cli: keep cached SSH terminfo installs current (#13844)

On a local cache miss, always send our embedded terminfo source to the
remote `tic` instead of accepting any existing entry reported by
`infocmp`.

We also version cache entries using a content-derived hash of our
embedded terminfo. Non-matching entries produce a cache miss and trigger
(re)installation.

src/cli/ssh-cache/DiskCache.zig

@@ -58,6 +58,7 @@ pub fn add(
     self: DiskCache,
     alloc: Allocator,
     key: []const u8,
+    version: []const u8,
     timestamp: i64,
 ) !void {
     if (!isValidCacheKey(key)) return error.InvalidCacheKey;
@@ -111,16 +112,19 @@ pub fn add(
     // `deinitEntries` defer to walk.
     if (entries.getPtr(key)) |existing| {
         existing.timestamp = timestamp;
+        const version_copy = try alloc.dupe(u8, version);
+        alloc.free(existing.terminfo_version);
+        existing.terminfo_version = version_copy;
     } else {
         const key_copy = try alloc.dupe(u8, key);
         errdefer alloc.free(key_copy);
-        const terminfo_copy = try alloc.dupe(u8, "xterm-ghostty");
-        errdefer alloc.free(terminfo_copy);
+        const version_copy = try alloc.dupe(u8, version);
+        errdefer alloc.free(version_copy);
 
         try entries.put(key_copy, .{
             .hostname = key_copy,
             .timestamp = timestamp,
-            .terminfo_version = terminfo_copy,
+            .terminfo_version = version_copy,
         });
     }
 
@@ -225,12 +229,13 @@ pub fn prune(
     return expired.items.len;
 }
 
-/// Check if a key exists in the cache.
-/// Returns false if the cache file doesn't exist.
+/// Check if a key with `version` exists in the cache.
+/// Returns false if the cache file doesn't exist or the version doesn't match.
 pub fn contains(
     self: DiskCache,
     alloc: Allocator,
     key: []const u8,
+    version: []const u8,
 ) !bool {
     if (!isValidCacheKey(key)) return error.InvalidCacheKey;
 
@@ -249,7 +254,8 @@ pub fn contains(
     var entries = try readEntries(alloc, file);
     defer deinitEntries(alloc, &entries);
 
-    return entries.contains(key);
+    const entry = entries.get(key) orelse return false;
+    return std.mem.eql(u8, entry.terminfo_version, version);
 }
 
 fn fixupPermissions(file: std.Io.File) !void {
@@ -506,20 +512,25 @@ test "disk cache operations" {
     // Setup our cache. Adding the same key twice exercises both the new
     // and existing-entry paths.
     const cache: DiskCache = .{ .path = path };
-    try cache.add(alloc, "example.com", std.Io.Timestamp.now(testing.io, .real).toSeconds());
-    try cache.add(alloc, "example.com", std.Io.Timestamp.now(testing.io, .real).toSeconds());
-    try testing.expect(try cache.contains(alloc, "example.com"));
+    try cache.add(alloc, "example.com", "v1", std.Io.Timestamp.now(testing.io, .real).toSeconds());
+    try testing.expect(!try cache.contains(alloc, "example.com", "v2"));
+    try cache.add(alloc, "example.com", "v2", std.Io.Timestamp.now(testing.io, .real).toSeconds());
+    try testing.expect(try cache.contains(alloc, "example.com", "v2"));
 
     // List
     var entries = try cache.list(alloc);
-    deinitEntries(alloc, &entries);
+    defer deinitEntries(alloc, &entries);
+    try testing.expectEqualStrings(
+        "v2",
+        entries.get("example.com").?.terminfo_version,
+    );
 
     // Remove reports that it removed the entry, and a second remove of the
     // same key reports nothing to remove.
     try testing.expect(try cache.remove(alloc, "example.com"));
     try testing.expect(!try cache.remove(alloc, "example.com"));
-    try testing.expect(!(try cache.contains(alloc, "example.com")));
-    try cache.add(alloc, "example.com", std.Io.Timestamp.now(testing.io, .real).toSeconds());
+    try testing.expect(!(try cache.contains(alloc, "example.com", "v2")));
+    try cache.add(alloc, "example.com", "v2", std.Io.Timestamp.now(testing.io, .real).toSeconds());
 }
 
 test "disk cache cleans up temp files" {
@@ -535,8 +546,8 @@ test "disk cache cleans up temp files" {
     defer alloc.free(cache_path);
 
     const cache: DiskCache = .{ .path = cache_path };
-    try cache.add(alloc, "example.com", std.Io.Timestamp.now(testing.io, .real).toSeconds());
-    try cache.add(alloc, "example.org", std.Io.Timestamp.now(testing.io, .real).toSeconds());
+    try cache.add(alloc, "example.com", "v1", std.Io.Timestamp.now(testing.io, .real).toSeconds());
+    try cache.add(alloc, "example.org", "v1", std.Io.Timestamp.now(testing.io, .real).toSeconds());
 
     // Verify only the cache file exists and no temp files left behind
     var count: usize = 0;
@@ -566,20 +577,20 @@ test "disk cache prune" {
     const day = std.time.s_per_day;
     const hour = std.time.s_per_hour;
     const now = std.Io.Timestamp.now(testing.io, .real).toSeconds();
-    try cache.add(alloc, "recent.com", now - hour);
-    try cache.add(alloc, "old.com", now - 100 * day);
+    try cache.add(alloc, "recent.com", "v1", now - hour);
+    try cache.add(alloc, "old.com", "v1", now - 100 * day);
 
