Follow all .strftime("%Y%m%d")s with .zfill(8)

Author: JamesParrott

.github/workflows/run_checks_build_and_test.yml

@@ -58,10 +58,20 @@ jobs:
       matrix:
         python-version: [
           "3.14",
+          "3.13",
+          "3.12",
+          "3.15-dev",
+          "3.11",
+          "3.10",
+          "3.9",
         ]
         os: [
           "ubuntu-24.04",
         ]
+        include:
+          - python-version: "3.14"
+          - os: "ubuntu-latest"
+          
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/setup-python@v6
@@ -73,7 +83,6 @@ jobs:
         path: ./Pyshp
 
     - name: "Hypothesis tests"
-      if:
       uses: ./Pyshp/.github/actions/test
       with:
         extra_args: '-m hypothesis'

README.md

@@ -8,8 +8,8 @@ The Python Shapefile Library (PyShp) reads and writes ESRI Shapefiles in pure Py
 
 - **Author**: [Joel Lawhead](https://github.com/GeospatialPython)
 - **Maintainers**: [James Parrott](https://github.com/JamesParrott) & [Karim Bahgat](https://github.com/karimbahgat)
-- **Version**: 3.1.4
-- **Date**: 29th June 2026
+- **Version**: 3.1.5
+- **Date**: 22nd July 2026
 - **License**: [MIT](https://github.com/GeospatialPython/pyshp/blob/master/LICENSE.TXT)
 
 ## Contents
@@ -93,6 +93,10 @@ part of your geospatial project.
 
 # Version Changes
 
+## 3.1.5
+### Bug fix
+ - Fixed another bug causing dates before the year 1000 to be encoded as less than 8 chars under "%Y%m%d (found by [Thomas Beierlein](https://github.com/GeospatialPython/pyshp/issues/435))
+
 ## 3.1.4
 ### Bug fix
  - Fix bug causing dates supplied as length 8 strings of digits to be encoded by the custom encoding, not ascii.

changelog.txt

@@ -1,3 +1,7 @@
+VERSION 3.1.5
+2026-07-22
+	* Fixed another bug causing dates before the year 1000 to be encoded as less than 8 chars under "%Y%m%d (found by [Thomas Beierlein](https://github.com/GeospatialPython/pyshp/issues/435))
+
 
 VERSION 3.1.4
 2026-06-29

src/shapefile.py

@@ -8,7 +8,7 @@
 
 from __future__ import annotations
 
-__version__ = "3.1.4"
+__version__ = "3.1.5"
 
 import abc
 import array
@@ -4430,8 +4430,10 @@ def _record(self, record: list[RecordValue]) -> None:
                 # date: 8 bytes - date stored as a string in the format YYYYMMDD.
                 if isinstance(value, list) and len(value) == 3:
                     value = date(*value)
-                if isinstance(value, date):
-                    str_val = value.strftime("%Y%m%d")
+                if isinstance(value, date): 
+                    # In Pythons using certain glibc versions.
+                    # date.strftime does not preppend zeros. 
+                    str_val = value.strftime("%Y%m%d").zfill(8)
                     # b"".join(ord(c).to_bytes() for c in s)
                 elif value in MISSING:
                     str_val = "0" * 8  # QGIS NULL for date type

tests/hypothesis_tests.py

@@ -688,6 +688,9 @@ def test_dbf_Field_roundtrips(encoding_and_dbf_field: dict) -> None:
 
 ascii_printable = string.ascii_letters + string.digits + string.punctuation + " "
 
+def date_to_str(d: datetime.date) -> str:
+    return d.strftime("%Y%m%d").zfill(8)
+
 def record_value_for_field(name: str, field_type: str, size: int, decimal: int, encoding: str):
 
     if field_type == "C":
@@ -715,7 +718,7 @@ def record_value_for_field(name: str, field_type: str, size: int, decimal: int,
     if field_type == "L":
         return sampled_from([True, False, None])
     if field_type == "D":
-        return one_of(dates(), dates().map(lambda d: d.strftime("%Y%m%d")))
+        return one_of(dates(), dates().map(date_to_str))
 
     raise ValueError(f"Unsupported: {field_type=}")
 
@@ -771,9 +774,9 @@ def _assert_reader_matches_expected_records(r, fields, written_records):
             decimal = field["decimal"]
             if field_type == "D":
                 if isinstance(expected, datetime.date):
-                    expected = expected.strftime("%Y%m%d")
+                    expected = date_to_str(expected)
                 if isinstance(actual, datetime.date):
-                    actual = actual.strftime("%Y%m%d")
+                    actual = date_to_str(actual)
             elif field_type in ("N", "F") and decimal >= 1:
                 expected = float(format(expected, f".{decimal}f"))
             assert actual == expected, f"{actual=}, {expected=}, {field_type=}, {type(actual)=}, {type(expected)=}"