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Phlogistiqueclaude
Phlogistique
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claude
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Add tests for rebase and mixed merge/rebase workflows (#30)
Verifies the action works regardless of how the child PR synced with its parent during development: pure rebase, or merge-then-rebase — including cases where the child is NOT fully up to date with the parent at squash-merge time. In all cases, the `git merge origin/$MERGED_BRANCH` step in the action correctly brings the child up to date with whatever commits it was missing, and the synthetic 3-parent merge produces a clean PR diff. Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
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‎.github/workflows/tests.yml‎

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uses: actions/checkout@v4
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- name: Run unit tests
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run: bash tests/test_update_pr_stack.sh
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run: |
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bash tests/test_update_pr_stack.sh
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bash tests/test_rebase_workflow.sh
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bash tests/test_mixed_workflows.sh
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e2e-tests:
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name: E2E Tests

‎README.md‎

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### The solution
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This action tries to fix that in a transparent way. Install it, and hopefully the workflow of stacking + merge during dev + squash merge when landing works.
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This action tries to fix that in a transparent way. Install it, and hopefully the workflow of stacking + merge during dev + squash merge when landing works. It also works if you rebase during development instead of merging.
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---
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‎tests/test_mixed_workflows.sh‎

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#!/bin/bash
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#
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# Test mixed merge/rebase workflows where feature2 is NOT fully up to date
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# with feature1 at the time of squash-merge.
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#
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# Scenarios:
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# A) feature2 rebased onto an intermediate state of feature1, then feature1
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# got more commits that feature2 never picked up.
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# B) feature2 merged feature1 once, then rebased onto a later feature1 state,
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# but feature1 got yet more commits after that.
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set -e
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SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
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source "$SCRIPT_DIR/../command_utils.sh"
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simulate_push() {
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log_cmd git update-ref "refs/remotes/origin/$1" "$1"
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}
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# Extract just the +/- lines from a diff (ignoring headers and context)
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diff_changes() {
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grep '^[+-]' | grep -v '^[+-][+-][+-]'
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}
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run_scenario() {
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local SCENARIO_NAME="$1"
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echo ""
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echo "============================================"
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echo " Scenario $SCENARIO_NAME"
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echo "============================================"
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echo ""
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TEST_REPO=$(mktemp -d)
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cd "$TEST_REPO"
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log_cmd git init -b main
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log_cmd git config user.email "test@example.com"
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log_cmd git config user.name "Test User"
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# 10-line file to keep changes well-separated
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for i in $(seq 1 10); do echo "line $i" >> file.txt; done
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log_cmd git add file.txt
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log_cmd git commit -m "Initial commit"
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simulate_push main
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}
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assert_diff_is() {
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local LABEL="$1"
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local EXPECTED="$2"
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local ACTUAL
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ACTUAL=$(log_cmd git diff main...feature2 | diff_changes)
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if [[ "$ACTUAL" == "$EXPECTED" ]]; then
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echo "✅ $LABEL"
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else
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echo "❌ $LABEL"
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echo "Expected changed lines:"
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echo "$EXPECTED"
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echo "Actual changed lines:"
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echo "$ACTUAL"
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exit 1
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fi
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}
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assert_idempotent() {
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local BEFORE AFTER
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BEFORE=$(git rev-parse feature2)
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run_update_pr_stack
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cd "$TEST_REPO"
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AFTER=$(git rev-parse feature2)
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if [[ "$BEFORE" == "$AFTER" ]]; then
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echo "✅ Idempotent"
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else
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echo "❌ Idempotence failed"
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exit 1
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fi
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}
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squash_merge_feature1() {
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log_cmd git checkout main
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log_cmd git merge --squash feature1
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log_cmd git commit -m "Squash merge feature1"
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SQUASH_COMMIT=$(git rev-parse HEAD)
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simulate_push main
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echo "Squash commit: $SQUASH_COMMIT"
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}
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run_update_pr_stack() {
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log_cmd \
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env \
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SQUASH_COMMIT=$SQUASH_COMMIT \
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MERGED_BRANCH=feature1 \
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TARGET_BRANCH=main \
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GH="$SCRIPT_DIR/mock_gh.sh" \
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GIT="$SCRIPT_DIR/mock_git.sh" \
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$SCRIPT_DIR/../update-pr-stack.sh
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}
