[bug#69827] [PATCH 3/3] import/go: Add diagnostics.

[Christina O'Donnell <cdo@mutix.org>]

guix/import/go.scm (go-module-available-versions): Add warning when fetching
a list of versions from the proxy fails and raise exception when no version
can be found at all.
(module-path->repository-root): Warn when all attempts to find the repository
root have failed.
(fetch-module-meta-data): Raise exception when no meta element could be found.
(go-module->guix-package): Catch general exceptions and warn that the package
could not be imported.

Change-Id: I6dcdccc71f54bfec7110f6bfc5aeb8855502d1e3
---
 guix/import/go.scm | 56 ++++++++++++++++++++++++++++++++++++----------
 1 file changed, 44 insertions(+), 12 deletions(-)

diff --git a/guix/import/go.scm b/guix/import/go.scm
index 8276797d9a..5dd5b3d221 100644
--- a/guix/import/go.scm
+++ b/guix/import/go.scm
@@ -140,10 +140,15 @@ (define* (go-module-available-versions goproxy name)
          (versions (remove string-null? (string-split body #\newline))))
     (if (null? versions)
         (begin
+          (warning (G_ "Empty list of versions on proxy ~a for package '~a'. Using latest.~%")
+                   goproxy name)
           ;; If we haven't recieved any versions, look in the version-info json
           ;; object and return a one-element list if found.
           (or (and=> (assoc-ref (go-module-version-info goproxy name) "Version")
-                     list))))
+                     list)
+              (raise (make-compound-condition
+                      (formatted-message (G_ "No versions available for '~a' on proxy ~a.")
+                                         name goproxy))))))
         versions))
 
 (define (go-package-licenses name)
@@ -467,7 +472,10 @@ (define (module-path->repository-root module-path version-info)
                                                (+ 1 (string-length subdir)))
                             #f)))))
       (vcs-qualified-module-path->root-repo-url module-path)
-      module-path))
+      (begin
+        (warning (G_ "Unable to determine repository root of '~a'. Guessing '~a'.~%")
+                 module-path module-path)
+        module-path)))
 
 (define* (go-module->guix-package-name module-path #:optional version)
   "Converts a module's path to the canonical Guix format for Go packages.
@@ -512,14 +520,19 @@ (define (fetch-module-meta-data module-path)
          (select (sxpath `(// (meta (@ (equal? (name "go-import"))))
                               // content))))
     (match (select (html->sxml meta-data #:strict? #t))
-      (() #f)                           ;nothing selected
+      (() (raise (make-compound-condition
+                  (formatted-message (G_ "no <meta/> element in result when accessing module path '~a' using go-get")
+                                     module-path))))
       ((('content content-text) ..1)
        (or
         (find (lambda (meta)
                 (string-prefix? (module-meta-import-prefix meta) module-path))
               (map go-import->module-meta content-text))
         ;; Fallback to the first meta if no import prefixes match.
-        (go-import->module-meta (first content-text)))))))
+        (go-import->module-meta (first content-text))
+        (raise (make-compound-condition
+                (formatted-message (G_ "unable to parse <meta/> when accessing module path '~a' using go-get")
+                                   module-path))))))))
 
 (define (module-meta-data-repo-url meta-data goproxy)
   "Return the URL where the fetcher which will be used can download the
@@ -716,16 +729,35 @@ (define go-module->guix-package*
     ;; consistently.
     (setvbuf (current-error-port) 'none)
     (let ((package-name (match args ((name _ ...) name))))
-      (guard (c ((http-get-error? c)
-                 (warning (G_ "Failed to import package ~s.
+      (begin
+        (info (G_ "Importing package ~s...~%") package-name)
+        (guard (c ((http-get-error? c)
+                        (warning (G_ "Failed to import package ~s.
 reason: ~s could not be fetched: HTTP error ~a (~s).
 This package and its dependencies won't be imported.~%")
-                          package-name
-                          (uri->string (http-get-error-uri c))
-                          (http-get-error-code c)
-                          (http-get-error-reason c))
-                 (values #f '())))
-        (apply go-module->guix-package args)))))
+                                 package-name
+                                 (uri->string (http-get-error-uri c))
+                                 (http-get-error-code c)
+                                 (http-get-error-reason c))
+
+                        (values #f '()))
+                  ((formatted-message? c)
+                   (warning (G_ "Failed to import package ~s.
+reason: ~a
+This package and its dependencies won't be imported.~%")
+                            package-name
+                            (apply format #f
+                                   (formatted-message-string c)
+                                   (formatted-message-arguments c)))
+                   (values #f '()))
+                  ((git-error? c)
+                   (warning (G_ "Failed to import package ~s.
+reason: ~a
+This package and its dependencies won't be imported.~%")
+                            package-name
+                            (git-error-message c))
+                   (values #f '())))
+               (apply go-module->guix-package args))))))
 
 (define* (go-module-recursive-import package-name
                                      #:key (goproxy "https://proxy.golang.org")
-- 
2.41.0