Decouple module downloads from package version

README.md

@@ -80,7 +80,8 @@ pre-built binary** or **compile from source** (controlled by
 `ghostel-module-auto-install`, default `ask`).  You can also trigger these
 manually:
 
-- `M-x ghostel-download-module` — download a pre-built binary from GitHub releases
+- `M-x ghostel-download-module` — download the minimum supported pre-built binary
+- `C-u M-x ghostel-download-module` — choose a specific release tag (leave blank for latest)
 - `M-x ghostel-module-compile` — build from source via `zig build`
 
 ## Building from source
@@ -116,10 +117,10 @@ zig build -Doptimize=ReleaseFast
 
 When installed from MELPA, `M-x ghostel-module-compile` builds the native
 module from source using `zig build`.  Zig's package manager fetches the
-ghostty dependency automatically — no git submodule needed.
+ghostty dependency automatically.
 
-Alternatively, download a **pre-built binary** via
-`M-x ghostel-download-module`.
+Alternatively, download a **pre-built binary** via `M-x ghostel-download-module`
+(or `C-u M-x ghostel-download-module` to pick a specific release).
 
 ## Shell Integration
 

ghostel.el

@@ -374,9 +374,11 @@ before sending the input."
    ghostel-color-bright-white]
   "Color palette for the terminal (vector of 16 face names).")
 
-(defvar ghostel-github-release-url
+(defcustom ghostel-github-release-url
   "https://github.com/dakra/ghostel/releases"
-  "Base URL for ghostel GitHub releases.")
+  "Base URL for Ghostel GitHub releases.
+Customize this when downloading pre-built modules from a fork or mirror."
+  :type 'string)
 
 (defconst ghostel--minimum-module-version "0.13.0"
   "Minimum native module version required by this Elisp version.
@@ -423,22 +425,26 @@ Returns nil if the platform is not recognized."
     (when tag
       (format "ghostel-module-%s%s" tag module-file-suffix))))
 
-(defun ghostel--module-download-url ()
-  "Return the download URL for the current platform's pre-built module."
+(defun ghostel--module-download-url (&optional version)
+  "Return the download URL for the current platform's pre-built module.
+When VERSION is nil, use the latest release download URL."
   (let ((asset-name (ghostel--module-asset-name)))
     (when asset-name
-      (let ((version (ghostel--package-version)))
-        (if version
-            (format "%s/download/v%s/%s"
-                    ghostel-github-release-url version asset-name)
-          (format "%s/latest/download/%s"
-                  ghostel-github-release-url asset-name))))))
-
-(defun ghostel--download-module (dir)
+      (if version
+          (format "%s/download/v%s/%s"
+                  ghostel-github-release-url version asset-name)
+        (format "%s/latest/download/%s"
+                ghostel-github-release-url asset-name)))))
+
+(defun ghostel--download-module (dir &optional version latest-release)
   "Download a pre-built module into DIR.
+When VERSION is non-nil, download that release tag.
+When LATEST-RELEASE is non-nil, use the latest release asset URL.
 Returns non-nil on success."
   (condition-case err
-      (let ((url (ghostel--module-download-url)))
+      (let* ((requested-version (unless latest-release
+                                  (or version ghostel--minimum-module-version)))
+             (url (ghostel--module-download-url requested-version)))
         (when url
           (unless (string-prefix-p "https://" url)
             (error "Refusing non-HTTPS download URL: %s" url))
@@ -484,16 +490,28 @@ Behavior is controlled by `ghostel-module-auto-install'."
       ('compile  (ghostel--compile-module dir))
       (_         nil))))
 
+(defun ghostel--read-module-download-version ()
+  "Prompt for a release tag to download, or nil for the latest release."
+  (let ((version (read-string
+                  (format "Ghostel module version (>= %s, empty for latest): "
+                          ghostel--minimum-module-version))))
+    (unless (string= version "")
+      (when (version< version ghostel--minimum-module-version)
+        (user-error "Version %s is older than minimum supported version %s"
+                    version ghostel--minimum-module-version))
+      version)))
+
 (defun ghostel--ask-install-action (_dir)
   "Prompt the user to choose how to install the missing native module.
 Returns \\='download, \\='compile, or nil."
-  (let* ((url (or (ghostel--module-download-url) "GitHub releases"))
+  (let* ((url (or (ghostel--module-download-url ghostel--minimum-module-version)
+                  "GitHub releases"))
          (choice (read-char-choice
                   (format "Ghostel native module not found.
 
