Fix issue with rerunning tasks via pytask.build.

docs/source/changes.md

@@ -13,6 +13,8 @@ releases are available on [PyPI](https://pypi.org/project/pytask) and
 - {pull}`619` makes coiled an optional import for tests. Thanks to {user}`erooke`.
 - {pull}`620` makes tests more flexible about their location. Thanks to {user}`erooke`.
 - {pull}`621` fixes the pull requests template.
+- {pull}`626` resolves an issue with rerunning tasks via the programmatic API. Closes
+  {issue}`625`. Thanks to @noppelmax for the issue!
 - {pull}`627` adds a warning when users explicitly pass files to pytask that pytask is
   going to ignore because they do not match a pattern. Happens quite often when the task
   module's name does not start with `task_`.

src/_pytask/collect.py

@@ -7,6 +7,7 @@
 import os
 import sys
 import time
+from contextlib import suppress
 from pathlib import Path
 from typing import TYPE_CHECKING
 from typing import Any
@@ -114,7 +115,11 @@ def _collect_from_tasks(session: Session) -> None:
             name = raw_task.pytask_meta.name
 
         if has_mark(raw_task, "task"):
-            COLLECTED_TASKS[path].remove(raw_task)
+            # When tasks with @task are passed to the programmatic interface multiple
+            # times, they are deleted from ``COLLECTED_TASKS`` in the first iteration
+            # and are missing in the later. See #625.
+            with suppress(ValueError):
+                COLLECTED_TASKS[path].remove(raw_task)
 
         # When a task is not a callable, it can be anything or a PTask. Set arbitrary
         # values and it will pass without errors and not collected.

tests/test_execute.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import json
+import os
 import pickle
 import re
 import subprocess
@@ -261,7 +262,15 @@ def task_example():
 
 @pytest.mark.end_to_end()
 def test_task_executed_with_force_although_unchanged(tmp_path):
-    tmp_path.joinpath("task_module.py").write_text("def task_example(): pass")
+    source = """
+    from pytask import task
+
+    def task_example(): pass
+
+    @task
+    def task_example_2(): pass
+    """
+    tmp_path.joinpath("task_module.py").write_text(textwrap.dedent(source))
     session = build(paths=tmp_path)
     assert session.execution_reports[0].outcome == TaskOutcome.SUCCESS
     session = build(paths=tmp_path, force=True)
@@ -625,6 +634,35 @@ def create_file(
     assert tmp_path.joinpath("file.txt").read_text() == "This is the text."
 
 
+@pytest.mark.end_to_end()
+@pytest.mark.skipif(
+    sys.platform == "win32" and os.environ.get("CI") == "true",
+    reason="Windows does not pick up the right Python interpreter.",
+)
+def test_execute_tasks_multiple_times_via_api(tmp_path):
+    """See #625."""
+    source = """
+    import pathlib
+    from typing_extensions import Annotated
+    from pytask import build, task
+    import sys
+
+    @task
+    def task1() -> None: pass
+    def task2() -> None: pass
+
+    if __name__ == "__main__":
+        session1 = build(tasks=[task1, task2])
+        session2 = build(tasks=[task1, task2])
+        sys.exit(session2.exit_code)
+    """
+    tmp_path.joinpath("task_module.py").write_text(textwrap.dedent(source))
+    result = subprocess.run(
+        ("python", tmp_path.joinpath("task_module.py").as_posix()), check=False
+    )
+    assert result.returncode == ExitCode.OK
+
+
 @pytest.mark.end_to_end()
 def test_pytask_on_a_module_that_uses_the_functional_api(tmp_path):
     source = """