Make docker gitea/gitea:v1.15-dev etc refer to the latest build on that branch (#18551) (#18569) (#18575)

Backport #18551

One of the problems with our current docker tagging is that although we
have strict version tags, latest and dev we do not have a way for docker
users to track the current release branch. This PR simply suggests that
we use the 1.x-dev tag for these and we build and push these. This will
give users who want or need unreleased bug fixes the option of tracking
the pre-release version instead of simply jumping to dev.

However, there is a problem with #18551/#18569 whereby the manifest is
not properly uploading. Therefore this PR adds in some debug logging
in order to get this to debug things.

Signed-off-by: Andrew Thornton <art27@cantab.net>

.drone.yml

@@ -1041,6 +1041,7 @@ steps:
       auto_tag: false
       ignore_missing: true
       spec: docker/manifest.rootless.tmpl
+      dump: true
       password:
         from_secret: docker_password
       username:
@@ -1052,6 +1053,7 @@ steps:
       auto_tag: false
       ignore_missing: true
       spec: docker/manifest.tmpl
+      dump: true
       password:
         from_secret: docker_password
       username:
@@ -1060,6 +1062,7 @@ steps:
 trigger:
   ref:
   - refs/heads/main
+  - "refs/heads/release/v*"
   event:
     exclude:
     - cron

docker/manifest.rootless.tmpl

@@ -1,4 +1,9 @@
-image: gitea/gitea:{{#if build.tag}}{{trimPrefix "v" build.tag}}{{else}}dev{{/if}}-rootless
+# tag: {{build.tag}}
+# commit: {{build.commit}}
+# ref: {{build.ref}}
+# branch: {{build.branch}}
+#
+image: gitea/gitea:{{#if build.tag}}{{trimPrefix "v" build.tag}}{{else}}{{#equal build.ref "refs/heads/main"}}dev{{else}}{{trimPrefix "refs/heads/release/v" build.ref}}-dev{{/equal}}{{/if}}-rootless
 {{#if build.tags}}
 tags:
 {{#each build.tags}}
@@ -8,12 +13,12 @@ tags:
 {{/if}}
 manifests:
   -
-    image: gitea/gitea:{{#if build.tag}}{{trimPrefix "v" build.tag}}{{else}}dev{{/if}}-linux-amd64-rootless
+    image: gitea/gitea:{{#if build.tag}}{{trimPrefix "v" build.tag}}{{else}}{{#equal build.ref "refs/heads/main"}}dev{{else}}{{trimPrefix "refs/heads/release/v" build.ref}}-dev{{/equal}}{{/if}}-linux-amd64-rootless
     platform:
       architecture: amd64
       os: linux
   -
-    image: gitea/gitea:{{#if build.tag}}{{trimPrefix "v" build.tag}}{{else}}dev{{/if}}-linux-arm64-rootless
+    image: gitea/gitea:{{#if build.tag}}{{trimPrefix "v" build.tag}}{{else}}{{#equal build.ref "refs/heads/main"}}dev{{else}}{{trimPrefix "refs/heads/release/v" build.ref}}-dev{{/equal}}{{/if}}-linux-arm64-rootless
     platform:
       architecture: arm64
       os: linux

docker/manifest.tmpl

@@ -1,4 +1,9 @@
-image: gitea/gitea:{{#if build.tag}}{{trimPrefix "v" build.tag}}{{else}}dev{{/if}}
+# tag: {{build.tag}}
+# commit: {{build.commit}}
+# ref: {{build.ref}}
+# branch: {{build.branch}}
+#
+image: gitea/gitea:{{#if build.tag}}{{trimPrefix "v" build.tag}}{{else}}{{#equal build.ref "refs/heads/main"}}dev{{else}}{{trimPrefix "refs/heads/release/v" build.ref}}-dev{{/equal}}{{/if}}
 {{#if build.tags}}
 tags:
 {{#each build.tags}}
@@ -7,12 +12,12 @@ tags:
 {{/if}}
 manifests:
   -
-    image: gitea/gitea:{{#if build.tag}}{{trimPrefix "v" build.tag}}-{{else}}dev-{{/if}}linux-amd64
+    image: gitea/gitea:{{#if build.tag}}{{trimPrefix "v" build.tag}}{{else}}{{#equal build.ref "refs/heads/main"}}dev{{else}}{{trimPrefix "refs/heads/release/v" build.ref}}-dev{{/equal}}{{/if}}-linux-amd64
     platform:
       architecture: amd64
       os: linux
   -
-    image: gitea/gitea:{{#if build.tag}}{{trimPrefix "v" build.tag}}-{{else}}dev-{{/if}}linux-arm64
+    image: gitea/gitea:{{#if build.tag}}{{trimPrefix "v" build.tag}}{{else}}{{#equal build.ref "refs/heads/main"}}dev{{else}}{{trimPrefix "refs/heads/release/v" build.ref}}-dev{{/equal}}{{/if}}-linux-arm64
     platform:
       architecture: arm64
       os: linux