State explicitly where we take the tarball URL (#799)

State explicitly where we take the tarball URL

Reviewed-by: Laura Barcziová
Reviewed-by: Nikola Forró

docs/configuration/index.md

@@ -117,6 +117,17 @@ Previously known as `upstream_project_name`, which has been deprecated since Pac
 (*string*) URL of the upstream git project (e.g.
 `https://github.com/packit/packit`).
 
+:::info
+
+Do not confuse this with the URL of upstream tarball. In case of
+[`propose_downstream`](/docs/configuration/upstream/propose_downstream),
+[`pull_from_upstream`](/docs/configuration/downstream/pull_from_upstream),
+[`koji_build`](configuration/downstream/koji_build) and
+[`bodhi_update`](configuration/downstream/bodhi_update) jobs,
+upstream tarball URL is taken from spec file or from [sources](#sources).
+
+:::
+
 #### create_pr (only in CLI)
 
 (*bool*) When doing a new update in Fedora dist-git, should packit create a

docs/fedora-releases-guide.md

@@ -225,6 +225,7 @@ get dist-git pull requests with it automatically. If you want to restrict what r
 you can utilise the configuration options [`upstream_tag_include`](/docs/configuration/#upstream_tag_include) and
 [`upstream_tag_exclude`](/docs/configuration/#upstream_tag_exclude).
 
+It is necessary to set the [`upstream_project_url`](/docs/configuration/#upstream_project_url) (upstream project Git repository URL) configuration option. However, upstream tarball URL is taken from the spec file or from [`sources`](/docs/configuration/#sources) (see below).
 For customization of the job, you may need to define additional configuration options, most commonly:
 - If the version from release monitoring and Git tag differ, 
 you should specify the [`upstream_tag_template`](/docs/configuration/#upstream_tag_template).