Add lint-warning-count-by-lint-checker-for-revision

To return counts of lint warnings, grouped by lint checker for a specific
revision.

guix-data-service/model/lint-checker.scm

@@ -1,8 +1,10 @@
 (define-module (guix-data-service model lint-checker)
   #:use-module (srfi srfi-1)
   #:use-module (ice-9 match)
+  #:use-module (squee)
   #:use-module (guix-data-service model utils)
-  #:export (lint-checkers->lint-checker-ids))
+  #:export (lint-checkers->lint-checker-ids
+            lint-warning-count-by-lint-checker-for-revision))
 
 (define (lint-checkers->lint-checker-ids conn lint-checkers-data)
   (insert-missing-data-and-return-all-ids
@@ -13,3 +15,25 @@
      (description       . ,quote-string)
      (network_dependent . ,value->sql-boolean))
    lint-checkers-data))
+
+(define (lint-warning-count-by-lint-checker-for-revision conn commit-hash)
+  (define query
+    "
+SELECT lint_checkers.name, lint_checkers.description,
+       lint_checkers.network_dependent, revision_data.count
+FROM lint_checkers
+INNER JOIN (
+  SELECT lint_checker_id, COUNT(*)
+  FROM lint_warnings
+  WHERE id IN (
+    SELECT lint_warning_id
+    FROM guix_revision_lint_warnings
+    INNER JOIN guix_revisions
+    ON guix_revision_lint_warnings.guix_revision_id = guix_revisions.id
+    WHERE commit = $1
+  )
+  GROUP BY lint_checker_id
+) AS revision_data ON lint_checkers.id = revision_data.lint_checker_id
+ORDER BY count DESC")
+
+  (exec-query conn query (list commit-hash)))