From 788e507d494e684f6ded6e3979761aa95aea45f3 Mon Sep 17 00:00:00 2001
From: Henrik Lissner <git@henrik.io>
Date: Wed, 22 Feb 2023 00:44:38 -0500
Subject: [PATCH] fix(java): errors in company-yasnippet snippet previews

Because company-yasnippet expands each snippet to produce a preview in a
temporary (and fundamental-mode) buffer, java-current-class and
java-current-package throws errors, so I've added a special case to
return a placeholder if expanded in a temporary buffer.
---
 modules/lang/java/autoload/java.el | 37 ++++++++++++++++++------------
 1 file changed, 22 insertions(+), 15 deletions(-)

diff --git a/modules/lang/java/autoload/java.el b/modules/lang/java/autoload/java.el
index 87e7d1d35..ed0ebddcd 100644
--- a/modules/lang/java/autoload/java.el
+++ b/modules/lang/java/autoload/java.el
@@ -42,13 +42,18 @@ Is converted to: net.lissner.game
 It does this by ignoring everything before the nearest package root (see
 `+java-project-package-roots' to control what this function considers a package
 root)."
-  (unless (eq major-mode 'java-mode)
-    (user-error "Not in a java-mode buffer"))
-  (let* ((project-root (file-truename (doom-project-root)))
-         (file-path (file-name-sans-extension
-                     (file-truename (or buffer-file-name
-                                        default-directory))))
-         (src-root (cl-loop for root in +java-project-package-roots
+  (cond ((doom-special-buffer-p (current-buffer))
+         "{PackageName}")
+        ((not (eq major-mode 'java-mode))
+         (user-error "Not in java-mode"))
+        ((when-let (project-root (doom-project-root))
+           (let* ((project-root (file-truename project-root))
+                  (file-path
+                   (file-name-sans-extension
+                    (file-truename (or buffer-file-name
+                                       default-directory))))
+                  (src-root
+                   (cl-loop for root in +java-project-package-roots
                             if (and (stringp root)
                                     (locate-dominating-file file-path root))
                             return (file-name-directory (file-relative-name file-path (expand-file-name root it)))
@@ -59,18 +64,20 @@ root)."
                                       (when fixed-parts
                                         (string-join fixed-parts "/"))))
                             return it)))
-    (when src-root
-      (string-remove-suffix "." (replace-regexp-in-string "/" "." src-root)))))
+             (when src-root
+               (string-remove-suffix "." (replace-regexp-in-string "/" "." src-root))))))
+        ((user-error "Can't deduce package name"))))
 
 ;;;###autoload
 (defun +java-current-class ()
   "Get the class name for the current file."
-  (unless (eq major-mode 'java-mode)
-    (user-error "Not in a java-mode buffer"))
-  (unless buffer-file-name
-    (user-error "This buffer has no filepath; cannot guess its class name"))
-  (or (file-name-sans-extension (file-name-base (buffer-file-name)))
-      "ClassName"))
+  (cond ((doom-special-buffer-p (current-buffer))
+         "{ClassName}")
+        ((not (eq major-mode 'java-mode))
+         (user-error "Not in java-mode"))
+        (buffer-file-name
+         (file-name-sans-extension (file-name-base (buffer-file-name))))
+        ((user-error "Can't deduce the class name"))))
 
 ;;;###autoload
 (defun +java/open-groovy-repl ()