From fc35a5b632299702ba4faac3891d5aa33a889af6 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Mon, 24 Aug 2026 08:25:35 +0000
Subject: [PATCH 1/8] Render qcodes timestamps in local timezone; handle new %z
 format

Co-authored-by: astafan8 <15662810+astafan8@users.noreply.github.com>
---
 plottr/data/qcodes_dataset.py   | 18 ++++++++++++++----
 test/pytest/test_qcodes_data.py | 21 +++++++++++++--------
 2 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/plottr/data/qcodes_dataset.py b/plottr/data/qcodes_dataset.py
index 551aa160..7d57c632 100644
--- a/plottr/data/qcodes_dataset.py
+++ b/plottr/data/qcodes_dataset.py
@@ -47,19 +47,29 @@ def _get_names_of_standalone_parameters(paramspecs: List['ParamSpec']
 def _split_timestamp(ts: Optional[str]) -> Tuple[str, str]:
     """Split a qcodes timestamp string into (date, time) components.
 
-    Uses datetime parsing instead of string slicing for robustness.
+    Uses datetime parsing instead of string slicing for robustness. This
+    handles both the legacy qcodes timestamp format (``"YYYY-MM-DD HH:MM:SS"``)
+    and the newer one that includes the UTC offset of the local timezone
+    (``"YYYY-MM-DD HH:MM:SS%z"``, e.g. ``"2026-07-31 10:27:25+0200"``).
 
-    :param ts: timestamp string as returned by ``ds.run_timestamp()``
-        (typically ``"YYYY-MM-DD HH:MM:SS"``), or None.
+    Timezone-aware timestamps are converted to the local timezone of the
+    machine running plottr before formatting, so the rendered date and time
+    always reflect the local (PC) timezone. The UTC offset itself is dropped
+    from the returned components.
+
+    :param ts: timestamp string as returned by ``ds.run_timestamp()``, or None.
     :returns: (date_str, time_str) or ('', '') if ts is None or unparsable.
     """
     if ts is None:
         return '', ''
     try:
         dt = datetime.fromisoformat(ts)
-        return dt.strftime('%Y-%m-%d'), dt.strftime('%H:%M:%S')
     except (ValueError, TypeError):
         return '', ''
+    if dt.tzinfo is not None:
+        # Render in the local timezone of the machine running plottr.
+        dt = dt.astimezone()
+    return dt.strftime('%Y-%m-%d'), dt.strftime('%H:%M:%S')
 
 
 class IndependentParameterDict(TypedDict):
diff --git a/test/pytest/test_qcodes_data.py b/test/pytest/test_qcodes_data.py
index a188c0b6..c75348c9 100644
--- a/test/pytest/test_qcodes_data.py
+++ b/test/pytest/test_qcodes_data.py
@@ -13,7 +13,8 @@
     get_ds_structure,
     get_ds_info,
     get_runs_from_db,
-    ds_to_datadict)
+    ds_to_datadict,
+    _split_timestamp)
 
 
 @pytest.fixture(scope='function')
@@ -201,17 +202,21 @@ def test_get_ds_info(experiment):
 
     # timestamps are difficult to test for, so we will cheat here and
     # instead of hard-coding timestamps we will just get them from the dataset
-    # The same applies to the guid as it contains the timestamp
-    started_ts = dataset.run_timestamp()
-    completed_ts = dataset.completed_timestamp()
+    # The same applies to the guid as it contains the timestamp.
+    # We parse the qcodes timestamps the same way ``get_ds_info`` does, so that
+    # this test is robust to the qcodes timestamp format (in particular the
+    # newer format that appends the local UTC offset, e.g.
+    # "2026-07-31 10:27:25+0200").
+    started_date, started_time = _split_timestamp(dataset.run_timestamp())
+    completed_date, completed_time = _split_timestamp(dataset.completed_timestamp())
 
     expected_ds_info = {
         'experiment': '2d_softsweep',
         'sample': 'no sample',
-        'completed_date': completed_ts[:10],
-        'completed_time': completed_ts[11:],
-        'started_date': started_ts[:10],
-        'started_time': started_ts[11:],
+        'completed_date': completed_date,
+        'completed_time': completed_time,
+        'started_date': started_date,
+        'started_time': started_time,
         'name': 'results',
         'structure': None,
         'records': 0,

From 079dfb04ae7671f9c77641fd000c97fd0bb4b7e5 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Mon, 24 Aug 2026 08:26:17 +0000
Subject: [PATCH 2/8] Guard timestamp formatting/conversion with consistent
 error handling

