Change JDK fetch default from "auto" to "always"

The "auto" mode can still be used for on-demand fetching, but it is more
robust to fetch a JDK with known characteristics rather than relying on
whatever the user happens to have installed, regardless of Java version.

See tlambert03/bffile#16.

Author: ctrueden

src/scyjava/_jvm.py

@@ -70,7 +70,7 @@ def jvm_version() -> tuple[int, ...]:
     default_jvm_path = jpype.getDefaultJVMPath()
     if not default_jvm_path:
         raise RuntimeError("Cannot glean the default JVM path")
-    print(f"Default JVM path from JPype: {default_jvm_path}")
+    _logger.debug(f"Default JVM path from JPype: {default_jvm_path}")
 
     # Good ol' macOS! Nothing beats macOS.
     jvm_path = default_jvm_path.replace(

src/scyjava/config.py

@@ -13,7 +13,7 @@
 _logger = _logging.getLogger(__name__)
 
 # Constraints on the Java installation to be used.
-_fetch_java: str = "auto"
+_fetch_java: str = "always"
 _java_vendor: str = "zulu-jre"
 _java_version: str = "11"
 _maven_url: str = "tgz+https://archive.apache.org/dist/maven/maven-3/3.9.9/binaries/apache-maven-3.9.9-bin.tar.gz"  # noqa: E501
@@ -55,10 +55,10 @@ def set_java_constraints(
     Set constraints on the version of Java to be used.
 
     :param fetch:
-        If "auto" (default), when a JVM/or maven cannot be located on the system,
-        [`cjdk`](https://github.com/cachedjdk/cjdk) will be used to download
-        a JDK/JRE distribution and set up the JVM.
-        If "always", cjdk will always be used; if "never", cjdk will never be used.
+        If "always" (default), cjdk will always be used; if "never", cjdk will
+        never be used. If "auto", when a JVM/or maven cannot be located on the system,
+        [`cjdk`](https://github.com/cachedjdk/cjdk) will be used to download a
+        JDK/JRE distribution and set up the JVM.
     :param vendor:
         The vendor of the JDK/JRE distribution for cjdk to download and cache.
         Defaults to "zulu-jre". See the cjdk documentation for details.

tests/it/jvm_version.py

@@ -13,6 +13,7 @@
 assert_that(len(before_version)).is_greater_than_or_equal_to(1)
 assert_that(before_version[0]).is_greater_than(0)
 
+scyjava.config.set_java_constraints(fetch="never")
 scyjava.config.enable_headless_mode()
 scyjava.start_jvm()