test(#795): make PR diff fixtures hermetic

packages/mosaic/framework/tools/codex/test-pr-diff-context.sh

@@ -1,5 +1,5 @@
 #!/bin/bash
-# Regression coverage for Gitea PR diff construction and fail-closed review behavior.
+# Hermetic regression coverage for Gitea PR diff construction and fail-closed reviews.
 set -euo pipefail
 
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
@@ -13,108 +13,60 @@ fail() {
 
 assert_contains() {
     local haystack="$1" needle="$2"
-    [[ "$haystack" == *"$needle"* ]] || fail "expected output to contain: $needle"
+    if [[ "$haystack" != *"$needle"* ]]; then
+        printf 'actual output:\n%s\n' "$haystack" >&2
+        fail "expected output to contain: $needle"
+    fi
 }
 
-# A fresh clone's local HEAD is unrelated to PR #795, whose changes target the
+# Prevent CI-provided repository context from leaking into the fixture repositories.
-# synthetic non-main base release/next and exist only at the provider PR ref.
+unset GIT_DIR GIT_WORK_TREE GIT_INDEX_FILE GIT_OBJECT_DIRECTORY \
-# The git stub returns the PR patch only for those two explicit fetched refs.
+    GIT_ALTERNATE_OBJECT_DIRECTORIES GIT_COMMON_DIR
-if [[ "${1:-all}" != "fail-closed" ]]; then
+export GIT_AUTHOR_NAME="Codex Fixture"
-    FETCH_LOG="$TMP_DIR/fetch.log"
+export GIT_AUTHOR_EMAIL="codex-fixture@example.test"
-    DIFF_LOG="$TMP_DIR/diff.log"
+export GIT_COMMITTER_NAME="$GIT_AUTHOR_NAME"
-    export FETCH_LOG DIFF_LOG
+export GIT_COMMITTER_EMAIL="$GIT_AUTHOR_EMAIL"
+export GITEA_LOGIN="fixture"
+export GITEA_TOKEN="fixture-token"
+export GITEA_URL="file://$TMP_DIR"
 
-    (
+create_pr_fixture() {
-        # shellcheck source=common.sh
+    local fixture_root="$1" head_mode="$2"
-        source "$SCRIPT_DIR/common.sh"
+    local origin="$fixture_root/origin.git"
+    local seed="$fixture_root/seed"
+    local work="$fixture_root/work"
+    local base_sha head_sha
 
-        detect_platform() {
+    mkdir -p "$fixture_root"
-            PLATFORM=gitea
+    git init --quiet --bare "$origin"
-            export PLATFORM
+    git init --quiet --initial-branch=release/next "$seed"
-        }
+    printf 'base\n' > "$seed/pr-change.ts"
+    git -C "$seed" add pr-change.ts
+    git -C "$seed" commit --quiet -m "fixture base"
+    base_sha=$(git -C "$seed" rev-parse HEAD)
+    git -C "$seed" remote add origin "$origin"
+    git -C "$seed" push --quiet origin release/next
+    git --git-dir="$origin" symbolic-ref HEAD refs/heads/release/next
 
-        tea() {
+    if [[ "$head_mode" == "changed" ]]; then
-            if [[ "$*" == "pr list --fields index,base --output simple" ]]; then
+        git -C "$seed" switch --quiet -c feature/pr-795
-                printf '795 release/next\n'
+        printf 'actual-pr-change\n' > "$seed/pr-change.ts"
-                return 0
+        git -C "$seed" commit --quiet -am "fixture PR head"
-            fi
+        head_sha=$(git -C "$seed" rev-parse HEAD)
-            return 1
+        git -C "$seed" push --quiet origin HEAD:refs/pull/795/head
-        }
+    else
-
+        head_sha="$base_sha"
-        git() {
+        git --git-dir="$origin" update-ref refs/pull/795/head "$head_sha"
-            case "${1:-}" in
-                remote)
-                    printf 'https://git.example.test/mosaicstack/stack.git\n'
-                    ;;
-                fetch)
-                    printf '%s\n' "$*" >> "$FETCH_LOG"
-                    ;;
-                diff)
-                    printf '%s\n' "$*" >> "$DIFF_LOG"
-                    if [[ "$*" == *"refs/remotes/origin/release/next...refs/remotes/origin/pr/795/head"* && "$*" != *"HEAD"* ]]; then
-                        cat <<'DIFF'
-diff --git a/pr-change.ts b/pr-change.ts
---- a/pr-change.ts
-+++ b/pr-change.ts
-@@ -1 +1 @@
--old
-+actual-pr-change
-DIFF
-                    fi
-                    ;;
-                *)
-                    return 1
-                    ;;
-            esac
-        }
-
-        diff_context=$(build_diff_context pr 795)
-        assert_contains "$diff_context" "actual-pr-change"
-    )
-
-    assert_contains "$(cat "$FETCH_LOG" 2>/dev/null || true)" "refs/heads/release/next:refs/remotes/origin/release/next"
-    assert_contains "$(cat "$FETCH_LOG" 2>/dev/null || true)" "refs/pull/795/head"
-    assert_contains "$(cat "$DIFF_LOG" 2>/dev/null || true)" "refs/remotes/origin/release/next...refs/remotes/origin/pr/795/head"
-    if grep -q 'HEAD' "$DIFF_LOG" 2>/dev/null; then
-        fail "Gitea PR diff used local HEAD"
     fi
-    echo "ok - Gitea PR mode fetches and diffs explicit non-main base and PR head refs"
-fi
 
