config: Allow expanding loaded configurations.

* gnu/gnunet/config/fs.scm
  (make-expanded-configuration): New procedure.
* doc/scheme-gnunet.tm (Loading configuration files):
  Document new procedure.
* tests/config-fs.scm
  (load-string->config/expanded, load-string->alist/expanded):
  New procedures.
  ("make-expanded-configuration, one variable"
  ("make-expanded-configuration, expand variable (via getenv)")
  ("make-expanded-configuration, expand variable (via getenv, fancyness)")
  ("make-expanded-configuration, expand variable (via PATHS)")
  ("make-expanded-configuration, expand variable (via PATHS + getenv)")
  ("make-expanded-configuration, loop detected"): New tests.

1 files changed, 69 insertions, 1 deletions

diff --git a/tests/config-fs.scm b/tests/config-fs.scm
index e457b0a..b194a6b 100644
--- a/tests/config-fs.scm
+++ b/tests/config-fs.scm
@@ -16,8 +16,12 @@
 ;;
 ;; SPDX-License-Identifier: AGPL3.0-or-later
 
-(import (gnu gnunet config fs)
+(import (gnu gnunet config db)
+        (gnu gnunet config expand)
+        (gnu gnunet config fs)
         (gnu gnunet config parser)
+        (rnrs exceptions)
+        (srfi srfi-1)
         (srfi srfi-64))
 (test-begin "config-fs")
 
@@ -145,4 +149,68 @@
   (load-string->alist/unexpanded
    "[section1]\nVAR = VALUE\n[section2]\nVAR2 = VALUE2"))
 
+(define (load-string->config/expanded text environment-variables)
+  (make-expanded-configuration
+   (lambda (set-value!)
+     (call-with-input-string text
+       (lambda (p)
+         (load-configuration/port! set-value! p))))
+   #:getenv
+   (alist->getenv environment-variables)))
+
+(define (load-string->alist/expanded text interested environment-variables)
+  (define config (load-string->config/expanded text environment-variables))
+  (filter-map (lambda (section+key)
+                `(,section+key
+                  . ,(guard (c ((undefined-key-error? c) 'undefined))
+                       (read-value identity config (car section+key)
+                                   (cdr section+key)))))
+              interested))
+
+(test-equal "make-expanded-configuration, one variable"
+  '((("sect" . "var") . "iable"))
+  (load-string->alist/expanded "[sect]\nvar=iable"
+                               '(("sect" . "var")) '()))
+
+;; Detected a missing 'list'
+(test-equal "make-expanded-configuration, expand variable (via getenv)"
+  '((("sect" . "var") . "iable"))
+  (load-string->alist/expanded "[sect]\nvar=i$a"
+                               '(("sect" . "var")) '(("a" . "able"))))
+
+
+(test-equal "make-expanded-configuration, expand variable (via getenv, fancyness)"
+  '((("sect" . "var") . "i}\\$able%f'"))
+  (load-string->alist/expanded "[sect]\nvar=i$a"
+                               '(("sect" . "var"))
+                               '(("a" . "}\\$able%f'"))))
+
+(test-equal "make-expanded-configuration, expand variable (via PATHS)"
+  '((("sect" . "var") . "iable")
+    (("PATHS" . "something") . "able"))
+  (load-string->alist/expanded
+   "[sect]\nvar=i$something\n[PATHS]\nsomething=able"
+   '(("sect" . "var")
+     ("PATHS" . "something"))
+   '()))
+
+;; Detects incorrect implementation of substring=? (string=? was used instead)
+(test-equal "make-expanded-configuration, expand variable (via PATHS + getenv)"
+  '((("sect" . "var") . "iable")
+    (("PATHS" . "something") . "able"))
+  (load-string->alist/expanded
+   "[sect]\nvar=i$something\n[PATHS]\nsomething=a$else"
+   '(("sect" . "var")
+     ("PATHS" . "something"))
+   '(("else" . "ble"))))
+
+;; Detect implementations of substring=? that always return #f.
+(test-equal "make-expanded-configuration, loop detected"
+  #t
+  (guard (c ((expansion-loop-error? c) #t))
+    (load-string->alist/expanded
+     "[sect]\nvar=i${something}\n[PATHS]\nsomething=d${something}"
+     '(("PATHS" . "something"))
+     '(("something" . "unused")))))
+
 (test-end "config-fs")