diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -53,7 +53,6 @@ from . import (
     phases,
     pycompat,
     registrar,
-    requirements,
     revsetlang,
     rewriteutil,
     scmutil,
@@ -61,15 +60,16 @@ from . import (
     shelve as shelvemod,
     state as statemod,
     tags as tagsmod,
-    ui as uimod,
     util,
     verify as verifymod,
-    vfs as vfsmod,
     wireprotoserver,
 )
 
 from .cmd_impls import graft as graft_impl
-from .configuration import rcutil
+from .configuration import (
+    command as config_command,
+    rcutil,
+)
 from .utils import (
     dateutil,
     procutil,
@@ -2367,58 +2367,9 @@ def config(ui, repo, *values, **opts):
     Returns 0 on success, 1 if NAME does not exist.
 
     """
-
-    editopts = ('edit', 'local', 'global', 'shared', 'non_shared')
-    if any(opts.get(o) for o in editopts):
-        cmdutil.check_at_most_one_arg(opts, *editopts[1:])
-        if opts.get('local'):
-            if not repo:
-                raise error.InputError(
-                    _(b"can't use --local outside a repository")
-                )
-            paths = [repo.vfs.join(b'hgrc')]
-        elif opts.get('global'):
-            paths = rcutil.systemrcpath()
-        elif opts.get('shared'):
-            if not repo.shared():
-                raise error.InputError(
-                    _(b"repository is not shared; can't use --shared")
-                )
-            if requirements.SHARESAFE_REQUIREMENT not in repo.requirements:
-                raise error.InputError(
-                    _(
-                        b"share safe feature not enabled; "
-                        b"unable to edit shared source repository config"
-                    )
-                )
-            paths = [vfsmod.vfs(repo.sharedpath).join(b'hgrc')]
-        elif opts.get('non_shared'):
-            paths = [repo.vfs.join(b'hgrc-not-shared')]
-        else:
-            paths = rcutil.userrcpath()
-
-        for f in paths:
-            if os.path.exists(f):
-                break
-        else:
-            if opts.get('global'):
-                samplehgrc = uimod.samplehgrcs[b'global']
-            elif opts.get('local'):
-                samplehgrc = uimod.samplehgrcs[b'local']
-            else:
-                samplehgrc = uimod.samplehgrcs[b'user']
-
-            f = paths[0]
-            util.writefile(f, util.tonativeeol(samplehgrc))
-
-        editor = ui.geteditor()
-        ui.system(
-            b"%s \"%s\"" % (editor, f),
-            onerr=error.InputError,
-            errprefix=_(b"edit failed"),
-            blockedtag=b'config_edit',
-        )
-        return
+    edit_level = config_command.find_edit_level(ui, repo, opts)
+    if edit_level is not None:
+        return config_command.edit_config(ui, repo, edit_level)
     ui.pager(b'config')
     fm = ui.formatter(b'config', pycompat.byteskwargs(opts))
     for t, f in rcutil.rccomponents():
diff --git a/mercurial/configuration/command.py b/mercurial/configuration/command.py
new file mode 100644
--- /dev/null
+++ b/mercurial/configuration/command.py
@@ -0,0 +1,108 @@
+# Gather code related to command dealing with configuration.
+
+from __future__ import annotations
+
+import os
+
+from typing import Any, Dict, Optional
+
+from ..i18n import _
+
+from .. import (
+    cmdutil,
+    error,
+    requirements,
+    ui as uimod,
+    util,
+    vfs as vfsmod,
+)
+
+from . import rcutil
+
+EDIT_FLAG = 'edit'
+
+
+# keep typing simple for now
+ConfigLevelT = str
+LEVEL_USER = 'user'  # "user" is the default level and never passed explicitly
+LEVEL_LOCAL = 'local'
+LEVEL_GLOBAL = 'global'
+LEVEL_SHARED = 'shared'
+LEVEL_NON_SHARED = 'non_shared'
+EDIT_LEVELS = (
+    LEVEL_USER,
+    LEVEL_LOCAL,
+    LEVEL_GLOBAL,
+    LEVEL_SHARED,
+    LEVEL_NON_SHARED,
+)
+
+
+def find_edit_level(
+    ui: uimod.ui, repo, opts: Dict[str, Any]
+) -> Optional[ConfigLevelT]:
+    """return the level we should edit, if any.
+
+    Parse the command option to detect when an edit is requested, and if so the
+    configuration level we should edit.
+    """
+    if opts.get(EDIT_FLAG) or any(opts.get(o) for o in EDIT_LEVELS):
+        cmdutil.check_at_most_one_arg(opts, *EDIT_LEVELS)
+        for level in EDIT_LEVELS:
+            if opts.get(level):
+                return level
+        return EDIT_LEVELS[0]
+    return None
+
+
+def edit_config(ui: uimod.ui, repo, level: ConfigLevelT) -> None:
+    """let the user edit configuration file for the given level"""
+
+    if level == LEVEL_USER:
+        paths = rcutil.userrcpath()
+    elif level == LEVEL_GLOBAL:
+        paths = rcutil.systemrcpath()
+    elif level == LEVEL_LOCAL:
+        if not repo:
+            raise error.InputError(_(b"can't use --local outside a repository"))
+        paths = [repo.vfs.join(b'hgrc')]
+    elif level == LEVEL_NON_SHARED:
+        paths = [repo.vfs.join(b'hgrc-not-shared')]
+    elif level == LEVEL_SHARED:
+        if not repo.shared():
+            raise error.InputError(
+                _(b"repository is not shared; can't use --shared")
+            )
+        if requirements.SHARESAFE_REQUIREMENT not in repo.requirements:
+            raise error.InputError(
+                _(
+                    b"share safe feature not enabled; "
+                    b"unable to edit shared source repository config"
+                )
+            )
+        paths = [vfsmod.vfs(repo.sharedpath).join(b'hgrc')]
+    else:
+        msg = 'unknown config level: %s' % level
+        raise error.ProgrammingError(msg)
+
+    for f in paths:
+        if os.path.exists(f):
+            break
+    else:
+        if LEVEL_GLOBAL:
+            samplehgrc = uimod.samplehgrcs[b'global']
+        elif LEVEL_LOCAL:
+            samplehgrc = uimod.samplehgrcs[b'local']
+        else:
+            samplehgrc = uimod.samplehgrcs[b'user']
+
+        f = paths[0]
+        util.writefile(f, util.tonativeeol(samplehgrc))
+
+    editor = ui.geteditor()
+    ui.system(
+        b"%s \"%s\"" % (editor, f),
+        onerr=error.InputError,
+        errprefix=_(b"edit failed"),
+        blockedtag=b'config_edit',
+    )