[nongnu] elpa/emacsql cefe1ec014 121/427: Add emacsql-sqlite3-unavailable-p.

[ELPA Syncer]

branch: elpa/emacsql
commit cefe1ec01426231bdb79e154f5301f1500ed68b1
Author: Christopher Wellons <wellons@nullprogram.com>
Commit: Christopher Wellons <wellons@nullprogram.com>

    Add emacsql-sqlite3-unavailable-p.
---
 README.md        |  2 +-
 emacsql-tests.el |  1 +
 emacsql.el       | 18 ++++++++++++++++++
 3 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 320333fe43..9675a6fdca 100644
--- a/README.md
+++ b/README.md
@@ -14,7 +14,7 @@ Emacsql, including numbers, strings, symbols, lists, vectors, 
and
 closures. Emacsql has no concept of "TEXT" values; it's all just lisp
 objects.
 
-Requires Emacs 24 or later.
+Requires Emacs 24 or later and SQLite 3.7.15 or later.
 
 Due to [bad behavior from SQLite on Windows][stderr] Emacsql will
 *not* signal error messages for invalid statements on this platform.
diff --git a/emacsql-tests.el b/emacsql-tests.el
index 2138d3ec96..5744e3c3a2 100644
--- a/emacsql-tests.el
+++ b/emacsql-tests.el
@@ -75,6 +75,7 @@
                        "CREATE TEMPORARY TABLE IF NOT EXISTS x (y);"))
 
 (ert-deftest emacsql-system ()
+  (should-not (emacsql-sqlite3-unavailable-p))
   (emacsql-with-connection (db nil)
     (emacsql db [:create-table foo [x]])
     (should-error (emacsql db [:create-table foo [x]]))
diff --git a/emacsql.el b/emacsql.el
index 70cf4e673c..20b04eb632 100644
--- a/emacsql.el
+++ b/emacsql.el
@@ -99,6 +99,24 @@ This collection exists for cleanup purposes.")
              do (accept-process-output)))
   (emacsql--clear conn))
 
+(defun emacsql-sqlite3-unavailable-p ()
+  "Return a reason if the sqlite3 executable is not available.
+
+:no-executable -- cannot find the executable
+:cannot-execute -- cannot run the executable
+:old-version -- sqlite3 version is too old"
+  (let ((sqlite3 emacsql-sqlite3-executable))
+    (if (null (executable-find sqlite3))
+        :no-executable
+      (condition-case _
+          (with-temp-buffer
+            (call-process sqlite3 nil (current-buffer) nil "--version")
+            (let ((version (car (split-string (buffer-string)))))
+              (if (version< version "3.7.15")
+                  :old-version
+                nil)))
+        (error :cannot-execute)))))
+
 (cl-defun emacsql-connect (file &key log)
   "Open a connected to database stored in FILE.
 If FILE is nil use an in-memory database.