fix: a pull request snapshot without a file count shows none

crates/core/src/pull_request.rs

@@ -624,7 +624,9 @@ pub struct PullRequestSnapshot {
     pub additions: Option<u64>,
     #[serde(default)]
     pub deletions: Option<u64>,
-    pub changed_files: u64,
+    /// `None` where the host gave no count of changed files.
+    #[serde(default)]
+    pub changed_files: Option<u64>,
     pub review_decision: Option<ReviewDecision>,
     pub checks_state: Option<ChecksState>,
     #[serde(default)]
@@ -1765,7 +1767,7 @@ mod tests {
                 author: None,
                 additions: Some(0),
                 deletions: Some(0),
-                changed_files: 0,
+                changed_files: Some(0),
                 review_decision: None,
                 checks_state: None,
                 mergeability: Mergeability::Unknown,
@@ -1776,15 +1778,29 @@ mod tests {
         }
     }
     /// A snapshot thread metadata kept before counts could be absent still reads its counts; a
-    /// host that gives none is read as giving none, not as zero lines.
+    /// host that gives none is read as giving none, not as zero lines or files.
     #[test]
-    fn a_kept_snapshot_reads_its_line_counts() {
+    fn a_kept_snapshot_reads_its_counts() {
         let kept = r#"{"state":"open","title":"Change","head_branch":"feature","base_branch":"main","is_draft":false,"updated_at":"2026-10-08T00:00:00Z","synced_at":1,"closed_at":null,"merged_at":null,"author":null,"additions":3,"deletions":1,"changed_files":2,"review_decision":null,"checks_state":null,"mergeability":"clean"}"#;
         let snapshot: PullRequestSnapshot = serde_json::from_str(kept).unwrap();
-        assert_eq!((snapshot.additions, snapshot.deletions), (Some(3), Some(1)));
-        let uncounted = kept.replace(r#""additions":3,"deletions":1,"#, "");
+        assert_eq!(
+            (
+                snapshot.additions,
+                snapshot.deletions,
+                snapshot.changed_files
+            ),
+            (Some(3), Some(1), Some(2))
+        );
+        let uncounted = kept.replace(r#""additions":3,"deletions":1,"changed_files":2,"#, "");
         let snapshot: PullRequestSnapshot = serde_json::from_str(&uncounted).unwrap();
-        assert_eq!((snapshot.additions, snapshot.deletions), (None, None));
+        assert_eq!(
+            (
+                snapshot.additions,
+                snapshot.deletions,
+                snapshot.changed_files
+            ),
+            (None, None, None)
+        );
     }
     #[test]
     fn badge_distinguishes_unknown_drafts_terminal_and_related_links() {

crates/core/src/settlement.rs

@@ -403,7 +403,7 @@ mod tests {
                     author: None,
                     additions: Some(1),
                     deletions: Some(1),
-                    changed_files: 1,
+                    changed_files: Some(1),
                     review_decision: None,
                     checks_state: None,
                     mergeability: Mergeability::Unknown,

crates/protocol/src/lib.rs

@@ -167,6 +167,8 @@ pub use wire::{
 // SetHostToken carries an optional email.
 // Unreleased: a source-control host's kind may be azure, whose hosts are
 // organizations, dev.azure.com/{organization}.
+// Unreleased: a pull request snapshot's changed_files may be absent (null) where
+// the host counts no files.
 pub const PROTOCOL_VERSION: u32 = 10;
 
 #[cfg(test)]

crates/runtime/src/app/pull_request_watch_tests.rs

@@ -828,7 +828,7 @@ fn agent_starts_are_refused_where_the_parent_owns_the_pull_request_or_it_merged(
         author: None,
         additions: Some(0),
         deletions: Some(0),
-        changed_files: 0,
+        changed_files: Some(0),
         review_decision: None,
         checks_state: None,
         mergeability: Default::default(),

crates/services/src/azure/reads.rs

@@ -449,7 +449,7 @@ pub(super) fn snapshot(
         // Azure counts no lines; only the files read with both sides of each would.
         additions: None,
         deletions: None,
-        changed_files: 0,
+        changed_files: None,
         review_decision: review_decision(pr),
         checks_state: checks_state(checks),
         mergeability,

crates/services/src/bitbucket/reads.rs

@@ -247,7 +247,7 @@ pub(super) fn snapshot(
         // Only the diffstat counts lines, one more read per file page.
         additions: None,
         deletions: None,
-        changed_files: 0,
+        changed_files: None,
         review_decision: None,
         checks_state: checks_state(checks),
         // Conflicts are a read of their own, which the summary leaves to the detail.

