[PATCH v8 09/10] commit-reach: move min_generation check into paint_queue_get()

From: Kristofer Karlsson <[email protected]>

Consolidate the min_generation termination condition into
paint_queue_get(), alongside the existing stale-entry and
side-exhaustion checks.

Move last_gen into struct paint_state so that
commit_graph_generation() is called exactly once per dequeued commit
and the result is shared across all termination checks and the
monotonicity BUG assertion.

Signed-off-by: Kristofer Karlsson <[email protected]>
---
 commit-reach.c | 31 ++++++++++++++++++-------------
 1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/commit-reach.c b/commit-reach.c
index 7c5bbe00c3..32e65a52b5 100644
--- a/commit-reach.c
+++ b/commit-reach.c
@@ -90,6 +90,8 @@ struct paint_state {
 	size_t parent2_count;
 	size_t mb_candidate_count;
 	int gen_ordered;
+	timestamp_t min_generation;
+	timestamp_t last_gen;
 	timestamp_t topo_ceiling;
 };
 
@@ -140,11 +142,23 @@ static void paint_queue_put(struct paint_state *state,
 static struct commit *paint_queue_get(struct paint_state *state)
 {
 	struct commit *commit = prio_queue_get(&state->queue);
+	timestamp_t generation;
 
 	if (!commit)
 		return NULL;
 
 	commit->object.flags &= ~ENQUEUED;
+	generation = commit_graph_generation(commit);
+
+	if (state->min_generation && generation > state->last_gen)
+		BUG("bad generation skip %"PRItime" > %"PRItime" at %s",
+		    generation, state->last_gen,
+		    oid_to_hex(&commit->object.oid));
+	state->last_gen = generation;
+
+	/* generation cutoff */
+	if (generation < state->min_generation)
+		return NULL;
 
 	/*
 	 * Check exit condition before decrementing: the counters
@@ -159,7 +173,7 @@ static struct commit *paint_queue_get(struct paint_state *state)
 		/* one side is exhausted */
 		if ((!state->parent1_count || !state->parent2_count) &&
 		    state->gen_ordered &&
-		    commit_graph_generation(commit) < state->topo_ceiling)
+		    generation < state->topo_ceiling)
 			return NULL;
 	}
 
@@ -186,9 +200,10 @@ static int paint_down_to_common(struct repository *r,
 	struct commit *commit;
 	int i;
 	int steps = 0;
-	timestamp_t last_gen = GENERATION_NUMBER_INFINITY;
 	struct commit_list **tail = result;
 
+	state.min_generation = min_generation;
+	state.last_gen = GENERATION_NUMBER_INFINITY;
 	state.topo_ceiling = corrected_commit_dates_enabled(r)
 		? GENERATION_NUMBER_INFINITY
 		: GENERATION_NUMBER_V1_MAX;
@@ -210,18 +225,8 @@ static int paint_down_to_common(struct repository *r,
 	while ((commit = paint_queue_get(&state))) {
 		struct commit_list *parents;
 		int flags;
-		timestamp_t generation = commit_graph_generation(commit);
 		steps++;
 
-		if (min_generation && generation > last_gen)
-			BUG("bad generation skip %"PRItime" > %"PRItime" at %s",
-			    generation, last_gen,
-			    oid_to_hex(&commit->object.oid));
-		last_gen = generation;
-
-		if (generation < min_generation)
-			break;
-
 		flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 		if (flags == (PARENT1 | PARENT2)) {
 			if (!(commit->object.flags & RESULT)) {
@@ -234,7 +239,7 @@ static int paint_down_to_common(struct repository *r,
 				 */
 				if (!(mb_flags & MERGE_BASE_FIND_ALL) &&
 				    state.gen_ordered &&
-				    generation < state.topo_ceiling)
+				    state.last_gen < state.topo_ceiling)
 					break;
 			}
 			/* Mark parents of a found merge stale */
-- 
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