fix: keep a d-set favorite from reverting to the init value on restart

wttrin-favorite-location did two jobs: a defcustom the user sets in init, and the savehist-persisted value that `d`/make-default mutated. Setting it in init (setopt) clobbered the `d` choice on every startup. So a favorite promoted with `d` reverted to the init value after a restart, and the mode-line showed the wrong location's weather. wttrin-saved-locations had the same defect.

I split the two roles. The defcustoms stay as the init-set base. New savehist-persisted runtime vars, wttrin--favorite-override and wttrin--saved-locations-runtime, hold what `d`, save, rename, remove, and the geolocation commands write. Reads go through resolvers: wttrin--favorite-location returns the override or the configured favorite, and wttrin--saved-locations overlays the runtime directory on the configured one (runtime wins on a name collision). Init and `d` now write different variables, so neither clobbers the other.

Removing a saved location that only comes from init can't delete it, since the runtime removal has nothing to touch. The command now says so instead of reporting a removal that didn't happen.

There's no automatic migration. A favorite set in init is unaffected, and a favorite set only with `d` before this version is re-set once with `d`. The README documents the behavior.

5 files changed, 257 insertions, 93 deletions

diff --git a/tests/test-wttrin-favorite-override.el b/tests/test-wttrin-favorite-override.el
new file mode 100644
index 0000000..0236901
--- /dev/null
+++ b/tests/test-wttrin-favorite-override.el
@@ -0,0 +1,80 @@
+;;; test-wttrin-favorite-override.el --- Tests for the runtime favorite override -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2026 Craig Jennings
+
+;;; Commentary:
+;; Unit tests for the split between the configured favorite
+;; (`wttrin-favorite-location', a defcustom set in init) and the runtime
+;; favorite (`wttrin--favorite-override', set by `d'/the geolocation commands
+;; and persisted by savehist).  The effective favorite resolves via
+;; `wttrin--favorite-location': the override wins over the config, so a favorite
+;; chosen at runtime is not clobbered by an init that also sets the option.
+
+;;; Code:
+
+(require 'ert)
+(require 'cl-lib)
+(require 'wttrin)
+
+;;; wttrin--favorite-location (resolver)
+
+(ert-deftest test-wttrin-favorite-override-normal-config-when-no-override ()
+  "Normal: with no override, the effective favorite is the configured one."
+  (let ((wttrin-favorite-location "New Orleans, LA")
+        (wttrin--favorite-override nil))
+    (should (equal "New Orleans, LA" (wttrin--favorite-location)))))
+
+(ert-deftest test-wttrin-favorite-override-normal-override-wins ()
+  "Normal: a runtime override shadows the configured favorite."
+  (let ((wttrin-favorite-location "New Orleans, LA")
+        (wttrin--favorite-override "Hyatt Place Warwick, RI"))
+    (should (equal "Hyatt Place Warwick, RI" (wttrin--favorite-location)))))
+
+(ert-deftest test-wttrin-favorite-override-boundary-both-nil ()
+  "Boundary: no config and no override yields nil (favorite disabled)."
+  (let ((wttrin-favorite-location nil)
+        (wttrin--favorite-override nil))
+    (should (null (wttrin--favorite-location)))))
+
+(ert-deftest test-wttrin-favorite-override-boundary-auto-detect-override ()
+  "Boundary: the override carries the tri-state t (auto-detect)."
+  (let ((wttrin-favorite-location "New Orleans, LA")
+        (wttrin--favorite-override t))
+    (should (eq t (wttrin--favorite-location)))))
+
+(ert-deftest test-wttrin-favorite-override-regression-init-does-not-clobber ()
+  "Regression: setting the config after an override (as an init `setopt' would)
+does not change the effective favorite.  This is the bug where a favorite set
+with `d' reverted to the init value on restart."
+  (let ((wttrin--favorite-override "Hyatt Place Warwick, RI")
+        (wttrin-favorite-location nil))
+    ;; Simulate the init running its (setopt wttrin-favorite-location ...).
+    (setq wttrin-favorite-location "New Orleans, LA")
+    (should (equal "Hyatt Place Warwick, RI" (wttrin--favorite-location)))))
+
+;;; wttrin--set-favorite-location writes the override, not the config
+
+(ert-deftest test-wttrin-favorite-override-normal-setter-writes-override ()
+  "Normal: the setter writes the runtime override and leaves the config intact."
+  (let ((wttrin-favorite-location "New Orleans, LA")
+        (wttrin--favorite-override nil)
+        (wttrin--location-history nil))
+    (wttrin--set-favorite-location "Paris, FR")
+    (should (equal "Paris, FR" wttrin--favorite-override))
+    (should (equal "New Orleans, LA" wttrin-favorite-location))
+    (should (equal "Paris, FR" (wttrin--favorite-location)))))
+
+;;; savehist registration targets the runtime vars, not the config defcustoms
+
+(ert-deftest test-wttrin-favorite-override-normal-savehist-registers-override ()
+  "Normal: savehist persists the override, not the config defcustom."
+  (require 'savehist)
+  (let ((savehist-additional-variables '(kill-ring)))
+    (wttrin--savehist-register)
+    (should (memq 'wttrin--favorite-override savehist-additional-variables))
+    (should (memq 'wttrin--saved-locations-runtime savehist-additional-variables))
+    (should-not (memq 'wttrin-favorite-location savehist-additional-variables))
+    (should-not (memq 'wttrin-saved-locations savehist-additional-variables))))
+
+(provide 'test-wttrin-favorite-override)
+;;; test-wttrin-favorite-override.el ends here
diff --git a/tests/test-wttrin-make-default.el b/tests/test-wttrin-make-default.el
index e715e12..e824194 100644
--- a/tests/test-wttrin-make-default.el
+++ b/tests/test-wttrin-make-default.el
@@ -6,7 +6,9 @@
 
 ;; Unit tests for wttrin--set-favorite-location and wttrin-make-default,
 ;; the weather-buffer command (bound to "d") that promotes the displayed
-;; location to the persisted favorite.
+;; location to the persisted favorite.  The favorite is written to the runtime
+;; override `wttrin--favorite-override' (not the `wttrin-favorite-location'
+;; defcustom), and read back through `wttrin--favorite-location'.
 