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########################################################################
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# Scenario A: rebase onto intermediate feature1, then feature1 advances
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########################################################################
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run_scenario "A: rebased onto intermediate feature1, then feature1 advances"
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# feature1: two commits (lines 2 and 3)
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log_cmd git checkout -b feature1
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sed -i '2s/.*/f1 commit 1/' file.txt
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log_cmd git add file.txt
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log_cmd git commit -m "f1: commit 1"
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simulate_push feature1
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# feature2: branched from feature1 after commit 1, changes line 9
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log_cmd git checkout -b feature2
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sed -i '9s/.*/f2 content/' file.txt
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log_cmd git add file.txt
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log_cmd git commit -m "f2: change line 9"
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simulate_push feature2
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# feature1 gets commit 2
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log_cmd git checkout feature1
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sed -i '3s/.*/f1 commit 2/' file.txt
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log_cmd git add file.txt
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log_cmd git commit -m "f1: commit 2"
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simulate_push feature1
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# Developer rebases feature2 onto feature1 (picks up commit 2)
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log_cmd git checkout feature2
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log_cmd git rebase feature1
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simulate_push feature2
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# feature1 gets commit 3 — feature2 does NOT pick this up
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log_cmd git checkout feature1
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sed -i '4s/.*/f1 commit 3/' file.txt
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log_cmd git add file.txt
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log_cmd git commit -m "f1: commit 3"
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simulate_push feature1
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echo ""
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echo "=== Graph before squash-merge ==="
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log_cmd git log --graph --oneline --all
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echo ""
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squash_merge_feature1
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run_update_pr_stack
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cd "$TEST_REPO"
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# The diff should show only feature2's unique change
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assert_diff_is "Scenario A: diff shows only f2's change" "$(cat <<'EOF'
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-line 9
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+f2 content
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EOF
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)"
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assert_idempotent
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########################################################################
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# Scenario B: merge then rebase, then feature1 advances again
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########################################################################
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run_scenario "B: merge then rebase, then feature1 advances again"
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# feature1: commit 1 (line 2)
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log_cmd git checkout -b feature1
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sed -i '2s/.*/f1 commit 1/' file.txt
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log_cmd git add file.txt
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log_cmd git commit -m "f1: commit 1"
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simulate_push feature1
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# feature2 from feature1, changes line 9
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log_cmd git checkout -b feature2
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sed -i '9s/.*/f2 content/' file.txt
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log_cmd git add file.txt
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log_cmd git commit -m "f2: change line 9"
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simulate_push feature2
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# feature1 gets commit 2
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log_cmd git checkout feature1
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sed -i '3s/.*/f1 commit 2/' file.txt
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log_cmd git add file.txt
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log_cmd git commit -m "f1: commit 2"
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simulate_push feature1
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# Developer merges feature1 into feature2
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log_cmd git checkout feature2
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log_cmd git merge --no-edit feature1
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simulate_push feature2
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# feature1 gets commit 3
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log_cmd git checkout feature1
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sed -i '4s/.*/f1 commit 3/' file.txt
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log_cmd git add file.txt
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log_cmd git commit -m "f1: commit 3"
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simulate_push feature1
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# Developer rebases feature2 onto latest feature1 (rewrite away the merge)
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log_cmd git checkout feature2
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log_cmd git rebase feature1
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simulate_push feature2
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# feature1 gets commit 4 — feature2 does NOT pick this up
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log_cmd git checkout feature1
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sed -i '5s/.*/f1 commit 4/' file.txt
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log_cmd git add file.txt
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log_cmd git commit -m "f1: commit 4"
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simulate_push feature1
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echo ""
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echo "=== Graph before squash-merge ==="
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log_cmd git log --graph --oneline --all
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echo ""
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squash_merge_feature1
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run_update_pr_stack
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cd "$TEST_REPO"
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assert_diff_is "Scenario B: diff shows only f2's change" "$(cat <<'EOF'
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-line 9
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+f2 content
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EOF
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)"
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assert_idempotent
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########################################################################
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echo ""
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echo "All mixed-workflow tests passed! 🎉"