-# Exercise both CLI paths with all provider/network mutations stubbed. An empty
+    # Gitea's provider-owned PR head ref now exists in the local bare origin.
-# PR diff must fail before Codex runs and before either auto-post path can run.
+    git clone --quiet "$origin" "$work"
-if [[ "${1:-all}" != "pr-head" ]]; then
+    printf '%s\n' "$work"
-    SANDBOX="$TMP_DIR/sandbox"
+}
-    mkdir -p "$SANDBOX/tools/codex/schemas" "$SANDBOX/tools/git" "$SANDBOX/bin"
-    cp "$SCRIPT_DIR/common.sh" \
-        "$SCRIPT_DIR/codex-code-review.sh" \
-        "$SCRIPT_DIR/codex-security-review.sh" \
-        "$SANDBOX/tools/codex/"
-    cp "$SCRIPT_DIR/schemas/code-review-schema.json" \
-        "$SCRIPT_DIR/schemas/security-review-schema.json" \
-        "$SANDBOX/tools/codex/schemas/"
 
-    cat > "$SANDBOX/tools/git/detect-platform.sh" <<'STUB'
+FAKE_BIN="$TMP_DIR/bin"
-detect_platform() { PLATFORM=gitea; export PLATFORM; }
+mkdir -p "$FAKE_BIN"
-get_repo_info() { printf 'mosaicstack/stack\n'; }
+cat > "$FAKE_BIN/tea" <<'STUB'
-STUB
-    cat > "$SANDBOX/tools/git/pr-review.sh" <<'STUB'
-#!/bin/bash
-printf 'POST %s\n' "$*" >> "$POST_LOG"
-STUB
-    chmod +x "$SANDBOX/tools/git/pr-review.sh"
-
-    cat > "$SANDBOX/bin/git" <<'STUB'
-#!/bin/bash
-case "${1:-}" in
-    rev-parse) exit 0 ;;
-    remote) printf 'https://git.example.test/mosaicstack/stack.git\n' ;;
-    fetch) printf 'FETCH %s\n' "$*" >> "$FETCH_LOG" ;;
-    diff) exit 0 ;;
-    *) exit 1 ;;
-esac
-STUB
-    cat > "$SANDBOX/bin/tea" <<'STUB'
 #!/bin/bash
 if [[ "$*" == "pr list --fields index,base --output simple" ]]; then
     printf '795 release/next\n'
@@ -122,12 +74,62 @@ if [[ "$*" == "pr list --fields index,base --output simple" ]]; then
 fi
 exit 1
 STUB
-    cat > "$SANDBOX/bin/codex" <<'STUB'
+cat > "$FAKE_BIN/codex" <<'STUB'
 #!/bin/bash
 printf 'CODEX %s\n' "$*" >> "$CODEX_LOG"
 exit 99
 STUB
-    chmod +x "$SANDBOX/bin/git" "$SANDBOX/bin/tea" "$SANDBOX/bin/codex"
+chmod +x "$FAKE_BIN/tea" "$FAKE_BIN/codex"
+export PATH="$FAKE_BIN:$PATH"
+
+# The valid fixture is a fresh clone on the non-main base. The PR head exists only
+# at refs/pull/795/head, so local HEAD cannot accidentally satisfy the assertion.
+if [[ "${1:-all}" != "fail-closed" ]]; then
+    VALID_WORK=$(create_pr_fixture "$TMP_DIR/valid" changed)
+    (
+        cd "$VALID_WORK"
+        # shellcheck source=common.sh
+        source "$SCRIPT_DIR/common.sh"
+        diff_context=$(build_diff_context pr 795)
+        assert_contains "$diff_context" "actual-pr-change"
+
+        base_sha=$(git rev-parse refs/remotes/origin/release/next)
+        head_sha=$(git rev-parse refs/remotes/origin/pr/795/head)
+        local_sha=$(git rev-parse HEAD)
+        [[ "$local_sha" == "$base_sha" ]] || fail "fixture clone is not on the PR base"
