feat(code-review, test-planning): detect the diff base across multiple remotes and git-flow

han-coding/skills/automated-test-planning/scripts/detect-test-context.sh

@@ -24,12 +24,66 @@ echo "git-available: true"
 BRANCH=$(git branch --show-current)
 echo "branch: ${BRANCH:-none}"
 
-# Check for remote and default branch
-if git symbolic-ref --short refs/remotes/origin/HEAD &>/dev/null; then
-  DEFAULT=$(git symbolic-ref --short refs/remotes/origin/HEAD)
-  echo "default-branch: $DEFAULT"
+# Select the base branch to diff against: the candidate whose fork point is
+# nearest the current commit, measured along the branch's own line of work so a
+# candidate the branch merely merged in cannot win on absorbed commits.
 
-  CHANGED=$(git diff --name-only "$DEFAULT...HEAD" 2>/dev/null)
+# HEAD's own line of work is its first-parent history. Resolve HEAD to a commit
+# once so every candidate is measured against the same point even if the ref moves
+# mid-run, then record the line's length. A candidate that contains none of these
+# commits shares no history with the own line, or touches it only through a merge's
+# second parent, and is skipped below.
+HEAD_SHA=$(git rev-parse --verify HEAD 2>/dev/null)
+OWNLINE_COUNT=$(git rev-list --count --first-parent "$HEAD_SHA" 2>/dev/null)
+
+DEFAULT=none
+best_distance=""
+seen=" "
+
+# Fold one candidate ref into the running nearest-wins selection. Its distance is
+# the count of own-line commits not reachable from the candidate. First-parent
+# history is monotone, so the own-line commits a candidate contains form an older
+# run at the bottom of the line, and the count above them is the distance to the
+# candidate's fork point. Note that "--first-parent" limits only the walk from
+# HEAD; the "^$1" exclusion still uses the candidate's full reachability, so a
+# commit the candidate reaches through a merge's second parent counts here just as
+# the old "merge-base --is-ancestor" probe counted it. This runs one rev-list per
+# candidate, not an is-ancestor probe per own-line commit. A ref already seen, or
+# one containing no own-line commit (distance equals the full own-line length, so
+# nothing was excluded), is skipped.
+consider() { # candidate-ref
+  case "$seen" in *" $1 "*) return ;; esac
+  seen="$seen$1 "
+  local distance
+  distance=$(git rev-list --count --first-parent "$HEAD_SHA" "^$1" 2>/dev/null)
+  { [ -n "$distance" ] && [ -n "$OWNLINE_COUNT" ] && [ "$distance" -lt "$OWNLINE_COUNT" ]; } || return
+  if [ -z "$best_distance" ] || [ "$distance" -lt "$best_distance" ]; then
+    best_distance=$distance
+    DEFAULT=$1
+  fi
+}
+
+# Candidate pool, enumerated declared-defaults-first so that under the
+# nearest-wins rule a declared default beats a name-guessed candidate at an
+# equal-distance tie. First, every remote's declared default branch (HEAD).
+while IFS= read -r headref; do
+  ref=$(git symbolic-ref --short "$headref" 2>/dev/null) || continue
+  consider "$ref"
+done < <(git for-each-ref --sort=refname --format='%(refname)' refs/remotes/ 2>/dev/null | grep -E '/HEAD$')
+
+# Then well-known trunk/integration names as local branches, then as each
+# remote's tracking branch.
+for n in main master trunk mainline next develop devel development default dev; do
+  git show-ref --verify -q "refs/heads/$n" && consider "$n"
+  while IFS= read -r ref; do
+    [ -n "$ref" ] && consider "$ref"
+  done < <(git for-each-ref --sort=refname --format='%(refname:short)' "refs/remotes/*/$n" 2>/dev/null)
+done
+
+echo "default-branch: $DEFAULT"
+
+if [ "$DEFAULT" != none ]; then
+  CHANGED=$(git diff --name-only "$DEFAULT...$HEAD_SHA" 2>/dev/null)
   if [ -n "$CHANGED" ]; then
     echo "changed-files-start"
     echo "$CHANGED"
@@ -38,6 +92,5 @@ if git symbolic-ref --short refs/remotes/origin/HEAD &>/dev/null; then
     echo "changed-files: none"
   fi
 else
-  echo "default-branch: none"
   echo "changed-files: none"
 fi

han-coding/skills/code-review/scripts/detect-review-context.sh

@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 # Detect git availability and review context
-# NOTE: Kept in sync with test-planning/scripts/detect-test-context.sh
+# NOTE: Kept in sync with automated-test-planning/scripts/detect-test-context.sh
 