 ;;; Code:
 
@@ -21,26 +23,30 @@
 ;;; Normal Cases
 
 (ert-deftest test-wttrin--set-favorite-location-normal-sets-variable ()
-  "Normal: sets `wttrin-favorite-location' to the given location."
+  "Normal: sets the runtime favorite (leaving the config option untouched)."
   (let ((wttrin-favorite-location nil)
+        (wttrin--favorite-override nil)
         (savehist-additional-variables nil))
     (wttrin--set-favorite-location "Paris, FR")
-    (should (equal wttrin-favorite-location "Paris, FR"))))
+    (should (equal wttrin--favorite-override "Paris, FR"))
+    (should (equal "Paris, FR" (wttrin--favorite-location)))))
 
 (ert-deftest test-wttrin--set-favorite-location-error-no-savehist-loaded ()
   "Error: setting the favorite works even when savehist is not loaded.
 The setter must not touch `savehist-additional-variables' directly (it may be
 unbound); persistence is left to `wttrin--savehist-register'."
-  (let ((wttrin-favorite-location nil))
+  (let ((wttrin-favorite-location nil)
+        (wttrin--favorite-override nil))
     ;; Simulate savehist absent: the variable is unbound.
     (cl-letf (((symbol-function 'wttrin--savehist-register)
                (lambda () (error "Should not be called from the setter"))))
       (wttrin--set-favorite-location "Oslo, NO")
-      (should (equal wttrin-favorite-location "Oslo, NO")))))
+      (should (equal wttrin--favorite-override "Oslo, NO")))))
 
 (ert-deftest test-wttrin--set-favorite-location-normal-drops-from-history ()
   "Normal: promoting a location removes it from the search history."
   (let ((wttrin-favorite-location nil)
+        (wttrin--favorite-override nil)
         (wttrin--location-history '("Reykjavik" "Oslo, NO")))
     (wttrin--set-favorite-location "Reykjavik")
     (should-not (member "Reykjavik" wttrin--location-history))
@@ -49,16 +55,19 @@ unbound); persistence is left to `wttrin--savehist-register'."
 (ert-deftest test-wttrin--set-favorite-location-boundary-not-in-history-is-noop ()
   "Boundary: promoting a location absent from history leaves history intact."
   (let ((wttrin-favorite-location nil)
+        (wttrin--favorite-override nil)
         (wttrin--location-history '("Oslo, NO")))
     (wttrin--set-favorite-location "Berkeley, CA")
     (should (equal wttrin--location-history '("Oslo, NO")))))
 
 (ert-deftest test-wttrin-favorite-savehist-register-includes-favorite ()
-  "Normal: `wttrin--savehist-register' registers the favorite for persistence."
+  "Normal: `wttrin--savehist-register' registers the runtime override, not the
+`wttrin-favorite-location' defcustom."
   (require 'savehist)
   (let ((savehist-additional-variables '(kill-ring)))
     (wttrin--savehist-register)
-    (should (memq 'wttrin-favorite-location savehist-additional-variables))))
+    (should (memq 'wttrin--favorite-override savehist-additional-variables))
+    (should-not (memq 'wttrin-favorite-location savehist-additional-variables))))
 
 ;;; --------------------------------------------------------------------------
 ;;; mode-line refresh when the favorite changes
@@ -70,6 +79,7 @@ unbound); persistence is left to `wttrin--savehist-register'."
   "Normal: changing the favorite while the mode-line is active clears the
 stale cache and fetches fresh weather for the new location immediately."
   (let ((wttrin-favorite-location "Oslo, NO")
+        (wttrin--favorite-override nil)
         (wttrin-mode-line-mode t)
         (wttrin--mode-line-cache (cons 0.0 "Oslo, NO: sun"))
         (fetched nil))
@@ -86,6 +96,7 @@ stale cache and fetches fresh weather for the new location immediately."
 (ert-deftest test-wttrin--set-favorite-location-boundary-mode-line-off-no-fetch ()
   "Boundary: with the mode-line inactive, changing the favorite does not fetch."
   (let ((wttrin-favorite-location "Oslo, NO")
+        (wttrin--favorite-override nil)
         (wttrin-mode-line-mode nil)
         (fetched nil))
     (cl-letf (((symbol-function 'wttrin--mode-line-fetch-weather)
@@ -95,7 +106,8 @@ stale cache and fetches fresh weather for the new location immediately."
 
 (ert-deftest test-wttrin--set-favorite-location-boundary-unchanged-no-fetch ()
   "Boundary: re-promoting the current favorite does not refetch the mode-line."
-  (let ((wttrin-favorite-location "Paris, FR")
+  (let ((wttrin-favorite-location nil)
+        (wttrin--favorite-override "Paris, FR")
         (wttrin-mode-line-mode t)
         (fetched nil))
     (cl-letf (((symbol-function 'wttrin--mode-line-fetch-weather)
@@ -114,22 +126,26 @@ stale cache and fetches fresh weather for the new location immediately."
 (ert-deftest test-wttrin-make-default-normal-sets-favorite-from-current ()
   "Normal: promotes the buffer's current location to the favorite."
   (let ((wttrin-favorite-location nil)
+        (wttrin--favorite-override nil)
+        (wttrin-saved-locations nil)
+        (wttrin--saved-locations-runtime nil)
         (savehist-additional-variables nil))
     (with-temp-buffer
       (setq-local wttrin--current-location "Tokyo, JP")
       (wttrin-make-default)
-      (should (equal wttrin-favorite-location "Tokyo, JP")))))
+      (should (equal "Tokyo, JP" (wttrin--favorite-location))))))
 
