run
+
+
+class TestFailedCheckIsNotSilence:
+    def test_dubious_ownership_is_reported_not_swallowed(self, client):
+        with patch.object(mod.subprocess, 'run', _fetch_fails(DUBIOUS.encode())):
+            data = client.get('/api/v3/system/check-update').get_json()
+        assert data['check_failed'] is True, (
+            "a git failure was reported as a successful 'no update' check")
+        assert data['update_available'] is False
+
+    def test_the_message_tells_the_user_what_to_do(self, client):
+        with patch.object(mod.subprocess, 'run', _fetch_fails(DUBIOUS.encode())):
+            data = client.get('/api/v3/system/check-update').get_json()
+        assert 'chown' in data['error'], (
+            "dubious ownership is unactionable without the fix command")
+        assert 'root' in data['error']
+
+    def test_an_ordinary_git_failure_still_surfaces(self, client):
+        with patch.object(mod.subprocess, 'run',
+                          _fetch_fails(b'fatal: some other git problem\n')):
+            data = client.get('/api/v3/system/check-update').get_json()
+        assert data['check_failed'] is True
+        assert 'some other git problem' in data['error']
+
+    def test_offline_reads_as_offline(self, client):
+        with patch.object(mod.subprocess, 'run',
+                          _fetch_fails(b'fatal: could not resolve host: github.com\n')):
+            data = client.get('/api/v3/system/check-update').get_json()
+        assert 'Could not reach GitHub' in data['error']
+
+
+class TestSuccessPathUnchanged:
+    def test_up_to_date_carries_no_failure_flag(self, client):
+        def fake_run(args, **kwargs):
+            if args[:2] == ['git', 'fetch']:
+                return subprocess.CompletedProcess(args, 0, stdout=b'', stderr=b'')
+            if args[:2] == ['git', 'rev-parse']:
+                return subprocess.CompletedProcess(args, 0, stdout='abc123\n', stderr='')
+            return subprocess.CompletedProcess(args, 0, stdout='0\n', stderr='')
+        with patch.object(mod.subprocess, 'run', fake_run):
+            data = client.get('/api/v3/system/check-update').get_json()
+        assert data['update_available'] is False
+        assert not data.get('check_failed'), "a healthy check must not look like a failure"

web_interface/blueprints/api_v3.py

@@ -1821,6 +1821,33 @@ def get_system_version():
 _update_check_cache: Dict[str, Any] = {'result': None, 'ts': 0.0}
 _UPDATE_CHECK_TTL = 300  # 5 minutes — avoids a git fetch on every page load
 
+def _update_check_failed(detail: str) -> Dict[str, Any]:
+    """A check that could not run is not the same as being up to date.
+
+    Reporting update_available=False on a git failure hides the banner, and
+    the banner is the only route to the update button -- so a checkout git
+    refuses to touch looks exactly like a current one, permanently. The most
+    common cause is an install performed as root: git then reports "dubious
+    ownership" and every command fails, including the fetch here.
+    """
+    return {'update_available': False, 'remote_sha': 'unknown',
+            'commits_behind': 0, 'check_failed': True, 'error': detail}
+
+
+def _describe_git_failure(stderr: str) -> str:
+    """Turn git's stderr into something the user can act on."""
+    text = (stderr or '').strip()
+    if 'dubious ownership' in text or 'detected dubious ownership' in text:
+        return ("This checkout is owned by a different user than the one "
+                "running the web interface, so git refuses to use it. It is "
+                "usually the result of installing as root. Fix the ownership "
+                "and the update will work: sudo chown -R $USER:$USER "
+                + str(PROJECT_ROOT))
+    if 'could not resolve host' in text.lower() or 'network is unreachable' in text.lower():
+        return "Could not reach GitHub to check for updates."
+    return "Could not check for updates: " + (text.splitlines()[0] if text else "git failed")
+
+
 @api_v3.route('/system/check-update', methods=['GET'])
 def check_for_update():
     """Check whether a newer LEDMatrix commit is available on origin/main."""
@@ -1836,12 +1863,13 @@ def check_for_update():
             capture_output=True, timeout=10, cwd=cwd,
         )
         if fetch_result.returncode != 0:
+            stderr = fetch_result.stderr.decode(errors='replace').strip()
             logger.warning("check-update: git fetch failed (rc=%d): %s",
-                           fetch_result.returncode,
-                           fetch_result.stderr.decode(errors='replace').strip())
-            _update_check_cache['result'] = _safe
+                           fetch_result.returncode, stderr)
+            failed = _update_check_failed(_describe_git_failure(stderr))
+            _update_check_cache['result'] = failed
             _update_check_cache['ts'] = now
-            return jsonify(_safe)
+            return jsonify(failed)
         local = subprocess.run(
             ['git', 'rev-parse', 'HEAD'],
             capture_output=True, text=True, timeout=5, cwd=cwd,
@@ -1869,7 +1897,8 @@ def check_for_update():
         return jsonify(result)
     except Exception as e:
         logger.warning("check-update failed: %s", e)
-        return jsonify(_safe)
+        return jsonify(_update_check_failed(
+            "Could not check for updates; see logs for details."))
 
 @api_v3.route('/system/action', methods=['POST'])
 def execute_system_action():

web_interface/templates/v3/base.html

@@ -1107,15 +1107,29 @@ <h3 id="on-demand-modal-title" class="text-lg font-semibold">Run Plugin On-Deman
         fetch('/api/v3/system/check-update')
             .then(function(r) { return r.json(); })
             .then(function(data) {
+                var banner = document.getElementById('update-banner');
+                var btn = document.getElementById('update-banner-btn');
+                if (data.check_failed) {
+                    // A check that could not run is not the same as being up
+                    // to date. Hiding the banner here made a checkout git
+                    // refuses to touch look permanently current, with no
+                    // route to the update button and nothing to act on.
+                    document.getElementById('update-banner-text').textContent =
+                        data.error || 'Could not check for updates.';
+                    if (btn) btn.style.display = 'none';
+                    banner.style.display = '';
+                    return;
+                }
+                if (btn) btn.style.display = '';
                 if (data.update_available && getDismissedSha() !== data.remote_sha) {
                     var n = data.commits_behind || 0;
                     var msg = 'A new LEDMatrix update is available';
                     if (n > 0) msg += ' (' + n + ' commit' + (n > 1 ? 's' : '') + ')';
                     document.getElementById('update-banner-text').textContent = msg;
-                    document.getElementById('update-banner').style.display = '';
+                    banner.style.display = '';
                     try { sessionStorage.setItem('update-sha', data.remote_sha); } catch(e) {}
                 } else {
-                    document.getElementById('update-banner').style.display = 'none';
+                    banner.style.display = 'none';
                 }
             })
             .catch(function() {});