cli: add test of jj debug reindex, do full reindexing

I broke the commands in a27da7d8d5 and thought I just fixed it in
c7cf914694a8. However, as I added a test, I realized that I made it
only reindex the commits since the previous operation. I meant for the
command to do a full reindexing of th repo. This fixes that.

lib/src/default_index_store.rs

@@ -66,9 +66,10 @@ impl DefaultIndexStore {
         }
     }
 
-    pub fn reinit(&self, op_id: &OperationId) {
-        let op_id_file = self.dir.join("operations").join(op_id.hex());
-        std::fs::remove_file(op_id_file).unwrap();
+    pub fn reinit(&self) {
+        let op_dir = self.dir.join("operations");
+        std::fs::remove_dir_all(&op_dir).unwrap();
+        std::fs::create_dir(op_dir).unwrap();
     }
 
     fn load_index_at_operation(

src/commands/mod.rs

@@ -3110,9 +3110,8 @@ fn cmd_debug(
             let default_index_store: Option<&DefaultIndexStore> =
                 repo.index_store().as_any().downcast_ref();
             if let Some(default_index_store) = default_index_store {
-                let op = repo.operation();
-                default_index_store.reinit(op.id());
-                let repo = repo.reload_at(op);
+                default_index_store.reinit();
+                let repo = repo.reload_at(repo.operation());
                 writeln!(
                     ui,
                     "Finished indexing {:?} commits.",

tests/test_debug_command.rs

@@ -13,6 +13,7 @@
 // limitations under the License.
 
 use insta::assert_snapshot;
+use regex::Regex;
 
 use crate::common::TestEnvironment;
 
@@ -44,21 +45,63 @@ fn test_debug_index() {
     test_env.jj_cmd_success(test_env.env_root(), &["init", "repo", "--git"]);
     let workspace_path = test_env.env_root().join("repo");
     let stdout = test_env.jj_cmd_success(&workspace_path, &["debug", "index"]);
-    insta::with_settings!(
-    {filters => vec![
-        (r"    Name: [0-9a-z]+", "    Name: [hash]"),
-    ]},
-    {
-        assert_snapshot!(stdout, @r###"
+    assert_snapshot!(filter_index_stats(&stdout), @r###"
+    Number of commits: 2
+    Number of merges: 0
+    Max generation number: 1
+    Number of heads: 1
+    Number of changes: 2
+    Stats per level:
+      Level 0:
         Number of commits: 2
-        Number of merges: 0
-        Max generation number: 1
-        Number of heads: 1
-        Number of changes: 2
-        Stats per level:
-          Level 0:
-            Number of commits: 2
-            Name: [hash]
-        "###)
-    });
+        Name: [hash]
+    "###
+    );
+}
+
+#[test]
+fn test_debug_reindex() {
+    let test_env = TestEnvironment::default();
+    test_env.jj_cmd_success(test_env.env_root(), &["init", "repo", "--git"]);
+    let workspace_path = test_env.env_root().join("repo");
+    test_env.jj_cmd_success(&workspace_path, &["new"]);
+    test_env.jj_cmd_success(&workspace_path, &["new"]);
+    let stdout = test_env.jj_cmd_success(&workspace_path, &["debug", "index"]);
+    assert_snapshot!(filter_index_stats(&stdout), @r###"
+    Number of commits: 4
+    Number of merges: 0
+    Max generation number: 3
+    Number of heads: 1
+    Number of changes: 4
+    Stats per level:
+      Level 0:
+        Number of commits: 3
+        Name: [hash]
+      Level 1:
+        Number of commits: 1
+        Name: [hash]
+    "###
+    );
+    let stdout = test_env.jj_cmd_success(&workspace_path, &["debug", "reindex"]);
+    assert_snapshot!(stdout, @r###"
+    Finished indexing 4 commits.
+    "###);
+    let stdout = test_env.jj_cmd_success(&workspace_path, &["debug", "index"]);
+    assert_snapshot!(filter_index_stats(&stdout), @r###"
+    Number of commits: 4
+    Number of merges: 0
+    Max generation number: 3
+    Number of heads: 1
+    Number of changes: 4
+    Stats per level:
+      Level 0:
+        Number of commits: 4
+        Name: [hash]
+    "###
+    );
+}
+
+fn filter_index_stats(text: &str) -> String {
+    let regex = Regex::new(r"    Name: [0-9a-z]+").unwrap();
+    regex.replace_all(text, "    Name: [hash]").to_string()
 }