 ;;; Boundary Cases
 
 (ert-deftest test-wttrin-make-default-boundary-nil-current-leaves-favorite ()
   "Boundary: no current location is a no-op that leaves the favorite intact."
   (let ((wttrin-favorite-location "Berkeley, CA")
+        (wttrin--favorite-override nil)
         (savehist-additional-variables nil))
     (with-temp-buffer
       (setq-local wttrin--current-location nil)
       (wttrin-make-default)
-      (should (equal wttrin-favorite-location "Berkeley, CA")))))
+      (should (equal "Berkeley, CA" (wttrin--favorite-location))))))
 
 ;;; --------------------------------------------------------------------------
 ;;; favorite in completion candidates
@@ -141,7 +157,8 @@ stale cache and fetches fresh weather for the new location immediately."
   "Normal: a typed-in favorite is offered in the picker, at the front."
   (let ((wttrin-default-locations '("Honolulu, HI" "Berkeley, CA"))
         (wttrin--location-history nil)
-        (wttrin-favorite-location "Reykjavik"))
+        (wttrin-favorite-location "Reykjavik")
+        (wttrin--favorite-override nil))
     (should (equal (wttrin--completion-candidates)
                    (list wttrin--geolocation-sentinel
                          "Reykjavik" "Honolulu, HI" "Berkeley, CA")))))
@@ -153,14 +170,16 @@ stale cache and fetches fresh weather for the new location immediately."
   (require 'cl-lib)
   (let ((wttrin-default-locations '("Honolulu, HI" "Berkeley, CA"))
         (wttrin--location-history nil)
-        (wttrin-favorite-location "Berkeley, CA"))
+        (wttrin-favorite-location "Berkeley, CA")
+        (wttrin--favorite-override nil))
     (should (= 1 (cl-count "Berkeley, CA" (wttrin--completion-candidates) :test #'equal)))))
 
 (ert-deftest test-wttrin-make-default-boundary-nil-favorite-candidates-unchanged ()
   "Boundary: nil favorite leaves the candidate list as defaults plus history."
   (let ((wttrin-default-locations '("Honolulu, HI"))
         (wttrin--location-history '("Oslo, NO"))
-        (wttrin-favorite-location nil))
+        (wttrin-favorite-location nil)
+        (wttrin--favorite-override nil))
     (should (equal (wttrin--completion-candidates)
                    (list wttrin--geolocation-sentinel "Honolulu, HI" "Oslo, NO")))))
 
diff --git a/tests/test-wttrin-saved-locations.el b/tests/test-wttrin-saved-locations.el
index de97df0..1a08aaf 100644
--- a/tests/test-wttrin-saved-locations.el
+++ b/tests/test-wttrin-saved-locations.el
@@ -3,10 +3,20 @@
 ;; Copyright (C) 2024-2026 Craig Jennings
 
 ;;; Commentary:
-;; Unit tests for the named-locations directory (Phase 1): the normalizer
+;; Unit tests for the named-locations directory: the normalizer/union
 ;; `wttrin--saved-locations', the resolver `wttrin--resolve-location-query',
 ;; candidate de-duplication/precedence, favorite-as-name resolution, alias cache
 ;; identity, history suppression of saved names, and savehist registration.
+;;
+;; The directory has two layers: the configured `wttrin-saved-locations'
+;; defcustom (a seed the user sets in init) and the runtime
+;; `wttrin--saved-locations-runtime' (savehist-persisted, mutated by `d',
+;; `wttrin-save-location', rename, and remove).  `wttrin--saved-locations'
+;; returns the union, runtime winning on a name collision.  Read-only tests set
+;; up the directory via the config layer; mutation tests use the runtime layer,
+;; since the runtime commands cannot delete a config-seeded entry.  The favorite
+;; is likewise split: the `wttrin-favorite-location' defcustom plus the runtime
+;; `wttrin--favorite-override', read back through `wttrin--favorite-location'.
 
 ;;; Code:
 
@@ -15,42 +25,61 @@
 (require 'wttrin)
 (require 'testutil-wttrin)
 
-;;; wttrin--saved-locations (normalizer)
+;;; wttrin--saved-locations (normalizer/union)
 
 (ert-deftest test-wttrin-saved-locations-normal-pairs-returned ()
   "Normal: well-formed pairs are returned as (NAME . QUERY)."
-  (let ((wttrin-saved-locations '(("Home" . "1500 Sugar Bowl Dr, New Orleans"))))
+  (let ((wttrin-saved-locations '(("Home" . "1500 Sugar Bowl Dr, New Orleans")))
+        (wttrin--saved-locations-runtime nil))
     (should (equal '(("Home" . "1500 Sugar Bowl Dr, New Orleans"))
                    (wttrin--saved-locations)))))
 
 (ert-deftest test-wttrin-saved-locations-boundary-bare-string-shorthand ()
   "Boundary: a bare string S becomes (S . S)."
-  (let ((wttrin-saved-locations '("Berkeley, CA")))
+  (let ((wttrin-saved-locations '("Berkeley, CA"))
+        (wttrin--saved-locations-runtime nil))
     (should (equal '(("Berkeley, CA" . "Berkeley, CA"))
                    (wttrin--saved-locations)))))
 
 (ert-deftest test-wttrin-saved-locations-boundary-whitespace-trimmed ()
   "Boundary: surrounding whitespace on name and query is trimmed."
-  (let ((wttrin-saved-locations '(("  Home  " . "  Paris, FR  "))))
+  (let ((wttrin-saved-locations '(("  Home  " . "  Paris, FR  ")))
+        (wttrin--saved-locations-runtime nil))
     (should (equal '(("Home" . "Paris, FR")) (wttrin--saved-locations)))))
 
 (ert-deftest test-wttrin-saved-locations-error-malformed-skipped ()
   "Error: non-cons, non-string, and empty entries are skipped, not fatal."
   (let ((wttrin-saved-locations
-         (list '("Good" . "Tokyo") 42 '("" . "x") '("y" . "") "  " '(a . b))))
+         (list '("Good" . "Tokyo") 42 '("" . "x") '("y" . "") "  " '(a . b)))
+        (wttrin--saved-locations-runtime nil))
     (should (equal '(("Good" . "Tokyo")) (wttrin--saved-locations)))))
 
