From 41c0156fe3acf5545d12ffd166c3e71a79efb0c2 Mon Sep 17 00:00:00 2001
From: Eli Barzilay <eli@barzilay.org>
Date: Tue, 9 Jul 2013 20:45:41 -0400
Subject: [PATCH] Delay running git, to avoid a premature warning about
 $GIT_DIR.

---
 pkgs/plt-services/meta/web/download/data.rkt  | 19 +++++++++++----
 .../meta/web/download/release-info.rkt        | 23 +++++++++++--------
 .../meta/web/download/version.rkt             |  4 ++--
 3 files changed, 29 insertions(+), 17 deletions(-)

diff --git a/pkgs/plt-services/meta/web/download/data.rkt b/pkgs/plt-services/meta/web/download/data.rkt
index 62470162ba..f21ee91a88 100644
--- a/pkgs/plt-services/meta/web/download/data.rkt
+++ b/pkgs/plt-services/meta/web/download/data.rkt
@@ -111,7 +111,7 @@
          set-announcements-file!)
 
 (require racket/list racket/file version/utils racket/runtime-path
-         "release-info.rkt")
+         racket/promise "release-info.rkt")
 
 ;; ----------------------------------------------------------------------------
 ;; Mirror information
@@ -204,8 +204,17 @@
             [else (loop (cdr l) (add1 n))])))
   (λ (x y) (< (num-of x) (num-of y))))
 
+;; use this to avoid parsing the installers until generation starts
+(define-syntax-rule (define-lazy name expr)
+  (begin (define p (lazy expr))
+         (define-syntax name
+           (syntax-id-rules (set!)
+             [(set! _ x)      (error 'name "unmodifiable binding")]
+             [(_ x (... ...)) ((force p) x (... ...))]
+             [_               (force p)]))))
+
 ;; sorted by version (newest first), and then by -installer-orders-
-(define all-installers
+(define-lazy all-installers
   (sort
    (call-with-input-file installers-data parse-installers)
    (let ([fns `([,(λ (i)
@@ -220,11 +229,11 @@
            (let* ([get (caar fns)] [<? (cdar fns)] [x1 (get i1)] [x2 (get i2)])
              (or (<? x1 x2) (and (equal? x1 x2) (loop (cdr fns)))))))))))
 
-(define all-releases ; still sorted from newest to oldest
+(define-lazy all-releases ; still sorted from newest to oldest
   (remove-duplicates (map installer-release all-installers)))
-(define all-packages ; also sorted
+(define-lazy all-packages ; also sorted
   (remove-duplicates (map installer-package all-installers)))
-(define current-release (car all-releases))
+(define-lazy current-release (car all-releases))
 
 (define package->name
   (let ([t (make-hasheq)])
diff --git a/pkgs/plt-services/meta/web/download/release-info.rkt b/pkgs/plt-services/meta/web/download/release-info.rkt
index b9fb918342..f8c5ad001c 100644
--- a/pkgs/plt-services/meta/web/download/release-info.rkt
+++ b/pkgs/plt-services/meta/web/download/release-info.rkt
@@ -1,8 +1,9 @@
 #lang racket/base
 
-(require racket/system racket/port racket/match racket/runtime-path)
+(require racket/system racket/port racket/match racket/runtime-path
+         racket/promise)
 
-(define-runtime-path THIS-GIT "../../../../.git")
+(define-runtime-path THIS-GIT "../../../../../.git")
 
 (define (warn fmt . xs)
   (eprintf "Warning: ~a\a\n" (apply format fmt xs))
@@ -10,14 +11,15 @@
   (sleep 1)
   #f)
 
-(define git
-  (let* ([exe (or (find-executable-path "git")
-                  (warn "no `git' executable => no release info"))]
-         [try (λ (dir) (and dir (directory-exists? dir) dir))]
-         [dir (and exe (or (ormap try (list (getenv "GIT_DIR") THIS-GIT))
-                           (warn "no git dir found => no release info\n  (~a)"
-                                 "set $GIT_DIR to a racket repo .git dir")))]
-         [nowhere (open-output-nowhere)])
+(define git*
+  (lazy
+    (define exe (or (find-executable-path "git")
+                    (warn "no `git' executable => no release info")))
+    (define (try dir) (and dir (directory-exists? dir) dir))
+    (define dir (and exe (or (ormap try (list (getenv "GIT_DIR") THIS-GIT))
+                             (warn "no git dir found => no release info\n  (~a)"
+                                   "set $GIT_DIR to a racket repo .git dir"))))
+    (define nowhere (open-output-nowhere))
     (and dir (λ args (define o (open-output-string))
                      (parameterize ([current-directory dir]
                                     [current-output-port o]
@@ -27,6 +29,7 @@
 
 (provide get-version-tag-info)
 (define (get-version-tag-info version)
+  (define git (force git*))
   (let/ec return
     (unless git (return #f))
     (define (bad . args) (apply warn args) (return #f))
diff --git a/pkgs/plt-services/meta/web/download/version.rkt b/pkgs/plt-services/meta/web/download/version.rkt
index 6f2f144449..88e63e95df 100644
--- a/pkgs/plt-services/meta/web/download/version.rkt
+++ b/pkgs/plt-services/meta/web/download/version.rkt
@@ -3,5 +3,5 @@
 (require "resources.rkt" "data.rkt")
 
 (define version.txt
-  (let ([v (release-version current-release)])
-    (plain (format "~s" `((recent ,v) (stable ,v))))))
+  (plain (lazy (let ([v (release-version current-release)])
+                 (format "~s" `((recent ,v) (stable ,v)))))))