Merge pull request #331 from dignfei/fix/shell-history-performance

fix(terminal): bound shell history replay

src/tmux-manager.ts

@@ -1568,6 +1568,8 @@ export class TmuxManager extends EventEmitter implements TerminalMultiplexer {
   private reconnectGuard: Set<string> = new Set();
 
   private trueColorConfigured = false;
+  /** tmux 3.7+ can resize pane history after creation; older releases cannot. */
+  private liveHistoryResizeSupported: boolean | null = null;
 
   constructor() {
     super();
@@ -1586,6 +1588,26 @@ export class TmuxManager extends EventEmitter implements TerminalMultiplexer {
     return tmuxCommand(this.tmuxSocket);
   }
 
+  private supportsLiveHistoryResize(): boolean {
+    if (this.liveHistoryResizeSupported !== null) return this.liveHistoryResizeSupported;
+
+    try {
+      const output = execSync(`${this.tmux()} -V`, {
+        encoding: 'utf8',
+        timeout: EXEC_TIMEOUT_MS,
+        stdio: ['ignore', 'pipe', 'ignore'],
+      });
+      const match = output.match(/(?:^|\D)(\d+)\.(\d+)/);
+      const major = match ? Number(match[1]) : 0;
+      const minor = match ? Number(match[2]) : 0;
+      this.liveHistoryResizeSupported = major > 3 || (major === 3 && minor >= 7);
+    } catch {
+      // Unknown versions take the legacy path required by tmux <3.7.
+      this.liveHistoryResizeSupported = false;
+    }
+    return this.liveHistoryResizeSupported;
+  }
+
   // Load saved sessions from disk (NEVER called in test mode)
   private loadSessions(): void {
     if (IS_TEST_MODE) return;
@@ -1926,7 +1948,16 @@ export class TmuxManager extends EventEmitter implements TerminalMultiplexer {
       // launched in TMUX_LAUNCH_CWD (/tmp) rather than the real workingDir: a FUSE/rclone
       // mount that isn't ready yet makes `getcwd` fail and breaks the spawn (see #110). The
       // pane cd's into workingDir below via respawn-pane.
-      execSync(`${this.tmux()} new-session -ds "${muxName}" -c ${TMUX_LAUNCH_CWD}`, {
+      // tmux <3.7 allocates history only at pane creation, so its global default
+      // must be set immediately BEFORE new-session. tmux 3.7+ can resize a pane
+      // after creation; target only the new session there because changing the
+      // global option can resize (and when lowered, trim) unrelated live panes.
+      const safeHistoryLimit =
+        Number.isSafeInteger(historyLimit) && historyLimit > 0 ? Math.trunc(historyLimit) : DEFAULT_TMUX_HISTORY_LIMIT;
+      const createSessionCommand = this.supportsLiveHistoryResize()
+        ? `${this.tmux()} new-session -ds "${muxName}" -c ${TMUX_LAUNCH_CWD} \\; set-option -t "${muxName}" history-limit ${safeHistoryLimit}`
+        : `${this.tmux()} set-option -g history-limit ${safeHistoryLimit} \\; new-session -ds "${muxName}" -c ${TMUX_LAUNCH_CWD} \\; set-option -t "${muxName}" history-limit ${safeHistoryLimit}`;
+      execSync(createSessionCommand, {
         cwd: TMUX_LAUNCH_CWD,
         timeout: EXEC_TIMEOUT_MS,
         stdio: 'ignore',
@@ -1991,16 +2022,6 @@ export class TmuxManager extends EventEmitter implements TerminalMultiplexer {
           .catch(() => {
             /* Already set globally as fallback */
           }),
-        // Raise tmux scrollback from its 2000-line default so re-attach preserves
-        // more context. Intentionally exceeds the xterm-side DEFAULT_SCROLLBACK (50k
-        // in constants.js), which stays lower to protect browser/mobile memory.
-        execAsync(`${this.tmux()} set-option -t "${muxName}" history-limit ${historyLimit}`, {
-          timeout: EXEC_TIMEOUT_MS,
-        })
-          .then(() => {})
-          .catch(() => {
-            /* Non-critical — falls back to tmux default */
-          }),
       ];
 
       // Enable 24-bit true color passthrough — server-wide, set once per lifetime
@@ -2124,7 +2145,6 @@ export class TmuxManager extends EventEmitter implements TerminalMultiplexer {
       resumeSessionId,
       envOverrides,
       effort,
-      historyLimit = DEFAULT_TMUX_HISTORY_LIMIT,
       remote,
       docker,
       name,
@@ -2135,16 +2155,6 @@ export class TmuxManager extends EventEmitter implements TerminalMultiplexer {
 
     if (!isValidMuxName(muxName) || !isValidPath(workingDir)) return null;
 
-    // Re-apply the configured tmux history-limit after respawn (kept in sync
-    // with the live setting via setHistoryLimit()).
-    if (!IS_TEST_MODE) {
-      await execAsync(`${this.tmux()} set-option -t ${shellescape(muxName)} history-limit ${historyLimit}`, {
-        timeout: EXEC_TIMEOUT_MS,
-      }).catch(() => {
-        /* Non-critical — keeps existing tmux history-limit */
-      });
-    }
-
     // Resolve CLI binary directory based on mode
     const { pathExport } = this.buildPathExport(mode);
 
@@ -3003,9 +3013,9 @@ export class TmuxManager extends EventEmitter implements TerminalMultiplexer {
   }
 
   /**
-   * Apply a tmux history-limit to all tracked sessions (e.g. when the user
-   * changes the terminal-history setting). Invalid limits fall back to the
-   * default. Best-effort per session.
+   * Apply a tmux history limit. tmux 3.7+ safely targets tracked live sessions;
+   * older releases can only change the global default for future panes. Invalid
+   * limits fall back to the default.
    */
   async setHistoryLimit(limit: number): Promise<void> {
     const safeLimit = Number.isSafeInteger(limit) && limit > 0 ? Math.trunc(limit) : DEFAULT_TMUX_HISTORY_LIMIT;
@@ -3014,12 +3024,22 @@ export class TmuxManager extends EventEmitter implements TerminalMultiplexer {
       return;
     }
 
-    const updates = Array.from(this.sessions.values()).map((session) =>
-      execAsync(`${this.tmux()} set-option -t ${shellescape(session.muxName)} history-limit ${safeLimit}`, {
-        timeout: EXEC_TIMEOUT_MS,
-      })
-    );
-    await Promise.allSettled(updates);
+    if (this.supportsLiveHistoryResize()) {
+      const updates = Array.from(this.sessions.values()).map((session) =>
+        execAsync(`${this.tmux()} set-option -t ${shellescape(session.muxName)} history-limit ${safeLimit}`, {
+          timeout: EXEC_TIMEOUT_MS,
+        })
+      );
+      await Promise.allSettled(updates);
+      return;
+    }
+
+    await execAsync(`${this.tmux()} set-option -g history-limit ${safeLimit}`, {
+      timeout: EXEC_TIMEOUT_MS,
+    }).catch(() => {
+      // No tmux server yet is fine: legacy createSession sets the same default
+      // immediately before it creates the first pane.
+    });
   }
 
   /**