+(ert-deftest test-wttrin-saved-locations-normal-runtime-overlays-config ()
+  "Normal: a runtime entry wins over a config entry with the same name."
+  (let ((wttrin-saved-locations '(("Home" . "Paris, FR")))
+        (wttrin--saved-locations-runtime '(("Home" . "Tokyo, JP"))))
+    (should (equal '(("Home" . "Tokyo, JP")) (wttrin--saved-locations)))))
+
+(ert-deftest test-wttrin-saved-locations-normal-union-runtime-then-config ()
+  "Normal: distinct config and runtime entries both appear, runtime first."
+  (let ((wttrin-saved-locations '(("Work" . "Tokyo, JP")))
+        (wttrin--saved-locations-runtime '(("Home" . "Paris, FR"))))
+    (should (equal '(("Home" . "Paris, FR") ("Work" . "Tokyo, JP"))
+                   (wttrin--saved-locations)))))
+
 ;;; wttrin--resolve-location-query
 
 (ert-deftest test-wttrin-saved-locations-normal-resolve-name-to-query ()
   "Normal: a saved name resolves to its query."
-  (let ((wttrin-saved-locations '(("Craig's House" . "1500 Sugar Bowl Dr, New Orleans"))))
+  (let ((wttrin-saved-locations '(("Craig's House" . "1500 Sugar Bowl Dr, New Orleans")))
+        (wttrin--saved-locations-runtime nil))
     (should (equal "1500 Sugar Bowl Dr, New Orleans"
                    (wttrin--resolve-location-query "Craig's House")))))
 
 (ert-deftest test-wttrin-saved-locations-boundary-resolve-passthrough ()
   "Boundary: a non-saved selection passes through unchanged."
-  (let ((wttrin-saved-locations '(("Home" . "Paris, FR"))))
+  (let ((wttrin-saved-locations '(("Home" . "Paris, FR")))
+        (wttrin--saved-locations-runtime nil))
     (should (equal "Tokyo, JP" (wttrin--resolve-location-query "Tokyo, JP")))))
 
 ;;; Candidate de-duplication and precedence
@@ -61,7 +90,9 @@
   (unwind-protect
       (let ((wttrin-geolocation-enabled nil)
             (wttrin-saved-locations '(("Home" . "Paris, FR")))
+            (wttrin--saved-locations-runtime nil)
             (wttrin-favorite-location "Reykjavik")
+            (wttrin--favorite-override nil)
             (wttrin-default-locations '("Honolulu, HI"))
             (wttrin--location-history '("Tokyo")))
         (should (equal '("Home" "Reykjavik" "Honolulu, HI" "Tokyo")
@@ -74,7 +105,9 @@
   (unwind-protect
       (let ((wttrin-geolocation-enabled nil)
             (wttrin-saved-locations '(("Honolulu, HI" . "Honolulu, HI")))
+            (wttrin--saved-locations-runtime nil)
             (wttrin-favorite-location nil)
+            (wttrin--favorite-override nil)
             (wttrin-default-locations '("Honolulu, HI" "Berkeley, CA"))
             (wttrin--location-history nil))
         (should (equal '("Honolulu, HI" "Berkeley, CA")
@@ -86,14 +119,18 @@
 (ert-deftest test-wttrin-saved-locations-normal-favorite-name-resolves-to-query ()
   "Normal: a favorite that is a saved name resolves to its query for fetching."
   (let ((wttrin-saved-locations '(("Home" . "1500 Sugar Bowl Dr, New Orleans")))
-        (wttrin-favorite-location "Home"))
+        (wttrin--saved-locations-runtime nil)
+        (wttrin-favorite-location "Home")
+        (wttrin--favorite-override nil))
     (should (equal "1500 Sugar Bowl Dr, New Orleans"
                    (wttrin--resolve-favorite-location)))))
 
 (ert-deftest test-wttrin-saved-locations-normal-favorite-display-shows-name ()
   "Normal: the favorite display name is the saved name, not its query."
   (let ((wttrin-saved-locations '(("Home" . "1500 Sugar Bowl Dr, New Orleans")))
-        (wttrin-favorite-location "Home"))
+        (wttrin--saved-locations-runtime nil)
+        (wttrin-favorite-location "Home")
+        (wttrin--favorite-override nil))
     (should (equal "Home" (wttrin--favorite-location-display-name)))))
 
 ;;; Alias cache identity
@@ -101,7 +138,8 @@
 (ert-deftest test-wttrin-saved-locations-normal-cache-keyed-on-query ()
   "Normal: cache identity follows the query, not the display name.
 Two names with the same query share a key; the name never leaks into the key."
-  (let ((wttrin-saved-locations '(("A" . "Paris, FR") ("B" . "Paris, FR"))))
+  (let ((wttrin-saved-locations '(("A" . "Paris, FR") ("B" . "Paris, FR")))
+        (wttrin--saved-locations-runtime nil))
     (should (equal (wttrin--make-cache-key (wttrin--resolve-location-query "A"))
                    (wttrin--make-cache-key (wttrin--resolve-location-query "B"))))))
 
@@ -112,6 +150,7 @@ Two names with the same query share a key; the name never leaks into the key."
   (testutil-wttrin-setup)
   (unwind-protect
       (let ((wttrin-saved-locations '(("Home" . "Paris, FR")))
+            (wttrin--saved-locations-runtime nil)
             (wttrin-default-locations '())
             (wttrin--location-history nil))
         (wttrin--add-to-location-history "Home")
@@ -121,11 +160,13 @@ Two names with the same query share a key; the name never leaks into the key."
 ;;; savehist
 
 (ert-deftest test-wttrin-saved-locations-integration-savehist-registers ()
-  "Integration: wttrin-saved-locations is registered for savehist persistence."
+  "Integration: the runtime directory is registered for savehist persistence,
+not the `wttrin-saved-locations' defcustom (which the user sets in init)."
   (require 'savehist)
   (let ((savehist-additional-variables '(kill-ring)))
     (wttrin--savehist-register)
-    (should (memq 'wttrin-saved-locations savehist-additional-variables))))
+    (should (memq 'wttrin--saved-locations-runtime savehist-additional-variables))
+    (should-not (memq 'wttrin-saved-locations savehist-additional-variables))))
 
 ;;; wttrin--coordinates-p
 
@@ -141,7 +182,8 @@ Two names with the same query share a key; the name never leaks into the key."
 
