From 075bfa56ecbf6fd219aa82f327e863a74b764524 Mon Sep 17 00:00:00 2001
From: Dongdong Tian <seisman.info@gmail.com>
Date: Thu, 19 Jun 2025 12:35:23 +0800
Subject: [PATCH 1/2] Fix the bug that passing a sequence that contains True to
 a parameter

---
 pygmt/helpers/utils.py | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/pygmt/helpers/utils.py b/pygmt/helpers/utils.py
index 387d61e03b3..dac58eb160c 100644
--- a/pygmt/helpers/utils.py
+++ b/pygmt/helpers/utils.py
@@ -524,6 +524,8 @@ def build_arg_list(  # noqa: PLR0912
     ['-A1/2/3/4', '-BWSen', '-Bxaf', '-Byaf', '-C1p', '-C2p']
     >>> build_arg_list(dict(B=["af", "WSne+tBlank Space"]))
     ['-BWSne+tBlank Space', '-Baf']
+    >>> build_arg_list(dict(B=[True, "+tTitle"]))
+    ['-B', '-B+tTitle']
     >>> build_arg_list(dict(F='+t"Empty Spaces"'))
     ['-F+t"Empty Spaces"']
     >>> build_arg_list(dict(l="'Void Space'"))
@@ -565,7 +567,10 @@ def build_arg_list(  # noqa: PLR0912
         elif value is True:
             gmt_args.append(f"-{key}")
         elif is_nonstr_iter(value):
-            gmt_args.extend(f"-{key}{_value}" for _value in value)
+            gmt_args.extend(
+                f"-{key}{_value}" if _value is not True else f"-{key}"
+                for _value in value
+            )
         else:
             gmt_args.append(f"-{key}{value}")
 

From 919782bf6711080d44a5e835ed2bd7e4e5f2c4ea Mon Sep 17 00:00:00 2001
From: Dongdong Tian <seisman.info@gmail.com>
Date: Mon, 23 Jun 2025 17:12:56 +0800
Subject: [PATCH 2/2] Add one test

---
 .../test_basemap_frame_sequence_true.png.dvc         |  5 +++++
 pygmt/tests/test_basemap.py                          | 12 ++++++++++++
 2 files changed, 17 insertions(+)
 create mode 100644 pygmt/tests/baseline/test_basemap_frame_sequence_true.png.dvc

diff --git a/pygmt/tests/baseline/test_basemap_frame_sequence_true.png.dvc b/pygmt/tests/baseline/test_basemap_frame_sequence_true.png.dvc
new file mode 100644
index 00000000000..ed3a6aaf199
--- /dev/null
+++ b/pygmt/tests/baseline/test_basemap_frame_sequence_true.png.dvc
@@ -0,0 +1,5 @@
+outs:
+- md5: b04af7fe4c42e405adb600cc3d6d3272
+  size: 11679
+  hash: md5
+  path: test_basemap_frame_sequence_true.png
diff --git a/pygmt/tests/test_basemap.py b/pygmt/tests/test_basemap.py
index c75459c99ca..a88f015b0e9 100644
--- a/pygmt/tests/test_basemap.py
+++ b/pygmt/tests/test_basemap.py
@@ -143,3 +143,15 @@ def test_basemap_subplot():
         with fig.set_panel(panel=1):
             fig.basemap(region=[0, 10, 0, 10], projection="X?")
     return fig
+
+
+@pytest.mark.mpl_image_compare
+def test_basemap_frame_sequence_true():
+    """
+    Test that passing a sequence with True works.
+
+    Test for https://github.com/GenericMappingTools/pygmt/issues/3981.
+    """
+    fig = Figure()
+    fig.basemap(region=[0, 10, 0, 10], projection="X10c", frame=[True, "WSen"])
+    return fig