Improve self-upgrading.

There's no reason not to parse again the command line with the newly
loaded code actually, so be sure to do the self-upgrade dance first
thing and recurse to the pgloader::main function (with a guard).

README.md

@@ -74,13 +74,19 @@ If you want to test the current repository version (or any checkout really),
 it's possible to clone the sources then load them with an older pgloader
 release:
 
-    $ git clone https://github.com/dimitri/pgloader.git /tmp/pgloader
-    $ /usr/bin/pgloader --self-upgrade /tmp/pgloader myfile.load
+    $ /usr/bin/pgloader --version
+    pgloader version "3.0.99"
+    compiled with SBCL 1.1.17
     
-Here, the code from the *git clone* will be used at run-time. Of course,
-code that has changed before the self-upgrade mechanism is executed will
-have no change to get run again. That only includes command line options
-processing, though.
+    $ git clone https://github.com/dimitri/pgloader.git /tmp/pgloader
+    $ /usr/bin/pgloader --self-upgrade /tmp/pgloader --version
+    Self-upgrading from sources at "/Users/dim/dev/pgloader/"
+    pgloader version "3.0.fecae2c"
+    compiled with SBCL 1.1.17
+
+Here, the code from the *git clone* will be used at run-time. Self-upgrade
+is done first, then the main program entry point is called again with the
+new coded loaded in.
 
 ## The pgloader.lisp script
 

src/main.lisp

@@ -82,6 +82,9 @@
   (command-line-arguments:show-option-help *opt-spec*)
   (when quit (uiop:quit)))
 
+(defvar *self-upgraded-already* nil
+  "Keep track if we did reload our own source code already.")
+
 (defun self-upgrade (namestring)
   "Load pgloader sources at PATH-TO-PGLOADER-SOURCES."
   (let ((pgloader-pathname (uiop:directory-exists-p
@@ -97,7 +100,8 @@
                                                 asdf:*central-registry*)))
             (format t "Self-upgrading from sources at ~s~%"
                     (uiop:native-namestring pgloader-pathname))
-            (asdf:load-system :pgloader)))
+            (with-output-to-string (*standard-output*)
+              (asdf:operate 'asdf:load-op :pgloader :verbose nil))))
       (condition (c)
         (format t "Fatal: ~a~%" c)))))
 
@@ -118,6 +122,13 @@
 				root-dir self-upgrade)
 	  options
 
+        ;; First thing: Self Upgrade?
+        (when self-upgrade
+          (unless *self-upgraded-already*
+            (self-upgrade self-upgrade)
+            (let ((*self-upgraded-already* t))
+              (main argv))))
+
 	;; First care about the root directory where pgloader is supposed to
 	;; output its data logs and reject files
         (let ((root-dir-truename (probe-file root-dir)))
@@ -159,10 +170,6 @@
 	       (format t "~%~%"))
 	  (uiop:quit))
 
-        ;; Self Upgrade?
-        (when self-upgrade
-          (self-upgrade self-upgrade))
-
 	(when load
 	  (loop for filename in load
 	     do (load (compile-file filename :verbose nil :print nil))))