crates/services/src/forgejo/reads.rs

@@ -212,7 +212,7 @@ pub(super) fn snapshot(
         }),
         additions: Some(pr["additions"].as_u64().unwrap_or(0)),
         deletions: Some(pr["deletions"].as_u64().unwrap_or(0)),
-        changed_files: pr["changed_files"].as_u64().unwrap_or(0),
+        changed_files: Some(pr["changed_files"].as_u64().unwrap_or(0)),
         review_decision: None,
         checks_state: checks,
         mergeability,

crates/services/src/github/pull_requests.rs

@@ -453,7 +453,7 @@ fn decode_summary(raw: &Value, key: &PullRequestKey) -> Option<Summary> {
             }),
             additions: Some(raw["additions"].as_u64().unwrap_or(0)),
             deletions: Some(raw["deletions"].as_u64().unwrap_or(0)),
-            changed_files: raw["changedFiles"].as_u64().unwrap_or(0),
+            changed_files: Some(raw["changedFiles"].as_u64().unwrap_or(0)),
             review_decision: review_decision(raw),
             checks_state: checks,
             mergeability: match raw["mergeable"].as_str() {

crates/services/src/gitlab/reads.rs

@@ -418,7 +418,7 @@ pub(super) fn snapshot(
         }),
         additions: stats.map(|(additions, _)| additions),
         deletions: stats.map(|(_, deletions)| deletions),
-        changed_files: changed_files(mr),
+        changed_files: Some(changed_files(mr)),
         review_decision: None,
         checks_state: checks_state(&checks(mr)),
         mergeability,

crates/ui/src/pull_requests/detail.rs

@@ -1593,16 +1593,29 @@ impl PullRequestView {
             .into()
     }
 
+    /// The Files tab's label, counted by the files read once it answers and by the snapshot
+    /// before that; a host that gives no count shows none rather than zero.
+    fn files_label(&self, cx: &App) -> String {
+        let read = self
+            .page()
+            .and_then(|page| page.files.data.as_ref())
+            .map(|files| files.changed_files);
+        let count = read.or_else(|| {
+            self.link(cx)
+                .and_then(|link| link.snapshot.as_ref().and_then(|s| s.changed_files))
+        });
+        count_label(
+            "pull_requests.detail.files",
+            "pull_requests.detail.files_count",
+            count,
+        )
+    }
+
     fn switch(&self, cx: &mut Context<Self>) -> AnyElement {
         let compact = self.compact(cx);
         let tab = self.tab(cx);
         let page = self.page();
-        let files = page.and_then(|page| page.files.data.as_ref());
         let link = self.link(cx);
-        let file_count = files.map(|files| files.changed_files).or_else(|| {
-            link.as_ref()
-                .and_then(|link| link.snapshot.as_ref().map(|s| s.changed_files))
-        });
         let conversation_count =
             page.and_then(|page| page.conversation.data.as_ref())
                 .map(|conversation| {
@@ -1615,23 +1628,11 @@ impl PullRequestView {
                         })
                         .count()
                 });
-        let label = |plain: &str, counted: &str, count: Option<u64>| match count {
-            Some(count) => crate::tr!(counted, count = count.to_string()).into_owned(),
-            None => crate::tr!(plain).into_owned(),
-        };
         let segments = [
-            (
-                "files",
-                label(
-                    "pull_requests.detail.files",
-                    "pull_requests.detail.files_count",
-                    file_count,
-                ),
-                Tab::Files,
-            ),
+            ("files", self.files_label(cx), Tab::Files),
             (
                 "conversation",
-                label(
+                count_label(
                     "pull_requests.detail.conversation",
                     "pull_requests.detail.conversation_count",
                     conversation_count.map(|count| count as u64),
@@ -1986,6 +1987,13 @@ impl Render for PullRequestView {
     }
 }
 