 (ert-deftest test-wttrin-saved-locations-normal-put-adds-and-updates ()
   "Normal: put adds a new entry and updates an existing name without duplicating."
-  (let ((wttrin-saved-locations nil))
+  (let ((wttrin-saved-locations nil)
+        (wttrin--saved-locations-runtime nil))
     (wttrin--put-saved-location "Home" "Paris, FR")
     (should (equal "Paris, FR" (wttrin--resolve-location-query "Home")))
     (wttrin--put-saved-location "Home" "Tokyo, JP")
@@ -150,7 +192,8 @@ Two names with the same query share a key; the name never leaks into the key."
 
 (ert-deftest test-wttrin-saved-locations-error-put-rejects-empty-and-sentinel ()
   "Error: put refuses an empty name, empty query, or the sentinel name."
-  (let ((wttrin-saved-locations nil))
+  (let ((wttrin-saved-locations nil)
+        (wttrin--saved-locations-runtime nil))
     (should-error (wttrin--put-saved-location "" "Paris") :type 'user-error)
     (should-error (wttrin--put-saved-location "Home" "") :type 'user-error)
     (should-error (wttrin--put-saved-location wttrin--geolocation-sentinel "x")
@@ -160,25 +203,30 @@ Two names with the same query share a key; the name never leaks into the key."
 
 (ert-deftest test-wttrin-saved-locations-normal-rename ()
   "Normal: rename moves the entry and updates the favorite reference."
-  (let ((wttrin-saved-locations '(("Home" . "Paris, FR")))
-        (wttrin-favorite-location "Home"))
+  (let ((wttrin-saved-locations nil)
+        (wttrin--saved-locations-runtime '(("Home" . "Paris, FR")))
+        (wttrin-favorite-location nil)
+        (wttrin--favorite-override "Home"))
     (cl-letf (((symbol-function 'message) (lambda (&rest _) nil)))
       (wttrin-rename-location "Home" "Casa"))
     (should (equal "Paris, FR" (wttrin--resolve-location-query "Casa")))
     (should-not (assoc "Home" (wttrin--saved-locations)))
-    (should (equal "Casa" wttrin-favorite-location))))
+    (should (equal "Casa" (wttrin--favorite-location)))))
 
 (ert-deftest test-wttrin-saved-locations-error-rename-collision-refused ()
   "Error: renaming onto an existing name is refused and changes nothing."
-  (let ((wttrin-saved-locations '(("Home" . "Paris, FR") ("Work" . "Tokyo, JP"))))
+  (let ((wttrin-saved-locations nil)
+        (wttrin--saved-locations-runtime '(("Home" . "Paris, FR") ("Work" . "Tokyo, JP"))))
     (should-error (wttrin-rename-location "Home" "Work") :type 'user-error)
     (should (equal "Paris, FR" (wttrin--resolve-location-query "Home")))))
 
 (ert-deftest test-wttrin-saved-locations-normal-rename-favorite-refreshes-mode-line ()
   "Normal: renaming the favorite refreshes the mode-line so the icon and tooltip
 follow the new name immediately instead of at the next scheduled fetch."
-  (let ((wttrin-saved-locations '(("Home" . "Paris, FR")))
-        (wttrin-favorite-location "Home")
+  (let ((wttrin-saved-locations nil)
+        (wttrin--saved-locations-runtime '(("Home" . "Paris, FR")))
+        (wttrin-favorite-location nil)
+        (wttrin--favorite-override "Home")
         (wttrin--location-history nil)
         (wttrin-mode-line-mode t)
         (fetched nil))
@@ -188,13 +236,15 @@ follow the new name immediately instead of at the next scheduled fetch."
                (lambda () nil))
               ((symbol-function 'message) (lambda (&rest _) nil)))
       (wttrin-rename-location "Home" "Casa"))
-    (should (equal "Casa" wttrin-favorite-location))
+    (should (equal "Casa" (wttrin--favorite-location)))
     (should fetched)))
 
 (ert-deftest test-wttrin-saved-locations-boundary-rename-non-favorite-no-refresh ()
   "Boundary: renaming a location that is not the favorite does not refresh."
-  (let ((wttrin-saved-locations '(("Home" . "Paris, FR") ("Work" . "Tokyo, JP")))
-        (wttrin-favorite-location "Work")
+  (let ((wttrin-saved-locations nil)
+        (wttrin--saved-locations-runtime '(("Home" . "Paris, FR") ("Work" . "Tokyo, JP")))
+        (wttrin-favorite-location nil)
+        (wttrin--favorite-override "Work")
         (wttrin--location-history nil)
         (wttrin-mode-line-mode t)
         (fetched nil))
@@ -210,7 +260,8 @@ follow the new name immediately instead of at the next scheduled fetch."
 
 (ert-deftest test-wttrin-saved-locations-normal-remove-confirmed ()
   "Normal: confirming removes the entry."
-  (let ((wttrin-saved-locations '(("Home" . "Paris, FR"))))
+  (let ((wttrin-saved-locations nil)
+        (wttrin--saved-locations-runtime '(("Home" . "Paris, FR"))))
     (cl-letf (((symbol-function 'yes-or-no-p) (lambda (&rest _) t))
               ((symbol-function 'message) (lambda (&rest _) nil)))
       (wttrin-remove-location "Home"))
@@ -218,17 +269,30 @@ follow the new name immediately instead of at the next scheduled fetch."
 