Co-authored-by: astafan8 <15662810+astafan8@users.noreply.github.com>
---
 plottr/data/qcodes_dataset.py | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/plottr/data/qcodes_dataset.py b/plottr/data/qcodes_dataset.py
index 7d57c632..b05a0ae3 100644
--- a/plottr/data/qcodes_dataset.py
+++ b/plottr/data/qcodes_dataset.py
@@ -64,12 +64,12 @@ def _split_timestamp(ts: Optional[str]) -> Tuple[str, str]:
         return '', ''
     try:
         dt = datetime.fromisoformat(ts)
-    except (ValueError, TypeError):
+        if dt.tzinfo is not None:
+            # Render in the local timezone of the machine running plottr.
+            dt = dt.astimezone()
+        return dt.strftime('%Y-%m-%d'), dt.strftime('%H:%M:%S')
+    except (ValueError, TypeError, OSError, OverflowError):
         return '', ''
-    if dt.tzinfo is not None:
-        # Render in the local timezone of the machine running plottr.
-        dt = dt.astimezone()
-    return dt.strftime('%Y-%m-%d'), dt.strftime('%H:%M:%S')
 
 
 class IndependentParameterDict(TypedDict):

From 94c97027f562359fa2be0f3b18f14f5244367e91 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Tue, 25 Aug 2026 06:12:13 +0000
Subject: [PATCH 3/8] Fix mypy CI crash on qcodes; test _split_timestamp
 independently

Co-authored-by: astafan8 <15662810+astafan8@users.noreply.github.com>
---
 pyproject.toml                  | 11 +++++++
 test/pytest/test_qcodes_data.py | 54 +++++++++++++++++++++++++++------
 2 files changed, 55 insertions(+), 10 deletions(-)

diff --git a/pyproject.toml b/pyproject.toml
index 9c8124b7..980ec61b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -117,6 +117,17 @@ module = [
 ]
 ignore_missing_imports = true
 
+# qcodes ships a py.typed marker, so mypy type-checks its source when following
+# imports from plottr. mypy 2.3.1 crashes with an INTERNAL ERROR while analysing
+# ``qcodes.dataset.data_set_protocol``. Skip following imports into qcodes so we
+# do not type-check a third-party library (and work around the mypy crash).
+[[tool.mypy.overrides]]
+module = [
+    "qcodes.*",
+]
+follow_imports = "skip"
+follow_imports_for_stubs = true
+
 [tool.versioningit]
 default-version = "0.0"
 
diff --git a/test/pytest/test_qcodes_data.py b/test/pytest/test_qcodes_data.py
index c75348c9..10930f0a 100644
--- a/test/pytest/test_qcodes_data.py
+++ b/test/pytest/test_qcodes_data.py
@@ -1,3 +1,5 @@
+import datetime
+
 import numpy as np
 import pytest
 from packaging import version
@@ -181,6 +183,39 @@ def test_get_ds_structure(experiment):
     assert structure == expected_structure
 
 
+def test_split_timestamp_naive():
+    # The legacy qcodes timestamp format has no timezone information and is
+    # returned as-is (split into date and time). Expected values are hard-coded
+    # so this does not depend on the helper's own logic.
+    assert _split_timestamp("2026-07-31 10:27:25") == ("2026-07-31", "10:27:25")
+
+
+def test_split_timestamp_none_and_invalid():
+    assert _split_timestamp(None) == ("", "")
+    assert _split_timestamp("") == ("", "")
+    assert _split_timestamp("not a timestamp") == ("", "")
+
+
+def test_split_timestamp_timezone_aware_rendered_in_local_time():
+    # The new qcodes timestamp format includes the UTC offset. Such timestamps
+    # must be converted to the local timezone of the machine before being split.
+    # We compute the expected local date/time independently from the helper:
+    # take a fixed absolute instant, convert it to local wall-clock time via
+    # ``datetime.fromtimestamp`` (a different code path than the helper), and
+    # verify the helper agrees for the same instant given in different offsets.
+    utc_instant = datetime.datetime(2026, 7, 31, 8, 27, 25,
+                                    tzinfo=datetime.timezone.utc)
+    local = datetime.datetime.fromtimestamp(utc_instant.timestamp())
+    expected = (local.strftime("%Y-%m-%d"), local.strftime("%H:%M:%S"))
+
+    # Same instant expressed as UTC (+00:00) and as +02:00.
+    assert _split_timestamp("2026-07-31 08:27:25+00:00") == expected
+    assert _split_timestamp("2026-07-31 10:27:25+02:00") == expected
+    # qcodes renders the offset without a colon (e.g. "+0000"); ensure that
+    # format is handled too.
+    assert _split_timestamp("2026-07-31 08:27:25+0000") == expected
+
+
 def test_get_ds_info(experiment):
     N = 5
 