+fn count_label(plain: &str, counted: &str, count: Option<u64>) -> String {
+    match count {
+        Some(count) => crate::tr!(counted, count = count.to_string()).into_owned(),
+        None => crate::tr!(plain).into_owned(),
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -2237,6 +2245,94 @@ mod tests {
         assert!(reads(&requests).is_empty());
     }
 
+    /// A host that gives no count of changed files (Bitbucket, Azure DevOps) shows the Files tab
+    /// without a number until the files read answers with one, never "Files 0".
+    #[gpui::test]
+    fn a_snapshot_without_a_file_count_labels_the_files_tab_without_one(cx: &mut TestAppContext) {
+        let _locale_guard = crate::settings::TestLocaleGuard::acquire();
+        let Mounted {
+            view,
+            requests,
+            incoming,
+            _pump,
+            cx,
+        } = mount(cx);
+        let mut meta = tcode_core::project::SessionMeta::new(
+            agent::ProviderKind::ClaudeCode,
+            "/tmp/tcode-pr".into(),
+            None,
+        );
+        meta.id = "session".into();
+        meta.pull_requests = vec![ThreadPullRequestLink {
+            key: PullRequestKey::new("github.com", "octo/repo", 7),
+            url: "https://github.com/octo/repo/pull/7".into(),
+            source: PullRequestSource::Manual,
+            linked_at: None,
+            snapshot: Some(tcode_core::pull_request::PullRequestSnapshot {
+                state: PullRequestState::Open,
+                title: "Change".into(),
+                head_branch: "feature".into(),
+                base_branch: "main".into(),
+                is_draft: false,
+                updated_at: "2026-10-01T00:00:00Z".into(),
+                synced_at: 1,
+                closed_at: None,
+                merged_at: None,
+                author: None,
+                additions: None,
+                deletions: None,
+                changed_files: None,
+                review_decision: None,
+                checks_state: None,
+                mergeability: Mergeability::Unknown,
+            }),
+            stack: Default::default(),
+            sync_error: None,
+            watch: None,
+        }];
+        incoming
+            .try_send(
+                encode_line(&HostMessage::Event(tcode_protocol::EventEnvelope {
+                    request_id: None,
+                    topic: tcode_protocol::Topic::Index,
+                    event: tcode_protocol::ServerEvent::IndexSnapshot(
+                        tcode_protocol::IndexSnapshot {
+                            summary: Default::default(),
+                            sessions: vec![meta],
+                            projects: Vec::new(),
+                        },
+                    ),
+                }))
+                .unwrap(),
+            )
+            .unwrap();
+        settle(cx);
+        let store = view.read_with(cx, |view, _| view.store.clone());
+        store.update(cx, |store, cx| store.drain_host_events_for_test(cx));
+        settle(cx);
+        let label =
+            |cx: &mut VisualTestContext| view.read_with(cx, |view, cx| view.files_label(cx));
+        assert_eq!(label(cx), "Files");
+
+        let later = now() + 3600;
+        let (id, _) = reads(&requests)
+            .into_iter()
+            .find(|(_, read)| *read == PullRequestRead::Files { cursor: None })
+            .expect("the first page of files is read");
+        answer(
+            &incoming,
+            id,
+            PullRequestReadResponse::Files(files(0..3, None)),
+            later,
+        );
+        settle(cx);
+        assert_eq!(
+            label(cx),
+            "Files 150",
+            "the files read's count once it answers"
+        );
+    }
+
     #[gpui::test]
     fn switching_language_relocalizes_the_file_filter_placeholder(cx: &mut TestAppContext) {
         let _locale_guard = crate::settings::TestLocaleGuard::acquire();