 # Check if git is installed
 if ! command -v git &>/dev/null; then
@@ -24,12 +24,66 @@ echo "git-available: true"
 BRANCH=$(git branch --show-current)
 echo "branch: ${BRANCH:-none}"
 
-# Check for remote and default branch
-if git symbolic-ref --short refs/remotes/origin/HEAD &>/dev/null; then
-  DEFAULT=$(git symbolic-ref --short refs/remotes/origin/HEAD)
-  echo "default-branch: $DEFAULT"
+# Select the base branch to diff against: the candidate whose fork point is
+# nearest the current commit, measured along the branch's own line of work so a
+# candidate the branch merely merged in cannot win on absorbed commits.
 
-  CHANGED=$(git diff --name-only "$DEFAULT...HEAD" 2>/dev/null)
+# HEAD's own line of work is its first-parent history. Resolve HEAD to a commit
+# once so every candidate is measured against the same point even if the ref moves
+# mid-run, then record the line's length. A candidate that contains none of these
+# commits shares no history with the own line, or touches it only through a merge's
+# second parent, and is skipped below.
+HEAD_SHA=$(git rev-parse --verify HEAD 2>/dev/null)
+OWNLINE_COUNT=$(git rev-list --count --first-parent "$HEAD_SHA" 2>/dev/null)
+
+DEFAULT=none
+best_distance=""
+seen=" "
+
+# Fold one candidate ref into the running nearest-wins selection. Its distance is
+# the count of own-line commits not reachable from the candidate. First-parent
+# history is monotone, so the own-line commits a candidate contains form an older
+# run at the bottom of the line, and the count above them is the distance to the
+# candidate's fork point. Note that "--first-parent" limits only the walk from
+# HEAD; the "^$1" exclusion still uses the candidate's full reachability, so a
+# commit the candidate reaches through a merge's second parent counts here just as
+# the old "merge-base --is-ancestor" probe counted it. This runs one rev-list per
+# candidate, not an is-ancestor probe per own-line commit. A ref already seen, or
+# one containing no own-line commit (distance equals the full own-line length, so
+# nothing was excluded), is skipped.
+consider() { # candidate-ref
+  case "$seen" in *" $1 "*) return ;; esac
+  seen="$seen$1 "
+  local distance
+  distance=$(git rev-list --count --first-parent "$HEAD_SHA" "^$1" 2>/dev/null)
+  { [ -n "$distance" ] && [ -n "$OWNLINE_COUNT" ] && [ "$distance" -lt "$OWNLINE_COUNT" ]; } || return
+  if [ -z "$best_distance" ] || [ "$distance" -lt "$best_distance" ]; then
+    best_distance=$distance
+    DEFAULT=$1
+  fi
+}
+
+# Candidate pool, enumerated declared-defaults-first so that under the
+# nearest-wins rule a declared default beats a name-guessed candidate at an
+# equal-distance tie. First, every remote's declared default branch (HEAD).
+while IFS= read -r headref; do
+  ref=$(git symbolic-ref --short "$headref" 2>/dev/null) || continue
+  consider "$ref"
+done < <(git for-each-ref --sort=refname --format='%(refname)' refs/remotes/ 2>/dev/null | grep -E '/HEAD$')
+
+# Then well-known trunk/integration names as local branches, then as each
+# remote's tracking branch.
+for n in main master trunk mainline next develop devel development default dev; do
+  git show-ref --verify -q "refs/heads/$n" && consider "$n"
+  while IFS= read -r ref; do
+    [ -n "$ref" ] && consider "$ref"
+  done < <(git for-each-ref --sort=refname --format='%(refname:short)' "refs/remotes/*/$n" 2>/dev/null)
+done
+
+echo "default-branch: $DEFAULT"
+
+if [ "$DEFAULT" != none ]; then
+  CHANGED=$(git diff --name-only "$DEFAULT...$HEAD_SHA" 2>/dev/null)
   if [ -n "$CHANGED" ]; then
     echo "changed-files-start"
     echo "$CHANGED"
@@ -38,6 +92,5 @@ if git symbolic-ref --short refs/remotes/origin/HEAD &>/dev/null; then
     echo "changed-files: none"
   fi
 else
-  echo "default-branch: none"
   echo "changed-files: none"
 fi