From ee49fc4091b2b77c215d43a9ab427667521a80ac Mon Sep 17 00:00:00 2001
From: zhangning21 <zhangning21@xiaomi.com>
Date: Wed, 10 Jun 2026 11:34:05 +0800
Subject: [PATCH] ci: support PR dependencies via depends-on

This adds a depends-on declaration in the PR description, e.g.:

  depends-on: [apache/nuttx/pull/100 apache/nuttx-apps/pull/200]

Cross-repo PR dependencies, multiple dependent PRs, and dependencies on
other PRs within the same repository can all be combined and supported.
Once CI parses the dependencies, it fetches each dependent PR in the
corresponding local repository and cherry-picks its commits, so the
build runs against the combined code of all involved PRs.

The current approach is intentionally conservative: it requires neither a
GitHub App nor extra write permissions (which we do not have), making it
safe. Its limitation is that it does not write status or comments back to
the dependent PRs, i.e. a failing CI cannot mark the dependent PR as
failed; when the PRs must be merged together, the PR owners need to
coordinate the merge.

Signed-off-by: zhangning21 <zhangning21@xiaomi.com>
---
 .github/workflows/build.yml | 89 +++++++++++++++++++++++++++++++++++++
 1 file changed, 89 insertions(+)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index dd54ff06116f3..be2949f2eb8e1 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -45,9 +45,12 @@ jobs:
       - name: Determine Target Branches
         id: gittargets
         shell: bash
+        env:
+          PR_BODY: ${{ github.event.pull_request.body }}
         run: |
           OS_REF=""
           APPS_REF=""
+          DEPENDS_ON=""
 
           REF=$GITHUB_REF
 
@@ -91,8 +94,35 @@ jobs:
             esac
           fi
 
+          # Parse cross-repo PR dependencies from PR body
+          # Format: depends-on: [apache/nuttx-apps/pull/1234 https://github.com/apache/nuttx/pull/5678]
+          if [ -n "$PR_BODY" ]; then
+            ARRAY_DEPS=$(echo "$PR_BODY" | grep -oE 'depends-on:[[:space:]]*\[[^]]+\]' | head -1) || true
+            if [ -n "$ARRAY_DEPS" ]; then
+              DEPS=$(echo "$ARRAY_DEPS" | grep -oE '(https://github.com/)?apache/nuttx(-apps)?/pull/[0-9]+') || true
+            else
+              DEPS=$(echo "$PR_BODY" | grep -oE 'depends-on:[[:space:]]*(https://github.com/)?apache/nuttx(-apps)?/pull/[0-9]+' | sed 's/depends-on:[[:space:]]*//' | head -1) || true
+            fi
+
+            for DEP in $DEPS; do
+              DEP=$(echo "$DEP" | sed 's|https://github.com/||')
+              DEP_REPO=$(echo "$DEP" | awk -F'/pull/' '{print $1}')
+              DEP_PR_NUM=$(echo "$DEP" | awk -F'/pull/' '{print $2}')
+
+              if [[ "$DEP_REPO" != "apache/nuttx" && "$DEP_REPO" != "apache/nuttx-apps" ]]; then
+                echo "::warning::Ignoring unsupported dependency repo: $DEP_REPO"
+                continue
+              fi
+
+              DEPENDS_ON="$DEPENDS_ON ${DEP_REPO}/pull/${DEP_PR_NUM}"
+            done
+
+            DEPENDS_ON=$(echo "$DEPENDS_ON" | tr ' ' '\n' | awk 'NF && !a[$0]++' | xargs)
+          fi
+
           echo "os_ref=$OS_REF" >> $GITHUB_OUTPUT
           echo "apps_ref=$APPS_REF" >> $GITHUB_OUTPUT
+          echo "depends_on=$DEPENDS_ON" >> $GITHUB_OUTPUT
 
       - name: Checkout nuttx repo
         uses: actions/checkout@v6
@@ -112,6 +142,65 @@ jobs:
           path: sources/apps
           fetch-depth: 1
 
+      - name: Apply depends-on PRs
+        if: ${{ steps.gittargets.outputs.depends_on != '' }}
+        shell: bash
+        env:
+          DEPENDS_ON: ${{ steps.gittargets.outputs.depends_on }}
+        run: |
+          set -euo pipefail
+
+          git config --global user.email "actions@github.com"
+          git config --global user.name "github-actions"
+
+          for DEPENDENCY in $DEPENDS_ON; do
+            DEP_REPO=$(echo "$DEPENDENCY" | awk -F'/pull/' '{print $1}')
+            DEP_PR_NUM=$(echo "$DEPENDENCY" | awk -F'/pull/' '{print $2}')
+
+            case "$DEP_REPO" in
+              "apache/nuttx")
+                REPO_PATH="sources/nuttx"
+                ;;
+              "apache/nuttx-apps")
+                REPO_PATH="sources/apps"
+                ;;
+              *)
+                echo "::error::Unsupported dependency repo: $DEP_REPO"
+                exit 1
+                ;;
+            esac
+
+            echo "Applying dependency ${DEP_REPO}/pull/${DEP_PR_NUM}"
+            if [ -f "$REPO_PATH/.git/shallow" ]; then
+              git -C "$REPO_PATH" fetch --unshallow origin
+            fi
+            git -C "$REPO_PATH" fetch origin "pull/${DEP_PR_NUM}/head:dep-${DEP_PR_NUM}"
+
+            COMMON_BASE=$(git -C "$REPO_PATH" merge-base "dep-${DEP_PR_NUM}" HEAD || true)
+            if [ -z "$COMMON_BASE" ]; then
+              echo "::error::Could not find common base for ${DEP_REPO}/pull/${DEP_PR_NUM}"
+              exit 1
+            fi
+
+            COMMITS=$(git -C "$REPO_PATH" rev-list --reverse "HEAD..dep-${DEP_PR_NUM}") || {
+              echo "::error::Could not list commits for ${DEP_REPO}/pull/${DEP_PR_NUM}"
+              exit 1
+            }
+
+            if [ -z "$COMMITS" ]; then
+              echo "Dependency ${DEP_REPO}/pull/${DEP_PR_NUM} is already included"
+              continue
+            fi
+
+            # shellcheck disable=SC2086
+            if ! git -C "$REPO_PATH" cherry-pick $COMMITS; then
+              echo "::error::cherry-pick failed for ${DEP_REPO}/pull/${DEP_PR_NUM}."
+              echo "::error::If your PR contains merge commits, please rebase instead of merge."
+              git -C "$REPO_PATH" cherry-pick --abort || true
+              exit 1
+            fi
+          done
+
       - name: Tar sources
         run: tar zcf sources.tar.gz sources