   [d] Download pre-built binary from:
       %s
-  [c] Compile from source (requires Zig)
+  [c] Compile from source via build.sh
   [s] Skip — install manually later
 
 Choice: " url)
@@ -503,19 +521,6 @@ Choice: " url)
       (?c 'compile)
       (?s nil))))
 
-(defun ghostel--package-version ()
-  "Return ghostel release version string, or nil.
-Reads the Version header from ghostel.el so the download URL
-matches the GitHub release tag even when MELPA rewrites the
-version to a date-based string."
-  (require 'lisp-mnt nil t)
-  (when (fboundp 'lm-header)
-    (let ((lib (or load-file-name (locate-library "ghostel.el" t))))
-      (when lib
-        (with-temp-buffer
-          (insert-file-contents lib nil 0 1024)
-          (lm-header "Version"))))))
-
 (defun ghostel--download-file (url dest)
   "Download URL to DEST.  Return non-nil on success."
   (condition-case nil
@@ -539,18 +544,23 @@ version to a date-based string."
                 (kill-buffer buf))))))
     (error nil)))
 
-(defun ghostel-download-module ()
-  "Interactively download the pre-built native module for this platform."
-  (interactive)
+(defun ghostel-download-module (&optional prompt-for-version)
+  "Interactively download the pre-built native module for this platform.
+With PROMPT-FOR-VERSION, prompt for a release tag to download.
+Leaving the prompt empty downloads the latest release."
+  (interactive "P")
   (let* ((dir (file-name-directory (or load-file-name
                                        (locate-library "ghostel")
                                        buffer-file-name)))
          (mod (expand-file-name
-               (concat "ghostel-module" module-file-suffix) dir)))
+               (concat "ghostel-module" module-file-suffix) dir))
+         (version (when prompt-for-version
+                    (ghostel--read-module-download-version)))
+         (latest-release (and prompt-for-version (null version))))
     (when (and (file-exists-p mod)
                (not (yes-or-no-p "Module already exists.  Re-download? ")))
       (user-error "Cancelled"))
-    (if (ghostel--download-module dir)
+    (if (ghostel--download-module dir version latest-release)
         (progn
           (module-load mod)
           (message "ghostel: module loaded successfully"))
@@ -601,7 +611,6 @@ DIR is the module directory."
                        (concat "Native module not found: " mod
                                "\nRun M-x ghostel-download-module or M-x ghostel-module-compile")))))
 
-
 ;;; Internal variables
 
 (defvar-local ghostel--term nil

test/ghostel-test.el

@@ -1970,14 +1970,123 @@ buffer and hand nil to the native module."
 ;; -----------------------------------------------------------------------
 
