From 5893b52fd16e5950536698c6a667f37675d081cd Mon Sep 17 00:00:00 2001
From: Martin von Zweigbergk <martinvonz@google.com>
Date: Sat, 30 Apr 2022 22:55:58 -0700
Subject: [PATCH] cleanup: use `while let Some(...)` instead of checking before
 popping

---
 lib/src/dag_walk.rs     | 3 +--
 lib/src/index.rs        | 9 +++------
 lib/src/index_store.rs  | 6 ++----
 lib/src/working_copy.rs | 3 +--
 src/commands.rs         | 3 +--
 5 files changed, 8 insertions(+), 16 deletions(-)

diff --git a/lib/src/dag_walk.rs b/lib/src/dag_walk.rs
index 405022dd8..7de2159fe 100644
--- a/lib/src/dag_walk.rs
+++ b/lib/src/dag_walk.rs
@@ -87,8 +87,7 @@ where
 
     for start_node in start_nodes {
         let mut stack = vec![(start_node, false)];
-        while !stack.is_empty() {
-            let (node, neighbors_visited) = stack.pop().unwrap();
+        while let Some((node, neighbors_visited)) = stack.pop() {
             let id = id_fn(&node);
             if emitted.contains(&id) {
                 continue;
diff --git a/lib/src/index.rs b/lib/src/index.rs
index bbf396658..c97e37e5a 100644
--- a/lib/src/index.rs
+++ b/lib/src/index.rs
@@ -763,8 +763,7 @@ impl<'a> CompositeIndex<'a> {
         let ancestor_generation = self.entry_by_pos(ancestor_pos).generation_number();
         let mut work = vec![descendant_pos];
         let mut visited = HashSet::new();
-        while !work.is_empty() {
-            let descendant_pos = work.pop().unwrap();
+        while let Some(descendant_pos) = work.pop() {
             let descendant_entry = self.entry_by_pos(descendant_pos);
             if descendant_pos == ancestor_pos {
                 return true;
@@ -889,8 +888,7 @@ impl<'a> CompositeIndex<'a> {
         // set of candidates. Stop walking when we have gone past the minimum
         // candidate generation.
         let mut visited = HashSet::new();
-        while !work.is_empty() {
-            let item = work.pop().unwrap().0;
+        while let Some(IndexEntryByGeneration(item)) = work.pop() {
             if !visited.insert(item.pos) {
                 continue;
             }
@@ -1017,8 +1015,7 @@ impl<'a> Iterator for RevWalk<'a> {
     type Item = IndexEntry<'a>;
 
     fn next(&mut self) -> Option<Self::Item> {
-        while !self.wanted_boundary_set.is_empty() {
-            let item = self.items.pop().unwrap();
+        while let Some(item) = self.items.pop() {
             if item.wanted {
                 self.wanted_boundary_set.remove(&item.entry.0.pos);
                 if self.unwanted_boundary_set.contains(&item.entry.0.pos) {
diff --git a/lib/src/index_store.rs b/lib/src/index_store.rs
index 00965696e..2d07e2283 100644
--- a/lib/src/index_store.rs
+++ b/lib/src/index_store.rs
@@ -187,8 +187,7 @@ fn topo_order_earlier_first(
     let mut visited = HashSet::new();
     let mut in_parent_file = HashSet::new();
     let parent_file_source = parent_file.as_ref().map(|file| file.as_ref());
-    while !work.is_empty() {
-        let commit = work.pop().unwrap();
+    while let Some(commit) = work.pop() {
         if parent_file_source.map_or(false, |index| index.has_id(commit.id())) {
             in_parent_file.insert(commit.id().clone());
             continue;
@@ -213,8 +212,7 @@ fn topo_order_earlier_first(
 
     let mut result = vec![];
     let mut visited = in_parent_file;
-    while !commits.is_empty() {
-        let commit = commits.pop().unwrap();
+    while let Some(commit) = commits.pop() {
         let mut waiting_for_earlier_commit = false;
         for earlier in commit.parents().iter().chain(commit.predecessors().iter()) {
             if !visited.contains(earlier.id()) {
diff --git a/lib/src/working_copy.rs b/lib/src/working_copy.rs
index 6de403974..e367a4a5e 100644
--- a/lib/src/working_copy.rs
+++ b/lib/src/working_copy.rs
@@ -335,8 +335,7 @@ impl TreeState {
         )];
         let mut tree_builder = self.store.tree_builder(self.tree_id.clone());
         let mut deleted_files: HashSet<_> = self.file_states.keys().cloned().collect();
-        while !work.is_empty() {
-            let (dir, disk_dir, git_ignore) = work.pop().unwrap();
+        while let Some((dir, disk_dir, git_ignore)) = work.pop() {
             if sparse_matcher.visit(&dir).is_nothing() {
                 continue;
             }
diff --git a/src/commands.rs b/src/commands.rs
index 9188df48d..dfc2188d5 100644
--- a/src/commands.rs
+++ b/src/commands.rs
@@ -864,8 +864,7 @@ fn find_all_operations(
     let mut visited = HashSet::new();
     let mut work: VecDeque<_> = op_heads_store.get_op_heads().into_iter().collect();
     let mut operations = vec![];
-    while !work.is_empty() {
-        let op_id = work.pop_front().unwrap();
+    while let Some(op_id) = work.pop_front() {
         if visited.insert(op_id.clone()) {
             let store_operation = op_store.read_operation(&op_id).unwrap();
             work.extend(store_operation.parents.iter().cloned());