conda · travishathaway · Jul 30, 2025 · Jul 20, 2025 · Jul 20, 2025 · Jul 20, 2025
@@ -392,7 +392,7 @@ def conda_build_form(self):
         version = self.get_raw_value("version")
 
         if build:
-            assert version
+            version = version or "*"
             builder += [version, build]
         elif version:
             builder.append(version)

@@ -28,8 +28,7 @@ First, let's define what each object does:
   This query language has its own syntax and rules, detailed [here][conda_package_spec]. The
   most important fields of a `MatchSpec` object are:
   * `name`: the name of the package (e.g. `pytorch`); always expected.
-  * `version`: the version constraints (e.g. `1.8.*`); can be empty but if `build` is set, set it to
-    `*` to avoid issues with the `.conda_build_form()` method.
+  * `version`: the version constraints (e.g. `1.8.*`); can be empty. If `build` is set and `version` is not, `*` will be used as default.
   * `build`: the build string constraints (e.g. `*cuda*`); can be empty.
 
 ```{admonition} Create a MatchSpec object from a PackageRecord instance

@@ -0,0 +1,19 @@
+### Enhancements
+
+* <news item>
+
+### Bug fixes
+
+* Set default value for `version` parameter when `build` is set in `MatchSpec.conda_build_form()`. (#11200 via #15025)
+
+### Deprecations
+
+* <news item>
+
+### Docs
+
+* <news item>
+
+### Other
+
+* <news item>
@@ -1436,6 +1436,24 @@ def test_invalid_version_reports_spec(spec):
     assert spec in str(exc.value)
 
 
+@pytest.mark.parametrize(
+    "build,version,expected_result",
+    [
+        (None, None, "python"),
+        ("*123*", None, "python * *123*"),
+        (None, "3.*", "python 3.*"),
+        ("*123*", "3.17", "python 3.17 *123*"),
+    ],
+    ids=["name_only", "build_only", "version_only", "build_version"],
+)
+def test_conda_build_form(build, version, expected_result):
+    """conda_build_form method handles missing values for build and/or version gracefully"""
+    kwargs = {"build": build, "version": version}
+    # only pass values that are not None
+    kwargs = {key: value for key, value in kwargs.items() if value is not None}
+    assert MatchSpec("python", **kwargs).conda_build_form() == expected_result
+
+
 @pytest.mark.parametrize(
     "input_spec,expected_output",
     [