Merge remote-tracking branch 'refs/remotes/tmux-openbsd/master'

* refs/remotes/tmux-openbsd/master:
  build: don't exit
  build: always attempt portable merge
  build: capture openbsd-base before filtering
  build: fetch cutover master before merge
  Use _exit in child after fork, from Yayo Razo in GitHub issue 5376.
  Add missing calloc check and use fatal. Prompted by a similar change from Yayo Razo.
  actions: use published openbsd-git as base update
  github actions: automate updates
  Do not make pty fds blocking again until all the data has been consumed or control mode clients can get stuck, GitHub issue 5356 from Ben Maurer.
  Add formats and events for OSC 133 commmands, as well as a -T flag to set-hook -B to only fire when the format is true.
  Replace the notification system with events. Events can carry a payload of additional payload (to reduce problems with lifetime of objects) and are delivered to one or more event sinks. This is more powerful and reduces the complex dependencies between control mode and hooks. Events are now used for hooks, control mode notifications and for monitors (set-hook -B).

.github/workflows/update-openbsd-and-portable.yml

@@ -0,0 +1,174 @@
+name: Update OpenBSD tmux and portable
+
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: "17 3 * * *"
+
+permissions:
+  contents: write
+
+concurrency:
+  group: update-openbsd-and-portable
+  cancel-in-progress: false
+
+env:
+  OPENBSD_SRC_URL: https://github.com/openbsd/src.git
+  OPENBSD_SRC_DIR: openbsd-src
+  CUTOVER_DIR: tmux-openbsd-cutover
+  PORTABLE_DIR: tmux-portable
+  PORTABLE_REPO: ${{ vars.TMUX_PORTABLE_REPO }}
+
+jobs:
+  update:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Configure Git identity
+        run: |
+          git config --global user.name "tmux update bot"
+          git config --global user.email "actions@github.com"
+
+      - name: Install git-filter-repo
+        run: python3 -m pip install --user git-filter-repo
+
+      - name: Checkout cutover repository
+        uses: actions/checkout@v4
+        with:
+          path: ${{ env.CUTOVER_DIR }}
+          fetch-depth: 0
+          token: ${{ secrets.UPDATE_TOKEN || github.token }}
+
+      - name: Check portable repo setting
+        run: |
+          if [ -z "$PORTABLE_REPO" ]; then
+            echo "Set repository variable TMUX_PORTABLE_REPO, for example owner/tmux-portable." >&2
+            exit 1
+          fi
+
+      - name: Checkout portable repository
+        uses: actions/checkout@v4
+        with:
+          repository: ${{ env.PORTABLE_REPO }}
+          path: ${{ env.PORTABLE_DIR }}
+          fetch-depth: 0
+          token: ${{ secrets.UPDATE_TOKEN }}
+
+      - name: Restore OpenBSD source clone cache
+        id: openbsd-cache
+        uses: actions/cache/restore@v4
+        with:
+          path: ${{ env.OPENBSD_SRC_DIR }}
+          key: openbsd-src-blobless-${{ runner.os }}-${{ github.run_id }}
+          restore-keys: |
+            openbsd-src-blobless-${{ runner.os }}-
+
+      - name: Refresh OpenBSD source clone
+        run: |
+          set -eu
+
+          if [ ! -d "$OPENBSD_SRC_DIR/.git" ]; then
+            git clone --filter=blob:none --no-tags --single-branch --branch master \
+              "$OPENBSD_SRC_URL" "$OPENBSD_SRC_DIR"
+          fi
+
+          cd "$OPENBSD_SRC_DIR"
+          git remote set-url origin "$OPENBSD_SRC_URL"
+          git fetch --filter=blob:none --no-tags origin master
+          git switch -C master origin/master
+
+      - name: Capture published OpenBSD tmux base
+        id: openbsd-base
+        run: |
+          set -eu
+
+          cd "$CUTOVER_DIR"
+          if ! git rev-parse --verify -q origin/openbsd-git >/dev/null; then
+            echo "origin/openbsd-git is missing; publish the openbsd-git branch before running updates." >&2
+            exit 1
+          fi
+          echo "sha=$(git rev-parse origin/openbsd-git)" >> "$GITHUB_OUTPUT"
+
+      - name: Filter OpenBSD tmux history
+        run: |
+          set -eu
+
+          cd "$OPENBSD_SRC_DIR"
+          git switch -C tmux-openbsd origin/master
+          git filter-repo \
+            --force \
+            --refs tmux-openbsd \
+            --path usr.bin/tmux/ \
+            --path-rename usr.bin/tmux/: \
+            --replace-refs delete-no-add
+
+          git push "../$CUTOVER_DIR" tmux-openbsd:refs/heads/openbsd-git
+
+      - name: Update cutover master
+        id: cutover
+        run: |
+          set -eu
+
+          cd "$CUTOVER_DIR"
+          git switch master
+
+          old_base="${{ steps.openbsd-base.outputs.sha }}"
+          new_base=$(git rev-parse openbsd-git)
+
+          if [ "$old_base" = "$new_base" ]; then
+            echo "changed=false" >> "$GITHUB_OUTPUT"
+            echo "No new OpenBSD tmux commits to import; continuing to portable merge."
+          else
+            if ! git merge-base --is-ancestor "$old_base" "$new_base"; then
+              echo "new openbsd-git is not a descendant of origin/openbsd-git; aborting." >&2
+              exit 1
+            fi
+
+            git cherry-pick "$old_base..$new_base"
+            echo "changed=true" >> "$GITHUB_OUTPUT"
+          fi
+
+      - name: Push cutover repository
+        if: steps.cutover.outputs.changed == 'true'
+        run: |
+          set -eu
+
+          cd "$CUTOVER_DIR"
+          git push origin master openbsd-git
+
+      - name: Merge cutover into portable
+        id: portable
+        run: |
+          set -eu
+
+          cd "$PORTABLE_DIR"
+          git config remote.tmux-openbsd.tagOpt --no-tags
+
+          if git remote get-url tmux-openbsd >/dev/null 2>&1; then
+            git remote set-url tmux-openbsd "../$CUTOVER_DIR"
+          else
+            git remote add tmux-openbsd "../$CUTOVER_DIR"
+          fi
+
+          git fetch --no-tags tmux-openbsd master:refs/remotes/tmux-openbsd/master
+          git switch master
+          git merge --no-ff --log refs/remotes/tmux-openbsd/master
+          if git diff --quiet origin/master..master; then
+            echo "changed=false" >> "$GITHUB_OUTPUT"
+          else
+            echo "changed=true" >> "$GITHUB_OUTPUT"
+          fi
+
+      - name: Push portable repository
+        if: steps.portable.outputs.changed == 'true'
+        run: |
+          set -eu
+
+          cd "$PORTABLE_DIR"
+          git push origin master
+
+      - name: Save OpenBSD source clone cache
+        if: always()
+        uses: actions/cache/save@v4
+        with:
+          path: ${{ env.OPENBSD_SRC_DIR }}
+          key: openbsd-src-blobless-${{ runner.os }}-${{ github.run_id }}