 ;; -----------------------------------------------------------------------
-;; Test: module version check
-;; -----------------------------------------------------------------------
-
-(ert-deftest ghostel-test-package-version ()
-  "Test that `ghostel--package-version' returns a version string."
-  (let ((ver (ghostel--package-version)))
-    (should (stringp ver))
-    (should (string-match-p "^[0-9]+\\.[0-9]+\\.[0-9]+" ver))))
+;; Test: module download version selection
+;; -----------------------------------------------------------------------
+
+(ert-deftest ghostel-test-module-download-url-uses-requested-version ()
+  "Requested download versions are decoupled from the package version."
+  (let ((ghostel-github-release-url "https://example.invalid/releases"))
+    (cl-letf (((symbol-function 'ghostel--module-asset-name)
+               (lambda () "ghostel-module-x86_64-linux.so")))
+      (should (equal "https://example.invalid/releases/download/v0.7.1/ghostel-module-x86_64-linux.so"
+                     (ghostel--module-download-url "0.7.1"))))))
+
+(ert-deftest ghostel-test-module-download-url-uses-latest-release ()
+  "A nil download version uses the latest release asset."
+  (let ((ghostel-github-release-url "https://example.invalid/releases"))
+    (cl-letf (((symbol-function 'ghostel--module-asset-name)
+               (lambda () "ghostel-module-x86_64-linux.so")))
+      (should (equal "https://example.invalid/releases/latest/download/ghostel-module-x86_64-linux.so"
+                     (ghostel--module-download-url nil))))))
+
+(ert-deftest ghostel-test-download-module-defaults-to-minimum-version ()
+  "Automatic downloads pin to the minimum supported native module version."
+  (let ((ghostel--minimum-module-version "0.7.1")
+        (captured-version :unset)
+        (download-dest nil))
+    (cl-letf (((symbol-function 'ghostel--module-download-url)
+               (lambda (&optional version)
+                 (setq captured-version version)
+                 "https://example.invalid/releases/download/v0.7.1/ghostel-module-x86_64-linux.so"))
+              ((symbol-function 'ghostel--download-file)
+               (lambda (_url dest)
+                 (setq download-dest dest)
+                 t))
+              ((symbol-function 'message)
+               (lambda (&rest _))))
+      (should (ghostel--download-module "C:/ghostel/"))
+      (should (equal "0.7.1" captured-version))
+      (should (equal (downcase (expand-file-name
+                                (concat "ghostel-module" module-file-suffix)
+                                "C:/ghostel/"))
+                     (downcase download-dest))))))
+
+(ert-deftest ghostel-test-download-module-prefix-uses-requested-version ()
+  "Prefix downloads pass the requested release version through unchanged."
+  (let ((ghostel--minimum-module-version "0.7.1")
+        (captured-version :unset)
+        (captured-latest nil)
+        (loaded-module nil))
+    (let ((comp-enable-subr-trampolines nil)
+          (native-comp-enable-subr-trampolines nil))
+      (cl-letf (((symbol-function 'locate-library)
+                 (lambda (_) "C:/ghostel/ghostel.el"))
+                ((symbol-function 'file-exists-p)
+                 (lambda (_) nil))
+                ((symbol-function 'read-string)
+                 (lambda (&rest _) "0.8.0"))
+                ((symbol-function 'ghostel--download-module)
+                 (lambda (_dir &optional version latest-release)
+                   (setq captured-version version
+                         captured-latest latest-release)
+                   t))
+                ((symbol-function 'module-load)
+                 (lambda (path)
+                   (setq loaded-module path)))
+                ((symbol-function 'message)
+                 (lambda (&rest _))))
+        (ghostel-download-module '(4))
+        (should (equal "0.8.0" captured-version))
+        (should-not captured-latest)
+        (should (equal (downcase (expand-file-name
+                                  (concat "ghostel-module" module-file-suffix)
+                                  "C:/ghostel/"))
+                       (downcase loaded-module)))))))
+
+(ert-deftest ghostel-test-download-module-prefix-empty-uses-latest ()
+  "Prefix download treats blank input as a request for the latest release."
+  (let ((captured-version :unset)
+        (captured-latest nil)
+        (loaded-module nil))
+    (let ((comp-enable-subr-trampolines nil)
+          (native-comp-enable-subr-trampolines nil))
+      (cl-letf (((symbol-function 'locate-library)
+                 (lambda (_) "C:/ghostel/ghostel.el"))
+                ((symbol-function 'file-exists-p)
+                 (lambda (_) nil))
+                ((symbol-function 'read-string)
+                 (lambda (&rest _) ""))
+                ((symbol-function 'ghostel--download-module)
+                 (lambda (_dir &optional version latest-release)
+                   (setq captured-version version
+                         captured-latest latest-release)
+                   t))
+                ((symbol-function 'module-load)
+                 (lambda (path)
+                   (setq loaded-module path)))
+                ((symbol-function 'message)
+                 (lambda (&rest _))))
+        (ghostel-download-module '(4))
+        (should (null captured-version))
+        (should captured-latest)
+        (should (equal (downcase (expand-file-name
+                                  (concat "ghostel-module" module-file-suffix)
+                                  "C:/ghostel/"))
+                       (downcase loaded-module)))))))
+
+(ert-deftest ghostel-test-download-module-prefix-rejects-too-old-version ()
+  "Prefix download rejects versions below the minimum supported version."
+  (let ((ghostel--minimum-module-version "0.7.1"))
+    (let ((comp-enable-subr-trampolines nil)
+          (native-comp-enable-subr-trampolines nil))
+      (cl-letf (((symbol-function 'locate-library)
+                 (lambda (_) "C:/ghostel/ghostel.el"))
+                ((symbol-function 'file-exists-p)
+                 (lambda (_) nil))
+                ((symbol-function 'read-string)
+                 (lambda (&rest _) "0.7.0")))
+        (should-error (ghostel-download-module '(4))
+                      :type 'user-error)))))
 
 (ert-deftest ghostel-test-compile-module-invokes-zig-build ()
   "Source compilation runs zig build directly."
@@ -2787,9 +2896,14 @@ while :; do sleep 0.1; done'\n")
     ghostel-test-project-universal-arg
     ghostel-test-copy-all
     ghostel-test-copy-mode-buffer-navigation
-    ghostel-test-package-version
     ghostel-test-compile-module-invokes-zig-build
     ghostel-test-module-compile-command-uses-zig-build
+    ghostel-test-module-download-url-uses-requested-version
+    ghostel-test-module-download-url-uses-latest-release
+    ghostel-test-download-module-defaults-to-minimum-version
+    ghostel-test-download-module-prefix-uses-requested-version
+    ghostel-test-download-module-prefix-empty-uses-latest
+    ghostel-test-download-module-prefix-rejects-too-old-version
     ghostel-test-module-version-match
     ghostel-test-module-version-mismatch
     ghostel-test-module-version-newer-than-minimum