fix: snap build (main branch) (#37685)

1. make "pull" and "build" testable and debuggable
2. add more comments for how the build works
3. separate 1.26 and main build tags
4. fix incorrect tag describe (the current `snap info gitea` outputs
version 1.22)

Legacy logic is kept as is although some of them don't seem good (e.g.:
snap version grep, tag finding, etc)

---------

Signed-off-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

snap/part-gitea-build.sh

@@ -0,0 +1,21 @@
+#!/bin/sh
+set -e
+
+if [ ! -f go.mod -o ! -d snap ]; then
+  echo "This script should be run from the root of the gitea repository"
+  exit 1
+fi
+
+if [ -z "$SNAPCRAFT_PART_INSTALL" ]; then
+  SNAPCRAFT_PART_INSTALL="./dist/snap"
+  echo "* using mock install path: $SNAPCRAFT_PART_INSTALL"
+fi
+
+command -v pnpm >/dev/null 2>&1 || npm install -g pnpm
+
+# build tags for 1.26: "bindata sqlite sqlite_unlock_notify pam cert"
+# for 1.27: sqlite is not needed, "cert" seems doing nothing
+TAGS="bindata pam" make build
+
+install -D gitea "${SNAPCRAFT_PART_INSTALL}/gitea"
+cp -r options "${SNAPCRAFT_PART_INSTALL}/"

snap/part-gitea-pull.sh

@@ -0,0 +1,62 @@
+#!/bin/sh
+set -e
+
+if [ ! -f go.mod -o ! -d snap ]; then
+  echo "This script should be run from the root of the gitea repository"
+  exit 1
+fi
+
+if [ -z "$SNAPCRAFT_PROJECT_NAME" ]; then
+  echo "No snapcraft build env, continue with mocking ...."
+  craftctl() { echo "* mocking craftctl: $*"; }
+  snap() { echo "* mocking snap: $*"; }
+else
+  echo "Add working directory to git safe.directory ..."
+  git config --global --add safe.directory "$PWD"
+fi
+
+# How it works:
+# * snapcraft.io checks out the default branch (e.g.: main during 1.27 dev period)
+# * "override-pull" step gets the latest tag by date (e.g.: v1.26.1)
+# * use "snap info gitea" to get the latest released tag
+#   * if the latest tag is not released to stable, checkout that tag and build it for "stable"
+#   * otherwise, build the main branch for "devel"
+# * "override-build" step uses build script from the checked out commit to build
+# This approach highly depends on the "main" branch's push.
+
+# To debug the logic:
+# * last_committed_tag=v1.26.1 last_released_tag=v1.26.0 ./snap/part-gitea-pull.sh
+#   it will checkout tag v1.26.1, and build that for "stable"
+# * last_committed_tag=v1.26.1 last_released_tag=v1.26.1 recent_tag=v1.27.0-dev-205 ./snap/part-gitea-pull.sh
+#   it will still use the current branch, and build it for "devel"
+
+[ -z "$last_committed_tag" ] && last_committed_tag="$(git for-each-ref --sort=taggerdate --format '%(tag)' refs/tags | tail -n 1)"
+[ -z "$last_released_tag" ] && last_released_tag="$(snap info gitea | awk '$1 == "latest/candidate:" { print $2 }')"
+
+if [ "${last_committed_tag}" != "${last_released_tag}" ]; then
+  # if the latest tag has not been released to stable, build that tag instead of default branch.
+  echo "Build last committed tag ${last_committed_tag} for new release, fetching and checking out ..."
+  git fetch --quiet
+  git checkout --quiet "${last_committed_tag}"
+  # HINT: after this, the "build" step will use that commit's "part-gitea-build.sh", but not this one's
+else
+  echo "Build current branch $(git branch --show-current) @ $(git rev-parse HEAD)"
+fi
+
+# possible tag names:
+# * v1.27.0-dev-205-gce089f498b
+# * v1.26.1
+# * v1.22.0-rc1-2816-gce089f498b
+# then normalize it to semver format: v1.2.3+dev.205.gce089f498b
+[ -z "$recent_tag" ] && recent_tag="$(git describe --always --tags)"
+echo "Use recent tag $recent_tag to determine version and grade"
+
+version_main="$(echo "$recent_tag" | cut -d'-' -f1)"
+version_ext="$(echo "$recent_tag" | cut -d'-' -s -f2- | sed -e 'y/-/./')"
+[ -n "$version_ext" ] && grade=devel || grade=stable
+
+version="${version_main}"
+[ -n "$version_ext" ] && version="${version}+${version_ext}"
+
+craftctl set version="$version"
+craftctl set grade="$grade"

snap/snapcraft.yaml

@@ -2,9 +2,9 @@ name: gitea
 summary: Gitea - A painless self-hosted Git service
 description: |
   The goal of this project is to make the easiest, fastest, and most painless
-  way of setting up a self-hosted Git service. With Go, this can be done with
-  an independent binary distribution across ALL platforms that Go supports,
-  including Linux, Mac OS X, Windows and ARM.
+  way of setting up a self-hosted Git service with GitHub-like experiences,
+  including issue tracking, code review, project management, wikis, package registry,
+  Gitea Actions and more.
 
 icon: public/assets/img/logo.png
 confinement: strict
@@ -53,31 +53,8 @@ parts:
     build-snaps: [ go/1.26/stable, node/24/stable ]
     build-environment:
       - LDFLAGS: ""
-    override-pull: |
-      craftctl default
-
-      git config --global --add safe.directory /root/parts/gitea/src
-      last_committed_tag="$(git for-each-ref --sort=taggerdate --format '%(tag)' refs/tags | tail -n 1)"
-      last_released_tag="$(snap info gitea | awk '$1 == "latest/candidate:" { print $2 }')"
-      # If the latest tag from the upstream project has not been released to
-      # stable, build that tag instead of master.
-      if [ "${last_committed_tag}" != "${last_released_tag}" ]; then
-        git fetch
-        git checkout "${last_committed_tag}"
-      fi
-
-      version="$(git describe --always | sed -e 's/-/+git/;y/-/./')"
-      [ -n "$(echo $version | grep "+git")" ] && grade=devel || grade=stable
-      craftctl set version="$version"
-      craftctl set grade="$grade"
-
-    override-build: |
-      set -x
-      npm install -g pnpm
-      TAGS="bindata pam cert" make build
-      install -D gitea "${SNAPCRAFT_PART_INSTALL}/gitea"
-      cp -r options "${SNAPCRAFT_PART_INSTALL}/"
-
+    override-pull: craftctl default && ./snap/part-gitea-pull.sh
+    override-build: ./snap/part-gitea-build.sh
     prime:
       - -etc
       - -usr/lib/systemd