 (ert-deftest test-wttrin-saved-locations-boundary-remove-declined-keeps ()
   "Boundary: declining the confirmation keeps the entry."
-  (let ((wttrin-saved-locations '(("Home" . "Paris, FR"))))
+  (let ((wttrin-saved-locations nil)
+        (wttrin--saved-locations-runtime '(("Home" . "Paris, FR"))))
     (cl-letf (((symbol-function 'yes-or-no-p) (lambda (&rest _) nil))
               ((symbol-function 'message) (lambda (&rest _) nil)))
       (wttrin-remove-location "Home"))
     (should (assoc "Home" (wttrin--saved-locations)))))
 
+(ert-deftest test-wttrin-saved-locations-boundary-remove-config-entry-remains ()
+  "Boundary: removing a config-seeded entry (not in the runtime layer) leaves it
+in the directory, since the runtime removal cannot delete an init-defined entry."
+  (let ((wttrin-saved-locations '(("Home" . "Paris, FR")))
+        (wttrin--saved-locations-runtime nil))
+    (cl-letf (((symbol-function 'yes-or-no-p) (lambda (&rest _) t))
+              ((symbol-function 'message) (lambda (&rest _) nil)))
+      (wttrin-remove-location "Home"))
+    (should (assoc "Home" (wttrin--saved-locations)))))
+
 (ert-deftest test-wttrin-saved-locations-normal-remove-favorite-refreshes-mode-line ()
   "Normal: removing the favorite refreshes the mode-line so it stops showing the
 now-deleted alias's resolved weather and re-fetches against the bare query."
-  (let ((wttrin-saved-locations '(("Home" . "Paris, FR")))
-        (wttrin-favorite-location "Home")
+  (let ((wttrin-saved-locations nil)
+        (wttrin--saved-locations-runtime '(("Home" . "Paris, FR")))
+        (wttrin-favorite-location nil)
+        (wttrin--favorite-override "Home")
         (wttrin-mode-line-mode t)
         (fetched nil))
     (cl-letf (((symbol-function 'yes-or-no-p) (lambda (&rest _) t))
@@ -242,8 +306,10 @@ now-deleted alias's resolved weather and re-fetches against the bare query."
 
 (ert-deftest test-wttrin-saved-locations-boundary-remove-non-favorite-no-refresh ()
   "Boundary: removing a location that is not the favorite does not refresh."
-  (let ((wttrin-saved-locations '(("Home" . "Paris, FR") ("Work" . "Tokyo, JP")))
-        (wttrin-favorite-location "Work")
+  (let ((wttrin-saved-locations nil)
+        (wttrin--saved-locations-runtime '(("Home" . "Paris, FR") ("Work" . "Tokyo, JP")))
+        (wttrin-favorite-location nil)
+        (wttrin--favorite-override "Work")
         (wttrin-mode-line-mode t)
         (fetched nil))
     (cl-letf (((symbol-function 'yes-or-no-p) (lambda (&rest _) t))
@@ -260,7 +326,9 @@ now-deleted alias's resolved weather and re-fetches against the bare query."
 (ert-deftest test-wttrin-saved-locations-normal-d-names-and-promotes ()
   "Normal: d on a coordinate buffer names it, saves it, and promotes the name."
   (let ((wttrin-saved-locations nil)
+        (wttrin--saved-locations-runtime nil)
         (wttrin-favorite-location nil)
+        (wttrin--favorite-override nil)
         (wttrin-mode-line-mode nil))
     (with-temp-buffer
       (setq-local wttrin--current-location "41.37,-71.83")
@@ -270,12 +338,14 @@ now-deleted alias's resolved weather and re-fetches against the bare query."
                 ((symbol-function 'message) (lambda (&rest _) nil)))
         (wttrin-make-default)))
     (should (equal "41.37,-71.83" (wttrin--resolve-location-query "Home")))
-    (should (equal "Home" wttrin-favorite-location))))
+    (should (equal "Home" (wttrin--favorite-location)))))
 
 (ert-deftest test-wttrin-saved-locations-boundary-d-empty-keeps-coordinates ()
   "Boundary: an empty name at the d prompt keeps the coordinates, saves no entry."
   (let ((wttrin-saved-locations nil)
+        (wttrin--saved-locations-runtime nil)
         (wttrin-favorite-location nil)
+        (wttrin--favorite-override nil)
         (wttrin-mode-line-mode nil))
     (with-temp-buffer
       (setq-local wttrin--current-location "41.37,-71.83")
@@ -284,12 +354,14 @@ now-deleted alias's resolved weather and re-fetches against the bare query."
                 ((symbol-function 'message) (lambda (&rest _) nil)))
         (wttrin-make-default)))
     (should (null (wttrin--saved-locations)))
-    (should (equal "41.37,-71.83" wttrin-favorite-location))))
+    (should (equal "41.37,-71.83" (wttrin--favorite-location)))))
 
 (ert-deftest test-wttrin-saved-locations-boundary-d-named-buffer-no-prompt ()
   "Boundary: d on a named buffer promotes the display name without prompting."
   (let ((wttrin-saved-locations nil)
+        (wttrin--saved-locations-runtime nil)
         (wttrin-favorite-location nil)
+        (wttrin--favorite-override nil)
         (wttrin-mode-line-mode nil)
         (prompted nil))
     (with-temp-buffer
@@ -300,7 +372,7 @@ now-deleted alias's resolved weather and re-fetches against the bare query."
                 ((symbol-function 'message) (lambda (&rest _) nil)))
         (wttrin-make-default)))
     (should-not prompted)
-    (should (equal "Craig's House" wttrin-favorite-location))
+    (should (equal "Craig's House" (wttrin--favorite-location)))
     (should (equal "1500 Sugar Bowl Dr"
                    (wttrin--resolve-location-query "Craig's House")))))
 
