Make external session detection limits configurable (#34449)

## What changed

- Add `maxSessionAgeDays` and `maxSessions` to the external-agent config detection request.
- Apply the requested limits when discovering sessions from supported migration sources.
- Preserve the existing defaults of a 30-day maximum age and 50 sessions when either option is omitted.

GitOrigin-RevId: 46376e94b64f1f61d8776e34d82cdd2cdeb36ca0

codex-rs/external-agent-migration/src/detect/mod.rs

@@ -378,9 +378,11 @@ impl ExternalAgentConfigService {
         }
 
         if scope.is_home() {
-            let sessions = self
-                .source
-                .recent_sessions(&self.external_agent_home, &self.codex_home)?;
+            let sessions = self.source.recent_sessions(
+                &self.external_agent_home,
+                &self.codex_home,
+                self.session_import_limits,
+            )?;
             if !sessions.is_empty() {
                 items.push(ExternalAgentConfigMigrationItem {
                     item_type: ExternalAgentConfigMigrationItemType::Sessions,

codex-rs/external-agent-migration/src/detect/sessions/cla.rs

@@ -1,7 +1,6 @@
-#[cfg(test)]
-use super::common::SESSION_IMPORT_MAX_COUNT;
 use super::common::SessionFileCandidate;
 use super::common::detect_recent_sessions;
+use crate::model::ExternalAgentSessionImportLimits;
 use crate::sessions::ExternalAgentSessionMigration;
 use std::fs;
 use std::io;
@@ -10,6 +9,18 @@ use std::path::Path;
 pub fn detect_recent_cla_sessions(
     external_agent_home: &Path,
     codex_home: &Path,
+) -> io::Result<Vec<ExternalAgentSessionMigration>> {
+    detect_recent_cla_sessions_with_limits(
+        external_agent_home,
+        codex_home,
+        ExternalAgentSessionImportLimits::default(),
+    )
+}
+
+pub(crate) fn detect_recent_cla_sessions_with_limits(
+    external_agent_home: &Path,
+    codex_home: &Path,
+    limits: ExternalAgentSessionImportLimits,
 ) -> io::Result<Vec<ExternalAgentSessionMigration>> {
     let projects_root = external_agent_home.join("projects");
     if !projects_root.is_dir() {
@@ -42,7 +53,9 @@ pub fn detect_recent_cla_sessions(
             });
         }
     }
-    detect_recent_sessions(codex_home, candidates, /*require_existing_cwd*/ true)
+    detect_recent_sessions(
+        codex_home, candidates, /*require_existing_cwd*/ true, limits,
+    )
 }
 
 #[cfg(test)]
@@ -233,7 +246,8 @@ mod tests {
         let timestamp = chrono::Utc::now().to_rfc3339_opts(chrono::SecondsFormat::Secs, true);
         let modified_at = SystemTime::now();
         let mut expected = Vec::new();
-        for index in 0..=SESSION_IMPORT_MAX_COUNT {
+        let default_limits = ExternalAgentSessionImportLimits::default();
+        for index in 0..=default_limits.max_sessions {
             let file_name = format!("{index:02}-session.jsonl");
             let title = format!("session {index}");
             let path = write_session(
@@ -275,7 +289,7 @@ mod tests {
         }
 
         let changed_at = SystemTime::now()
-            + Duration::from_secs(/*secs*/ SESSION_IMPORT_MAX_COUNT as u64 + 1);
+            + Duration::from_secs(/*secs*/ default_limits.max_sessions as u64 + 1);
         for (index, session) in all_sessions.iter().enumerate() {
             let title = session.title.as_deref().expect("session title");
             std::fs::write(

codex-rs/external-agent-migration/src/detect/sessions/common.rs

@@ -1,3 +1,4 @@
+use crate::model::ExternalAgentSessionImportLimits;
 use crate::sessions::ExternalAgentSessionMigration;
 use crate::sessions::ledger::load_import_ledger;
 use crate::sessions::ledger::save_import_ledger;
@@ -9,10 +10,6 @@ use std::fs;
 use std::io;
 use std::path::Path;
 use std::path::PathBuf;
-use std::time::Duration;
-
-pub(super) const SESSION_IMPORT_MAX_COUNT: usize = 50;
-const SESSION_IMPORT_MAX_AGE: Duration = Duration::from_secs(30 * 24 * 60 * 60);
 
