scrub: some left over fixes

These fixes were in intermediate merge commits intended to be squashed
into the PR that would have been merged after as it was rebased, and
some things that slipped through the cracks.

Remove conflict_skip map and per-commit skip check in check_one_commit,
commits are filtered ahead of time.

Move flake_ordered/quick_ordered construction before the conflict check.

Remove some straggler /dev/null redirects

Author: nothingmuch

contrib/scrub-commit-history.sh

@@ -168,7 +168,6 @@ if [ "$quick" = only ] && [ "$all_checks" = true ]; then
 fi
 
 repo_root=$(git rev-parse --show-toplevel)
-
 system=$(nix eval --offline --raw --impure --expr builtins.currentSystem)
 
 # Resolve VCS mode
@@ -347,10 +346,6 @@ expect_fail_matches_checks() {
 # Appends to build_failed[] on failure.
 check_one_commit() {
   local hash=$1
-  if [ -n "${conflict_skip[$hash]:-}" ]; then
-    echo "  - $(fmt_commit "$hash") (skipped: conflict)"
-    return 0
-  fi
   if [ -n "${no_flake[$hash]:-}" ]; then
     if [ "$no_skip_missing" = true ]; then
       echo "  ✗ $(fmt_commit "$hash") (no flake.nix)"
@@ -435,15 +430,27 @@ for hash in "${linear[@]}"; do
   fi
 done
 
+# Build phase-specific ordered arrays (pre-filtered)
+flake_ordered=()
+quick_ordered=()
+for idx in "${ordered[@]}"; do
+  hash=${linear[$idx]}
+  [ -z "${no_flake[$hash]:-}" ] || continue
+  flake_ordered+=("$idx")
+  [ -z "${no_quick[$hash]:-}" ] || continue
+  quick_ordered+=("$idx")
+done
+
+# Check each commit message for unresolved work-item markers
 # Conflict check — jj conflict trees and git conflict markers
 conflict_failed=()
 echo "Checking for conflicts..."
 for idx in "${ordered[@]}"; do
   hash=${linear[$idx]}
   reason=""
-  if git ls-tree --name-only "$hash" 2>/dev/null | grep -qE '^\.jj(conflict-|-do-not-resolve)'; then
+  if git ls-tree --name-only "$hash" | grep -qE '^\.jj(conflict-|-do-not-resolve)'; then
     reason="jj conflict tree"
-  elif git grep -q -E '<{7}|>{7}|={7}' "$hash" -- 2>/dev/null; then
+  elif git grep -q -E '<{7}|>{7}|={7}' "$hash" --; then
     reason="conflict markers"
   fi
   if [ -n "$reason" ]; then
@@ -457,22 +464,6 @@ else
   echo "  all clean"
 fi
 
-# Build skip map so flake checks are not wasted on conflicted commits
-declare -A conflict_skip
-for h in "${conflict_failed[@]}"; do conflict_skip[$h]=1; done
-
-# Build phase-specific ordered arrays (pre-filtered)
-flake_ordered=()
-quick_ordered=()
-for idx in "${ordered[@]}"; do
-  hash=${linear[$idx]}
-  [ -z "${conflict_skip[$hash]:-}" ] || continue
-  [ -z "${no_flake[$hash]:-}" ] || continue
-  flake_ordered+=("$idx")
-  [ -z "${no_quick[$hash]:-}" ] || continue
-  quick_ordered+=("$idx")
-done
-
 msg_failed=()
 echo "Checking commit messages..."
 for idx in "${ordered[@]}"; do
@@ -502,8 +493,8 @@ if git cat-file -e "$tip_hash:.gitignore" 2>/dev/null; then
   echo "Checking gitignore monotonicity..."
   for idx in "${ordered[@]}"; do
     hash=${linear[$idx]}
-    leaked=$(git ls-tree -r --name-only "$hash" 2>/dev/null |
-      git -C "$tmpdir/repo" check-ignore --stdin 2>/dev/null || true)
+    leaked=$(git ls-tree -r --name-only "$hash" |
+      git -C "$tmpdir/repo" check-ignore --stdin || true)
     if [ -n "$leaked" ]; then
       first=$(echo "$leaked" | head -1)
       count=$(echo "$leaked" | wc -l)