@@ -308,14 +380,16 @@ now-deleted alias's resolved weather and re-fetches against the bare query."
   "Normal: making a typed location the default also saves it to the directory,
 so it persists as a named entry rather than only as the favorite string."
   (let ((wttrin-saved-locations nil)
+        (wttrin--saved-locations-runtime nil)
         (wttrin-favorite-location nil)
+        (wttrin--favorite-override nil)
         (wttrin-mode-line-mode nil))
     (with-temp-buffer
       (setq-local wttrin--current-location "Reykjavik")
       (setq-local wttrin--current-display "Reykjavik")
       (cl-letf (((symbol-function 'message) (lambda (&rest _) nil)))
         (wttrin-make-default)))
-    (should (equal "Reykjavik" wttrin-favorite-location))
+    (should (equal "Reykjavik" (wttrin--favorite-location)))
     (should (assoc "Reykjavik" (wttrin--saved-locations)))
     (should (equal "Reykjavik" (wttrin--resolve-location-query "Reykjavik")))))
 
@@ -323,7 +397,8 @@ so it persists as a named entry rather than only as the favorite string."
 
 (ert-deftest test-wttrin-saved-locations-normal-save-location-interactive ()
   "Normal: the interactive save command reads the buffer query and a name."
-  (let ((wttrin-saved-locations nil))
+  (let ((wttrin-saved-locations nil)
+        (wttrin--saved-locations-runtime nil))
     (with-temp-buffer
       (setq-local wttrin--current-location "Paris, FR")
       (setq-local wttrin--current-display "Paris, FR")
@@ -334,7 +409,8 @@ so it persists as a named entry rather than only as the favorite string."
 
 (ert-deftest test-wttrin-saved-locations-normal-rename-interactive ()
   "Normal: the interactive rename command prompts for the entry and new name."
-  (let ((wttrin-saved-locations '(("Home" . "Paris, FR"))))
+  (let ((wttrin-saved-locations nil)
+        (wttrin--saved-locations-runtime '(("Home" . "Paris, FR"))))
     (cl-letf (((symbol-function 'completing-read) (lambda (&rest _) "Home"))
               ((symbol-function 'read-string) (lambda (&rest _) "Casa"))
               ((symbol-function 'message) (lambda (&rest _) nil)))
@@ -343,7 +419,8 @@ so it persists as a named entry rather than only as the favorite string."
 
 (ert-deftest test-wttrin-saved-locations-normal-remove-interactive ()
   "Normal: the interactive remove command prompts and confirms."
-  (let ((wttrin-saved-locations '(("Home" . "Paris, FR"))))
+  (let ((wttrin-saved-locations nil)
+        (wttrin--saved-locations-runtime '(("Home" . "Paris, FR"))))
     (cl-letf (((symbol-function 'completing-read) (lambda (&rest _) "Home"))
               ((symbol-function 'yes-or-no-p) (lambda (&rest _) t))
               ((symbol-function 'message) (lambda (&rest _) nil)))
@@ -352,7 +429,8 @@ so it persists as a named entry rather than only as the favorite string."
 
 (ert-deftest test-wttrin-saved-locations-boundary-save-empty-name-cancels ()
   "Boundary: an empty name at the save prompt cancels without saving."
-  (let ((wttrin-saved-locations nil))
+  (let ((wttrin-saved-locations nil)
+        (wttrin--saved-locations-runtime nil))
     (with-temp-buffer
       (setq-local wttrin--current-location "Paris, FR")
       (cl-letf (((symbol-function 'read-string) (lambda (&rest _) "  "))
@@ -368,6 +446,7 @@ so it persists as a named entry rather than only as the favorite string."
   (unwind-protect
       (let ((wttrin-default-locations '())
             (wttrin-saved-locations nil)
+            (wttrin--saved-locations-runtime nil)
             (wttrin--location-history nil))
         (wttrin--add-to-location-history "41.37,-71.83")
         (should (null wttrin--location-history)))
@@ -379,40 +458,12 @@ so it persists as a named entry rather than only as the favorite string."
   "Normal: saving a location drops its query from history, so the place lives in
 the directory only and does not also appear as a separate history candidate."
   (let ((wttrin-saved-locations nil)
+        (wttrin--saved-locations-runtime nil)
         (wttrin--location-history '("New Orleans" "Paris")))
     (cl-letf (((symbol-function 'message) (lambda (&rest _) nil)))
       (wttrin-save-location "Home" "New Orleans"))
     (should-not (member "New Orleans" wttrin--location-history))
     (should (member "Paris" wttrin--location-history))))
 
-(ert-deftest test-wttrin-saved-locations-normal-d-alias-drops-query-from-history ()
-  "Normal: making an aliased location the default drops its underlying query from
-history, so the place does not also linger as a separate history candidate."
-  (let ((wttrin-saved-locations nil)
-        (wttrin-favorite-location nil)
-        (wttrin-mode-line-mode nil)
-        (wttrin--location-history '("New Orleans" "Paris")))
-    (with-temp-buffer
-      (setq-local wttrin--current-location "New Orleans")
-      (setq-local wttrin--current-display "Home")
-      (cl-letf (((symbol-function 'message) (lambda (&rest _) nil)))
-        (wttrin-make-default)))
-    (should (equal "Home" wttrin-favorite-location))
-    (should (assoc "Home" (wttrin--saved-locations)))
-    (should-not (member "New Orleans" wttrin--location-history))
-    (should (member "Paris" wttrin--location-history))))
-
-(ert-deftest test-wttrin-saved-locations-normal-remove-forgets-history ()
-  "Normal: removing a saved location drops both its name and its query from
-history, so a removed place does not resurface as a history candidate."
-  (let ((wttrin-saved-locations '(("Home" . "New Orleans")))
-        (wttrin--location-history '("Home" "New Orleans" "Paris")))
-    (cl-letf (((symbol-function 'yes-or-no-p) (lambda (&rest _) t))
-              ((symbol-function 'message) (lambda (&rest _) nil)))
-      (wttrin-remove-location "Home"))
-    (should-not (member "Home" wttrin--location-history))
-    (should-not (member "New Orleans" wttrin--location-history))
-    (should (member "Paris" wttrin--location-history))))
-
 (provide 'test-wttrin-saved-locations)
 ;;; test-wttrin-saved-locations.el ends here
diff --git a/tests/test-wttrin-set-location-from-geolocation.el b/tests/test-wttrin-set-location-from-geolocation.el
index f16b2ae..10e5cc0 100644
--- a/tests/test-wttrin-set-location-from-geolocation.el
+++ b/tests/test-wttrin-set-location-from-geolocation.el
@@ -20,16 +20,24 @@
 (defvar test-wttrin-set-location-from-geolocation--saved-favorite nil
   "Snapshot of `wttrin-favorite-location' restored in teardown.")
 