 pub(super) struct SessionFileCandidate {
     pub path: PathBuf,
@@ -23,11 +20,12 @@ pub(super) fn detect_recent_sessions(
     codex_home: &Path,
     candidates: impl IntoIterator<Item = SessionFileCandidate>,
     require_existing_cwd: bool,
+    limits: ExternalAgentSessionImportLimits,
 ) -> io::Result<Vec<ExternalAgentSessionMigration>> {
     let now = now_unix_seconds();
     let mut ledger = load_import_ledger(codex_home)?;
     let source_states = ledger.source_states();
-    let mut recent = BinaryHeap::with_capacity(SESSION_IMPORT_MAX_COUNT + 1);
+    let mut recent = BinaryHeap::new();
 
     for candidate in candidates {
         let Ok(metadata) = fs::metadata(&candidate.path) else {
@@ -39,9 +37,7 @@ pub(super) fn detect_recent_sessions(
         let Ok(modified_at) = modified_at.duration_since(std::time::UNIX_EPOCH) else {
             continue;
         };
-        if (modified_at.as_secs() as i64)
-            < now.saturating_sub(SESSION_IMPORT_MAX_AGE.as_secs() as i64)
-        {
+        if (modified_at.as_secs() as i64) < now.saturating_sub(limits.max_age.as_secs() as i64) {
             continue;
         }
         let Ok(modified_at_nanos) = i64::try_from(modified_at.as_nanos()) else {
@@ -62,7 +58,7 @@ pub(super) fn detect_recent_sessions(
             candidate.path,
             candidate.fallback_cwd,
         ));
-        if recent.len() > SESSION_IMPORT_MAX_COUNT {
+        if recent.len() > limits.max_sessions {
             recent.pop();
         }
     }

codex-rs/external-agent-migration/src/detect/sessions/cur.rs

@@ -1,7 +1,6 @@
-#[cfg(test)]
-use super::common::SESSION_IMPORT_MAX_COUNT;
 use super::common::SessionFileCandidate;
 use super::common::detect_recent_sessions;
+use crate::model::ExternalAgentSessionImportLimits;
 use crate::sessions::ExternalAgentSessionMigration;
 use std::fs;
 use std::io;
@@ -11,6 +10,18 @@ use std::path::PathBuf;
 pub fn detect_recent_cur_sessions(
     external_agent_home: &Path,
     codex_home: &Path,
+) -> io::Result<Vec<ExternalAgentSessionMigration>> {
+    detect_recent_cur_sessions_with_limits(
+        external_agent_home,
+        codex_home,
+        ExternalAgentSessionImportLimits::default(),
+    )
+}
+
+pub(crate) fn detect_recent_cur_sessions_with_limits(
+    external_agent_home: &Path,
+    codex_home: &Path,
+    limits: ExternalAgentSessionImportLimits,
 ) -> io::Result<Vec<ExternalAgentSessionMigration>> {
     let projects_root = external_agent_home.join("projects");
     if !projects_root.is_dir() {
@@ -34,7 +45,9 @@ pub fn detect_recent_cur_sessions(
             });
         }
     }
-    detect_recent_sessions(codex_home, candidates, /*require_existing_cwd*/ false)
+    detect_recent_sessions(
+        codex_home, candidates, /*require_existing_cwd*/ false, limits,
+    )
 }
 
 fn cur_transcript_files(transcripts_root: &Path) -> Vec<PathBuf> {

codex-rs/external-agent-migration/src/detect/sessions/cur_tests.rs

@@ -171,7 +171,8 @@ fn detects_cur_sessions_in_batches_and_redetects_modified_imports() {
     let encoded_project = encode_project_path(&project_root);
     let modified_at = SystemTime::now();
     let mut expected = Vec::new();
-    for index in 0..=SESSION_IMPORT_MAX_COUNT {
+    let default_limits = ExternalAgentSessionImportLimits::default();
+    for index in 0..=default_limits.max_sessions {
         let session_id = format!("session-{index:02}");
         let title = format!("request {index}");
         let path = write_transcript(&external_agent_home, &encoded_project, &session_id, &title);

codex-rs/external-agent-migration/src/detect/sessions/mod.rs

@@ -4,6 +4,8 @@ mod connectors_cla;
 mod cur;
 
 pub use cla::detect_recent_cla_sessions;
+pub(crate) use cla::detect_recent_cla_sessions_with_limits;
 pub use connectors_cla::ImportedSessionConnectorAttribution;
 pub use connectors_cla::detect_imported_cla_session_connectors;
 pub use cur::detect_recent_cur_sessions;
+pub(crate) use cur::detect_recent_cur_sessions_with_limits;