+        [[ "$head_sha" != "$base_sha" ]] || fail "fixture PR head does not differ from its base"
+        git show-ref --verify --quiet refs/remotes/origin/pr/795/head || \
+            fail "fetched PR head ref is missing"
+        [[ "$(git diff --name-only "${base_sha}...${head_sha}")" == "pr-change.ts" ]] || \
+            fail "explicit PR refs do not contain the fixture change"
+        if git show-ref --verify --quiet refs/heads/main || \
+            git show-ref --verify --quiet refs/remotes/origin/main; then
+            fail "fixture unexpectedly contains a main ref"
+        fi
+    )
+    echo "ok - Gitea PR mode fetches and diffs explicit non-main base and PR head refs"
+fi
+
+# Build an empty PR entirely inside another local repository. Both review wrappers
+# must emit the PR-numbered error before Codex or the stubbed post path can execute.
+if [[ "${1:-all}" != "pr-head" ]]; then
+    EMPTY_WORK=$(create_pr_fixture "$TMP_DIR/empty" empty)
+    SANDBOX="$TMP_DIR/sandbox"
+    mkdir -p "$SANDBOX/tools/codex/schemas" "$SANDBOX/tools/git"
+    cp "$SCRIPT_DIR/common.sh" \
+        "$SCRIPT_DIR/codex-code-review.sh" \
+        "$SCRIPT_DIR/codex-security-review.sh" \
+        "$SANDBOX/tools/codex/"
+    cp "$SCRIPT_DIR/schemas/code-review-schema.json" \
+        "$SCRIPT_DIR/schemas/security-review-schema.json" \
+        "$SANDBOX/tools/codex/schemas/"
+    cp "$SCRIPT_DIR/../git/detect-platform.sh" "$SANDBOX/tools/git/"
+
+    cat > "$SANDBOX/tools/git/pr-review.sh" <<'STUB'
+#!/bin/bash
+printf 'POST %s\n' "$*" >> "$POST_LOG"
+STUB
+    chmod +x "$SANDBOX/tools/git/pr-review.sh"
 
     POST_LOG="$TMP_DIR/post.log"
     CODEX_LOG="$TMP_DIR/codex.log"
@@ -138,16 +140,19 @@ STUB
         : > "$CODEX_LOG"
         review_script="$SANDBOX/tools/codex/codex-${review_kind}-review.sh"
         set +e
-        PATH="$SANDBOX/bin:$PATH" "$review_script" -n 795 \
+        (
-            >"$TMP_DIR/${review_kind}.stdout" 2>"$TMP_DIR/${review_kind}.stderr"
+            cd "$EMPTY_WORK"
+            "$review_script" -n 795
+        ) >"$TMP_DIR/${review_kind}.stdout" 2>"$TMP_DIR/${review_kind}.stderr"
         review_status=$?
         set -e
 
+        stderr_text=$(cat "$TMP_DIR/${review_kind}.stderr")
         [[ "$review_status" -ne 0 ]] || fail "${review_kind} review returned success for an empty PR diff"
         [[ ! -s "$CODEX_LOG" ]] || fail "Codex ran for an empty ${review_kind} PR diff"
         [[ ! -s "$POST_LOG" ]] || fail "${review_kind} review auto-post ran for an empty PR diff"
-        assert_contains "$(cat "$TMP_DIR/${review_kind}.stderr")" "Error:"
+        assert_contains "$stderr_text" "Error:"
-        assert_contains "$(cat "$TMP_DIR/${review_kind}.stderr")" "PR #795"
+        assert_contains "$stderr_text" "PR #795"
         echo "ok - empty ${review_kind} PR diff fails closed before Codex and auto-post"
     done
 fi