‎tests/test_rebase_workflow.sh‎

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#!/bin/bash
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#
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# Test that the update-pr-stack mechanism works when PRs are rebased during
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# development (as opposed to using merge commits to sync with the parent).
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#
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# Scenario:
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# 1. main ← feature1 ← feature2 (linear stack)
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# 2. feature1 gets an additional commit AFTER feature2 was branched
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# 3. Developer rebases feature2 onto the updated feature1
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# 4. feature1 is squash-merged into main
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# 5. Action runs → feature2 should get a correct PR diff against main
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set -e
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SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
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source "$SCRIPT_DIR/../command_utils.sh"
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simulate_push() {
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local branch_name="$1"
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log_cmd git update-ref "refs/remotes/origin/$branch_name" "$branch_name"
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}
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TEST_REPO=$(mktemp -d)
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cd "$TEST_REPO"
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echo "Created test repo at $TEST_REPO"
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log_cmd git init -b main
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log_cmd git config user.email "test@example.com"
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log_cmd git config user.name "Test User"
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# Initial commit on main — use enough lines to avoid adjacent-change conflicts
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for i in $(seq 1 10); do echo "line $i" >> file.txt; done
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log_cmd git add file.txt
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log_cmd git commit -m "Initial commit"
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simulate_push main
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# feature1: modify line 2 (top region)
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log_cmd git checkout -b feature1
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sed -i '2s/.*/Feature 1 first change/' file.txt
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log_cmd git add file.txt
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log_cmd git commit -m "feature1: first commit"
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simulate_push feature1
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# feature2: branched from feature1, modify line 9 (bottom region, far away)
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log_cmd git checkout -b feature2
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sed -i '9s/.*/Feature 2 content/' file.txt
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log_cmd git add file.txt
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log_cmd git commit -m "feature2: change line 9"
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simulate_push feature2
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# Now feature1 gets an additional commit modifying line 3 (still top region)
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log_cmd git checkout feature1
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sed -i '3s/.*/Feature 1 second change/' file.txt
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log_cmd git add file.txt
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log_cmd git commit -m "feature1: second commit"
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simulate_push feature1
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FEATURE1_TIP=$(git rev-parse HEAD)
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# Developer rebases feature2 onto the updated feature1
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log_cmd git checkout feature2
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log_cmd git rebase feature1
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simulate_push feature2
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echo ""
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echo "=== State before squash-merge ==="
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log_cmd git log --graph --oneline --all
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echo ""
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# Squash-merge feature1 into main (simulated via cherry-pick --no-commit + commit)
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log_cmd git checkout main
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# Use merge --squash to properly squash all of feature1's commits
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log_cmd git merge --squash feature1
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log_cmd git commit -m "Squash merge feature1"
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SQUASH_COMMIT=$(git rev-parse HEAD)
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simulate_push main
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echo ""
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echo "Squash commit: $SQUASH_COMMIT"
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echo ""
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# Run the action
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run_update_pr_stack() {
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log_cmd \
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env \
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SQUASH_COMMIT=$SQUASH_COMMIT \
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MERGED_BRANCH=feature1 \
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TARGET_BRANCH=main \
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GH="$SCRIPT_DIR/mock_gh.sh" \
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GIT="$SCRIPT_DIR/mock_git.sh" \
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$SCRIPT_DIR/../update-pr-stack.sh
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}
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run_update_pr_stack
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cd "$TEST_REPO"
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# Verify: squash commit is an ancestor of feature2
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if log_cmd git merge-base --is-ancestor "$SQUASH_COMMIT" feature2; then
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echo "✅ feature2 includes the squash commit"
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else
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echo "❌ feature2 does not include the squash commit"
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log_cmd git log --graph --oneline --all
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exit 1
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fi
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# Verify: triple-dot diff main...feature2 shows ONLY feature2's unique change
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# We expect the diff to show only feature2's unique change (line 9).
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# Strip index lines and hunk header function-name context for stable comparison.
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EXPECTED_DIFF=$(cat <<'EOF'
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-line 9
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+Feature 2 content
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EOF
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)
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ACTUAL_DIFF=$(log_cmd git diff main...feature2 | grep '^[+-]' | grep -v '^[+-][+-][+-]')
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if [[ "$ACTUAL_DIFF" == "$EXPECTED_DIFF" ]]; then
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echo "✅ Triple-dot diff main...feature2 shows only feature2's unique changes"
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else
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echo "❌ Triple-dot diff is wrong"
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echo "Expected:"
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echo "$EXPECTED_DIFF"
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echo "Actual:"
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echo "$ACTUAL_DIFF"
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diff <(echo "$EXPECTED_DIFF") <(echo "$ACTUAL_DIFF") || true
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exit 1
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fi
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# Verify idempotence
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FEATURE2_BEFORE=$(git rev-parse feature2)
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run_update_pr_stack
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cd "$TEST_REPO"
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FEATURE2_AFTER=$(git rev-parse feature2)
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if [[ "$FEATURE2_BEFORE" == "$FEATURE2_AFTER" ]]; then
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echo "✅ Idempotence: re-running produces no new commits"
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else
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echo "❌ Idempotence failed"
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exit 1
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fi
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echo ""
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echo "All rebase-workflow tests passed! 🎉"
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echo "Test repository remains at: $TEST_REPO for inspection"

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