Statically link postgres calls for tree shaking

clj/jdbc/core.clj

@@ -16,7 +16,8 @@
         (jdbc/insert! conn :p {:name \"ada\"})
         (jdbc/fetch conn [\"select * from p where name = ?\" \"ada\"]))"
   (:require [clojure.string :as str]
-            [db.sqlite :as sqlite]))
+            [db.sqlite :as sqlite]
+            [db.pg :as pg]))
 
 ;;; dbspec
 
@@ -48,10 +49,6 @@
 
 ;;; connection
 
-;; the postgres driver is reached through pgfn, defined with the other pg helpers
-;; below; connection calls it for the :postgresql branch.
-(declare pgfn)
-
 (defn connection
   "Open a connection. spec is a uri string (\"sqlite:path\", a bare sqlite
   path, or \"postgres://user:pass@host:port/db\") or a dbspec map with
@@ -69,15 +66,14 @@
          :rollback (atom false)
          :close    (fn [] (sqlite/close h))})
       "postgresql"
-      ;; db.pg (and libpq) load lazily — only when a postgres connection is made,
-      ;; so a sqlite-only app never needs libpq present.
-      (do (require '[db.pg])
-          (let [h ((pgfn "connect") (pg-uri spec))]
-            {:vendor   :postgresql
-             :handle   h
-             :depth    (atom 0)
-             :rollback (atom false)
-             :close    (fn [] ((pgfn "close") h))})))))
+      ;; db.pg is statically required so AOT builds include the PostgreSQL
+      ;; implementation. Its FFI bindings resolve libpq symbols lazily on first use.
+      (let [h (pg/connect (pg-uri spec))]
+        {:vendor   :postgresql
+         :handle   h
+         :depth    (atom 0)
+         :rollback (atom false)
+         :close    (fn [] (pg/close h))}))))
 
 ;;; queries
 
@@ -212,12 +208,8 @@
 (defn- sqlite-eval [conn sql params]
   (sqlite/query (:handle conn) sql params))
 
-;; db.pg is required lazily (only for a postgres connection), so resolve its fns
-;; at runtime — a compile-time db.pg/foo reference would be read as a host class.
-(defn- pgfn [n] (deref (resolve (symbol "db.pg" n))))
-
 (defn- pg-eval [conn sql params]
-  ((pgfn "exec") (:handle conn) (pg-placeholders sql) params))
+  (pg/exec (:handle conn) (pg-placeholders sql) params))
 
 (defn fetch
   "Run a query (string or sqlvec), return a vector of keyword-keyed row maps."
@@ -226,7 +218,7 @@
    (let [[sql params] (sqlvec q)
          rows (case (:vendor conn)
                 :sqlite     (sqlite-eval conn sql params)
-                :postgresql ((pgfn "all") (:handle conn) (pg-placeholders sql) params))]
+                :postgresql (pg/all (:handle conn) (pg-placeholders sql) params))]
      (if-let [n (:max-rows opts)] (vec (take n rows)) rows))))
 
 (defn fetch-one
@@ -250,7 +242,7 @@
   [conn]
   (case (:vendor conn)
     :sqlite     (sqlite/last-insert-rowid (:handle conn))
-    :postgresql (:id (first ((pgfn "all") (:handle conn) "select lastval() as id" [])))))
+    :postgresql (:id (first (pg/all (:handle conn) "select lastval() as id" [])))))
 
 ;;; insert! / update! / delete! — the clojure.jdbc convenience surface