Separate default install tag from default launch tag.

This 'fixes' issues people have where they want prerelease installer but not prerelease Python.
At 3.14's release, we'll remove the default config setting that installs 3-dev.
Fixes python#122

Author: zooba

src/manage/commands.py

@@ -22,7 +22,7 @@
 # or check out the docs for administrative controls:
 #    https://docs.python.org/using/windows
 DEFAULT_SOURCE_URL = "https://www.python.org/ftp/python/index-windows.json"
-DEFAULT_TAG = "3.14"
+DEFAULT_TAG = "3"
 
 
 # TODO: Remove the /dev/ for stable release
@@ -253,6 +253,7 @@ def execute(self):
         "fallback_source": (str, None, "env", "path", "uri"),
         "enable_shortcut_kinds": (str, config_split_append),
         "disable_shortcut_kinds": (str, config_split_append),
+        "default_install_tag": (str, None),
     },
 
     "first_run": {
@@ -792,6 +793,7 @@ class InstallCommand(BaseCommand):
     from_script = None
     enable_shortcut_kinds = None
     disable_shortcut_kinds = None
+    default_install_tag = DEFAULT_TAG
 
     def __init__(self, args, root=None):
         super().__init__(args, root)

src/manage/config.py

@@ -208,6 +208,8 @@ def resolve_config(cfg, source, relative_to, key_so_far="", schema=None, error_u
 
 def merge_config(into_cfg, from_cfg, schema, *, source="<unknown>", overwrite=False):
     for k, v in from_cfg.items():
+        if k.startswith("#"):
+            continue
         try:
             into = into_cfg[k]
         except LookupError:

src/manage/install_command.py

@@ -604,16 +604,16 @@ def execute(cmd):
     if not cmd.by_id:
         for arg in cmd.args:
             if arg.casefold() == "default".casefold():
-                LOGGER.debug("Replacing 'default' with '%s'", cmd.default_tag)
-                cmd.tags.append(tag_or_range(cmd.default_tag))
+                LOGGER.debug("Replacing 'default' with '%s'", cmd.default_install_tag)
+                cmd.tags.append(tag_or_range(cmd.default_install_tag))
             else:
                 try:
                     cmd.tags.append(tag_or_range(arg))
                 except ValueError as ex:
                     LOGGER.warn("%s", ex)
 
         if not cmd.tags and cmd.automatic:
-            cmd.tags = [tag_or_range(cmd.default_tag)]
+            cmd.tags = [tag_or_range(cmd.default_install_tag)]
     else:
         if cmd.from_script:
             raise ArgumentError("Cannot use --by-id and --from-script together")
@@ -629,9 +629,9 @@ def execute(cmd):
             try:
                 tag = cmd.tags[0]
             except IndexError:
-                if cmd.default_tag:
-                    LOGGER.debug("No tags provided, installing default tag %s", cmd.default_tag)
-                    tag = cmd.default_tag
+                if cmd.default_install_tag:
+                    LOGGER.debug("No tags provided, installing default tag %s", cmd.default_install_tag)
+                    tag = cmd.default_install_tag
                 else:
                     LOGGER.debug("No tags provided, installing first runtime in feed")
                     tag = None
@@ -671,7 +671,7 @@ def execute(cmd):
             if spec:
                 cmd.tags.append(tag_or_range(spec))
             else:
-                cmd.tags.append(tag_or_range(cmd.default_tag))
+                cmd.tags.append(tag_or_range(cmd.default_install_tag))
 
         if cmd.virtual_env:
             LOGGER.debug("Clearing virtual_env setting to avoid conflicts during install.")

src/pymanager.json

@@ -1,7 +1,10 @@
 {
     "install": {
         "source": "%PYTHON_MANAGER_SOURCE_URL%",
-        "fallback_source": "./bundled/fallback-index.json"
+        "fallback_source": "./bundled/fallback-index.json",
+
+        "#": "Install 3.14 (prerelease) by default during prerelease PyManager",
+        "default_install_tag": "3-dev"
     },
     "list": {
         "format": "%PYTHON_MANAGER_LIST_FORMAT%"