@@ -203,20 +238,19 @@ def test_get_ds_info(experiment):
     # timestamps are difficult to test for, so we will cheat here and
     # instead of hard-coding timestamps we will just get them from the dataset
     # The same applies to the guid as it contains the timestamp.
-    # We parse the qcodes timestamps the same way ``get_ds_info`` does, so that
-    # this test is robust to the qcodes timestamp format (in particular the
-    # newer format that appends the local UTC offset, e.g.
-    # "2026-07-31 10:27:25+0200").
-    started_date, started_time = _split_timestamp(dataset.run_timestamp())
-    completed_date, completed_time = _split_timestamp(dataset.completed_timestamp())
+    # To avoid testing ``get_ds_info`` against the very helper it uses
+    # (``_split_timestamp``), we derive the expected local date/time
+    # independently from the raw unix timestamps exposed by qcodes.
+    started = datetime.datetime.fromtimestamp(dataset.run_timestamp_raw)
+    completed = datetime.datetime.fromtimestamp(dataset.completed_timestamp_raw)
 
     expected_ds_info = {
         'experiment': '2d_softsweep',
         'sample': 'no sample',
-        'completed_date': completed_date,
-        'completed_time': completed_time,
-        'started_date': started_date,
-        'started_time': started_time,
+        'completed_date': completed.strftime('%Y-%m-%d'),
+        'completed_time': completed.strftime('%H:%M:%S'),
+        'started_date': started.strftime('%Y-%m-%d'),
+        'started_time': started.strftime('%H:%M:%S'),
         'name': 'results',
         'structure': None,
         'records': 0,

From ba9ab3df890da5fef521cd9c485746b5a353e081 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Tue, 25 Aug 2026 10:08:44 +0000
Subject: [PATCH 4/8] Add date-boundary test case for _split_timestamp

Co-authored-by: astafan8 <15662810+astafan8@users.noreply.github.com>
---
 test/pytest/test_qcodes_data.py | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/test/pytest/test_qcodes_data.py b/test/pytest/test_qcodes_data.py
index 10930f0a..3ffaec6e 100644
--- a/test/pytest/test_qcodes_data.py
+++ b/test/pytest/test_qcodes_data.py
@@ -216,6 +216,20 @@ def test_split_timestamp_timezone_aware_rendered_in_local_time():
     assert _split_timestamp("2026-07-31 08:27:25+0000") == expected
 
 
+def test_split_timestamp_timezone_aware_crosses_date_boundary():
+    # Converting to local time can push the timestamp onto a different
+    # calendar date than the one written in the input string. Expected
+    # values are again derived independently via ``datetime.fromtimestamp``.
+    utc_instant = datetime.datetime(2026, 7, 31, 23, 30, 0,
+                                    tzinfo=datetime.timezone.utc)
+    local = datetime.datetime.fromtimestamp(utc_instant.timestamp())
+    expected = (local.strftime("%Y-%m-%d"), local.strftime("%H:%M:%S"))
+
+    # Same instant, expressed with a +02:00 offset, which shifts the
+    # calendar date in the input string to the next day.
+    assert _split_timestamp("2026-08-01 01:30:00+02:00") == expected
+
+
 def test_get_ds_info(experiment):
     N = 5
 

From f66ae69eb03d41a87b49c5f52f0a3289b19f61ac Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Tue, 25 Aug 2026 10:09:54 +0000
Subject: [PATCH 5/8] Pin local timezone in date-boundary test for determinism

Co-authored-by: astafan8 <15662810+astafan8@users.noreply.github.com>
---
 test/pytest/test_qcodes_data.py | 33 ++++++++++++++++++++++-----------
 1 file changed, 22 insertions(+), 11 deletions(-)

diff --git a/test/pytest/test_qcodes_data.py b/test/pytest/test_qcodes_data.py
index 3ffaec6e..d66c3654 100644
--- a/test/pytest/test_qcodes_data.py
+++ b/test/pytest/test_qcodes_data.py
@@ -1,4 +1,5 @@
 import datetime
+import time
 
 import numpy as np
 import pytest
@@ -216,18 +217,28 @@ def test_split_timestamp_timezone_aware_rendered_in_local_time():
     assert _split_timestamp("2026-07-31 08:27:25+0000") == expected
 
