Merge branch 'feature/no-hypen-at-end-of-commit-ref-slug' into 'master'

no trailing / leading hyphens in CI_COMMIT_REF_SLUG.

Closes #32035

See merge request !11218

app/models/ci/build.rb

@@ -176,9 +176,12 @@ module Ci
     #   * Lowercased
     #   * Anything not matching [a-z0-9-] is replaced with a -
     #   * Maximum length is 63 bytes
+    #   * First/Last Character is not a hyphen
     def ref_slug
-      slugified = ref.to_s.downcase
-      slugified.gsub(/[^a-z0-9]/, '-')[0..62]
+      ref.to_s
+          .downcase
+          .gsub(/[^a-z0-9]/, '-')[0..62]
+          .gsub(/(\A-+|-+\z)/, '')
     end
 
     # Variables whose value does not depend on environment

changelogs/unreleased/feature-no-hypen-at-end-of-commit-ref-slug.yml

+---
+title: Omit trailing / leading hyphens in CI_COMMIT_REF_SLUG variable to make it usable as a hostname
+merge_request: 11218
+author: Stefan Hanreich

doc/ci/variables/README.md

@@ -37,7 +37,7 @@ future GitLab releases.**
 |-------------------------------- |--------|--------|-------------|
 | **CI**                          | all    | 0.4    | Mark that job is executed in CI environment |
 | **CI_COMMIT_REF_NAME**          | 9.0    | all    | The branch or tag name for which project is built |
-| **CI_COMMIT_REF_SLUG**          | 9.0    | all    | `$CI_COMMIT_REF_NAME` lowercased, shortened to 63 bytes, and with everything except `0-9` and `a-z` replaced with `-`. Use in URLs and domain names. |
+| **CI_COMMIT_REF_SLUG**          | 9.0    | all    | `$CI_COMMIT_REF_NAME` lowercased, shortened to 63 bytes, and with everything except `0-9` and `a-z` replaced with `-`. No leading / trailing `-`. Use in URLs, host names and domain names. |
 | **CI_COMMIT_SHA**               | 9.0    | all    | The commit revision for which project is built |
 | **CI_COMMIT_TAG**               | 9.0    | 0.5    | The commit tag name. Present only when building tags. |
 | **CI_DEBUG_TRACE**              | all    | 1.7    | Whether [debug tracing](#debug-tracing) is enabled |

spec/models/ci/build_spec.rb

@@ -1004,7 +1004,11 @@ describe Ci::Build, :models do
       'fix-1-foo'             => 'fix-1-foo',
       'a' * 63                => 'a' * 63,
       'a' * 64                => 'a' * 63,
-      'FOO'       => 'foo'
+      'FOO'                   => 'foo',
+      '-' + 'a' * 61 + '-'    => 'a' * 61,
+      '-' + 'a' * 62 + '-'    => 'a' * 62,
+      '-' + 'a' * 63 + '-'    => 'a' * 62,
+      'a' * 62 + ' '          => 'a' * 62
     }.each do |ref, slug|
       it "transforms #{ref} to #{slug}" do
         build.ref = ref