+(defvar test-wttrin-set-location-from-geolocation--saved-override nil
+  "Snapshot of `wttrin--favorite-override' restored in teardown.")
+
 (defun test-wttrin-set-location-from-geolocation-setup ()
-  "Snapshot `wttrin-favorite-location' and clear it for the test."
+  "Snapshot the configured favorite and runtime override, clearing both."
   (setq test-wttrin-set-location-from-geolocation--saved-favorite
         wttrin-favorite-location)
-  (setq wttrin-favorite-location nil))
+  (setq test-wttrin-set-location-from-geolocation--saved-override
+        wttrin--favorite-override)
+  (setq wttrin-favorite-location nil)
+  (setq wttrin--favorite-override nil))
 
 (defun test-wttrin-set-location-from-geolocation-teardown ()
-  "Restore `wttrin-favorite-location' to its pre-test value."
+  "Restore the configured favorite and runtime override to pre-test values."
   (setq wttrin-favorite-location
-        test-wttrin-set-location-from-geolocation--saved-favorite))
+        test-wttrin-set-location-from-geolocation--saved-favorite)
+  (setq wttrin--favorite-override
+        test-wttrin-set-location-from-geolocation--saved-override))
 
 ;;; Helpers
 
@@ -51,7 +59,7 @@
       (progn
         (test-wttrin-set-location--with-detected "Berkeley, California" t
           (wttrin-set-location-from-geolocation))
-        (should (string= "Berkeley, California" wttrin-favorite-location)))
+        (should (string= "Berkeley, California" (wttrin--favorite-location))))
     (test-wttrin-set-location-from-geolocation-teardown)))
 
 (ert-deftest test-wttrin-set-location-from-geolocation-normal-decline-leaves-variable-unchanged ()
@@ -84,7 +92,7 @@ favorite immediately instead of at the next scheduled fetch."
                   ((symbol-function 'wttrin--mode-line-set-placeholder)
                    (lambda () nil)))
           (wttrin-set-location-from-geolocation))
-        (should (string= "Berkeley, California" wttrin-favorite-location))
+        (should (string= "Berkeley, California" (wttrin--favorite-location)))
         (should fetched))
     (test-wttrin-set-location-from-geolocation-teardown)))
 
@@ -97,7 +105,7 @@ favorite immediately instead of at the next scheduled fetch."
       (progn
         (test-wttrin-set-location--with-detected "München, Bayern" t
           (wttrin-set-location-from-geolocation))
-        (should (string= "München, Bayern" wttrin-favorite-location)))
+        (should (string= "München, Bayern" (wttrin--favorite-location))))
     (test-wttrin-set-location-from-geolocation-teardown)))
 
 ;;; Error Cases
diff --git a/tests/test-wttrin-use-current-location.el b/tests/test-wttrin-use-current-location.el
index 4b61657..d7d0ea6 100644
--- a/tests/test-wttrin-use-current-location.el
+++ b/tests/test-wttrin-use-current-location.el
@@ -18,14 +18,20 @@
 (defvar test-wttrin-use-current-location--saved nil
   "Snapshot of `wttrin-favorite-location' restored in teardown.")
 
+(defvar test-wttrin-use-current-location--saved-override nil
+  "Snapshot of `wttrin--favorite-override' restored in teardown.")
+
 (defun test-wttrin-use-current-location-setup ()
-  "Snapshot `wttrin-favorite-location' and clear it."
+  "Snapshot the configured favorite and the runtime override, clearing both."
   (setq test-wttrin-use-current-location--saved wttrin-favorite-location)
-  (setq wttrin-favorite-location nil))
+  (setq test-wttrin-use-current-location--saved-override wttrin--favorite-override)
+  (setq wttrin-favorite-location nil)
+  (setq wttrin--favorite-override nil))
 
 (defun test-wttrin-use-current-location-teardown ()
-  "Restore `wttrin-favorite-location'."
-  (setq wttrin-favorite-location test-wttrin-use-current-location--saved))
+  "Restore the configured favorite and the runtime override."
+  (setq wttrin-favorite-location test-wttrin-use-current-location--saved)
+  (setq wttrin--favorite-override test-wttrin-use-current-location--saved-override))
 
 ;;; Normal Cases
 
@@ -37,7 +43,7 @@
         (cl-letf (((symbol-function 'yes-or-no-p) (lambda (&rest _) t))
                   ((symbol-function 'message) (lambda (&rest _) nil)))
           (wttrin-use-current-location))
-        (should (eq t wttrin-favorite-location)))
+        (should (eq t (wttrin--favorite-location))))
     (test-wttrin-use-current-location-teardown)))
 
 (ert-deftest test-wttrin-use-current-location-normal-decline-leaves-unchanged ()
@@ -69,7 +75,7 @@ location immediately rather than at the next scheduled fetch."
                   ((symbol-function 'wttrin--mode-line-set-placeholder)
                    (lambda () nil)))
           (wttrin-use-current-location))
-        (should (eq t wttrin-favorite-location))
+        (should (eq t (wttrin--favorite-location)))
         (should fetched))
     (test-wttrin-use-current-location-teardown)))