 
-def test_split_timestamp_timezone_aware_crosses_date_boundary():
+def test_split_timestamp_timezone_aware_crosses_date_boundary(monkeypatch):
     # Converting to local time can push the timestamp onto a different
-    # calendar date than the one written in the input string. Expected
-    # values are again derived independently via ``datetime.fromtimestamp``.
-    utc_instant = datetime.datetime(2026, 7, 31, 23, 30, 0,
-                                    tzinfo=datetime.timezone.utc)
-    local = datetime.datetime.fromtimestamp(utc_instant.timestamp())
-    expected = (local.strftime("%Y-%m-%d"), local.strftime("%H:%M:%S"))
-
-    # Same instant, expressed with a +02:00 offset, which shifts the
-    # calendar date in the input string to the next day.
-    assert _split_timestamp("2026-08-01 01:30:00+02:00") == expected
+    # calendar date than the one written in the input string. The local
+    # timezone is pinned explicitly so the boundary crossing is guaranteed
+    # regardless of the host machine's own timezone. Expected values are
+    # again derived independently via ``datetime.fromtimestamp``.
+    if not hasattr(time, "tzset"):
+        pytest.skip("time.tzset is not available on this platform")
+
+    monkeypatch.setenv("TZ", "Europe/Berlin")
+    time.tzset()
+    try:
+        utc_instant = datetime.datetime(2026, 7, 31, 23, 30, 0,
+                                        tzinfo=datetime.timezone.utc)
+        local = datetime.datetime.fromtimestamp(utc_instant.timestamp())
+        expected = (local.strftime("%Y-%m-%d"), local.strftime("%H:%M:%S"))
+
+        # Same instant, expressed with a +02:00 offset, which shifts the
+        # calendar date in the input string to the next day.
+        assert _split_timestamp("2026-08-01 01:30:00+02:00") == expected
+    finally:
+        time.tzset()
 
 
 def test_get_ds_info(experiment):

From 75e31987b45c030190ec5b1a907bee003ed00f01 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Tue, 25 Aug 2026 12:03:45 +0000
Subject: [PATCH 6/8] Restore qcodes mypy type-checking; downgrade mypy to
 working version

Co-authored-by: astafan8 <15662810+astafan8@users.noreply.github.com>
---
 pyproject.toml        | 11 -----------
 test_requirements.txt |  2 +-
 2 files changed, 1 insertion(+), 12 deletions(-)

diff --git a/pyproject.toml b/pyproject.toml
index 980ec61b..9c8124b7 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -117,17 +117,6 @@ module = [
 ]
 ignore_missing_imports = true
 
-# qcodes ships a py.typed marker, so mypy type-checks its source when following
-# imports from plottr. mypy 2.3.1 crashes with an INTERNAL ERROR while analysing
-# ``qcodes.dataset.data_set_protocol``. Skip following imports into qcodes so we
-# do not type-check a third-party library (and work around the mypy crash).
-[[tool.mypy.overrides]]
-module = [
-    "qcodes.*",
-]
-follow_imports = "skip"
-follow_imports_for_stubs = true
-
 [tool.versioningit]
 default-version = "0.0"
 
diff --git a/test_requirements.txt b/test_requirements.txt
index 4b58a050..fd992016 100644
--- a/test_requirements.txt
+++ b/test_requirements.txt
@@ -2,7 +2,7 @@ qcodes
 pytest
 pytest-qt
 hypothesis
-mypy==2.3.1
+mypy==2.1.0
 PySide6-stubs
 pandas-stubs
 watchdog
\ No newline at end of file

From c65e066e17ae58e10560bf5dc07346c7fe9f5fc2 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Tue, 25 Aug 2026 12:06:57 +0000
Subject: [PATCH 7/8] Document why mypy is pinned to 2.1.0 in
 test_requirements.txt

Co-authored-by: astafan8 <15662810+astafan8@users.noreply.github.com>
---
 test_requirements.txt | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/test_requirements.txt b/test_requirements.txt
index fd992016..9c9eb11a 100644
--- a/test_requirements.txt
+++ b/test_requirements.txt
@@ -2,6 +2,10 @@ qcodes
 pytest
 pytest-qt
 hypothesis
+# mypy >=2.2.0 crashes with an INTERNAL ERROR while following imports into
+# qcodes' data_set_protocol.py (verified up to 2.3.1, the latest release as
+# of writing). Pinned to 2.1.0, the newest version that doesn't crash; bump
+# once upstream fixes this (see https://github.com/python/mypy/issues).
 mypy==2.1.0
 PySide6-stubs
 pandas-stubs

From 879f568921b8ce3e945667a1b27fac2276a9eb00 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Tue, 25 Aug 2026 14:07:05 +0000
Subject: [PATCH 8/8] Link upstream mypy issue #21741 in test_requirements.txt
 comment

Co-authored-by: astafan8 <15662810+astafan8@users.noreply.github.com>
---
 test_requirements.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test_requirements.txt b/test_requirements.txt
index 9c9eb11a..0a59f9e4 100644
--- a/test_requirements.txt
+++ b/test_requirements.txt
@@ -5,7 +5,7 @@ hypothesis
 # mypy >=2.2.0 crashes with an INTERNAL ERROR while following imports into
 # qcodes' data_set_protocol.py (verified up to 2.3.1, the latest release as
 # of writing). Pinned to 2.1.0, the newest version that doesn't crash; bump
-# once upstream fixes this (see https://github.com/python/mypy/issues).
+# once upstream fixes this (see https://github.com/python/mypy/issues/21741).
 mypy==2.1.0
 PySide6-stubs
 pandas-stubs