Add antsibull_preserve_deps option for the release role.

changelogs/fragments/599-prepare-preserve.yml

@@ -2,5 +2,6 @@ minor_changes:
   - "Add option ``--preserve-deps`` to the ``prepare`` subcommand that allows to preserve the
      dependencies if a ``.deps`` file for that version already exists. The versions from that
      ``.deps`` file are validated against the build requirements and constraints, and the
-     remainder of the release preparation process remains unchanged
+     remainder of the release preparation process remains unchanged. The release role allows
+     to pass this flag when ``antsibull_preserve_deps=true``
      (https://github.com/ansible-community/antsibull/pull/599)."

roles/build-release/defaults/main.yaml

@@ -41,6 +41,9 @@ antsibull_ansible_venv: "{{ antsibull_sdist_dir }}/venv"
 # Whether or not to start from scratch with a new venv if one exists
 antsibull_venv_cleanup: true
 
+# Whether to preserve existing .deps files during the prepare step
+antsibull_preserve_deps: false
+
 
 #####
 # These variables relate to verifying that collections properly tag their

roles/build-release/meta/argument_specs.yml

@@ -126,3 +126,11 @@ argument_specs:
           - Defaults to 0 (all available CPUs)
         type: int
         default: 0
+
+      antsibull_preserve_deps:
+        description:
+          - If set to V(true), will preserve existing C(.deps) files during the preparation
+            process and validate their contents against the build requirements and constraints.
+        type: bool
+        default: false
+        version_added: 0.62.0

roles/build-release/tasks/build.yaml

@@ -50,6 +50,7 @@
       --data-dir {{ antsibull_data_dir }}
       {{ _feature_freeze | default('') }}
       {{ '--tags-file' if antsibull_tags_validate else '' }}
+      {{ '--preserve-deps' if antsibull_preserve_deps else '' }}
   # Minimal failure tolerance to galaxy collection download errors
   retries: 3
   delay: 5