     // Prune entries older than 90 days: only old.com goes.
     try testing.expectEqual(@as(usize, 1), try cache.prune(alloc, 90 * day));
-    try testing.expect(try cache.contains(alloc, "recent.com"));
-    try testing.expect(!try cache.contains(alloc, "old.com"));
+    try testing.expect(try cache.contains(alloc, "recent.com", "v1"));
+    try testing.expect(!try cache.contains(alloc, "old.com", "v1"));
 
     // Pruning again removes nothing.
     try testing.expectEqual(@as(usize, 0), try cache.prune(alloc, 90 * day));
 
     // Sub-day granularity: a 30-minute max age prunes the hour-old entry.
     try testing.expectEqual(@as(usize, 1), try cache.prune(alloc, 30 * std.time.s_per_min));
-    try testing.expect(!try cache.contains(alloc, "recent.com"));
+    try testing.expect(!try cache.contains(alloc, "recent.com", "v1"));
 }
 
 test "disk cache prune missing file" {
@@ -707,7 +718,7 @@ test "disk cache add survives allocation failure" {
         );
         const alloc = failing.allocator();
 
-        if (cache.add(alloc, "user@example.com", 100)) |_| {
+        if (cache.add(alloc, "user@example.com", "v1", 100)) |_| {
             if (!failing.has_induced_failure) break;
         } else |err| {
             try testing.expectEqual(error.OutOfMemory, err);

src/cli/ssh.zig

@@ -7,7 +7,7 @@ const diagnostics = @import("diagnostics.zig");
 const Action = @import("ghostty.zig").Action;
 const DiskCache = @import("ssh_cache.zig").DiskCache;
 const internal_os = @import("../os/main.zig");
-const ghostty_terminfo = @import("../terminfo/main.zig").ghostty;
+const terminfopkg = @import("../terminfo/main.zig");
 const global = @import("../global.zig");
 
 const log = std.log.scoped(.ssh);
@@ -128,9 +128,9 @@ pub const Options = struct {
 ///      forwarding to succeed.
 ///
 ///   2. **Terminfo install** (`--terminfo`). On the first connection to a
-///      given destination, installs Ghostty's terminfo entry on the remote
-///      host using `infocmp -x xterm-ghostty | ssh tic -x -` over a
-///      shared `ControlMaster` connection. Successful installs are cached
+///      given destination, installs Ghostty's embedded terminfo entry on the
+///      remote host using `ssh tic -x -` over a shared `ControlMaster`
+///      connection. Successful installs are cached
 ///      (see `ghostty +ssh-cache`) so subsequent connections skip this
 ///      step. When terminfo is successfully installed or already cached,
 ///      `TERM` is set to `xterm-ghostty` instead of `xterm-256color`.
@@ -252,7 +252,11 @@ fn runInner(
         } else null;
 
         if (cache) |c| {
-            const cached = c.contains(alloc, dest) catch |err| cached: {
+            const cached = c.contains(
+                alloc,
+                dest,
+                terminfopkg.version,
+            ) catch |err| cached: {
                 if (DiskCache.isFailure(err)) warnPrint(
                     stderr,
                     "unable to read the cache '{s}': {t}",
@@ -313,10 +317,12 @@ fn runInner(
 
     // Attempt to cache (if needed) on a successful ssh execution.
     if (exit_code == 0) if (session.to_cache) |entry| {
-        if (entry.cache.add(alloc, entry.dest, std.Io.Timestamp.now(
-            global.io(),
-            .real,
-        ).toSeconds())) |_| {
+        if (entry.cache.add(
+            alloc,
+            entry.dest,
+            terminfopkg.version,
+            std.Io.Timestamp.now(global.io(), .real).toSeconds(),
+        )) |_| {
             verbosePrint(opts, stderr, "cache: wrote {s}", .{entry.dest});
         } else |err| {
             if (DiskCache.isFailure(err)) {
@@ -473,7 +479,7 @@ fn installRemoteTerminfo(
 ) !void {
     var buf: std.Io.Writer.Allocating = .init(alloc);
     defer buf.deinit();
-    try ghostty_terminfo.encode(&buf.writer);
+    try terminfopkg.ghostty.encode(&buf.writer);
     const terminfo = buf.written();
 
     // ControlPath is in TMPDIR with a short, random basename. ssh uses
@@ -491,20 +497,17 @@ fn installRemoteTerminfo(
     // the most common failure source) and inherit ssh's stderr so it
     // reaches the user's terminal. Other steps stay quiet either way.
     const remote_script = if (opts.verbose)
-        \\infocmp xterm-ghostty >/dev/null 2>&1 && exit 0
         \\command -v tic >/dev/null 2>&1 || exit 1
         \\mkdir -p ~/.terminfo 2>/dev/null && tic -x - && exit 0
         \\exit 1
     else
-        \\infocmp xterm-ghostty >/dev/null 2>&1 && exit 0
         \\command -v tic >/dev/null 2>&1 || exit 1
         \\mkdir -p ~/.terminfo 2>/dev/null && tic -x - 2>/dev/null && exit 0
         \\exit 1
     ;
 
     // Set up an SSH ControlMaster scoped to this single install:
-    //   - ControlMaster=yes makes our client also act as the master,
-    //     so `infocmp | ssh tic` runs over a single connection.
+    //   - ControlMaster=yes makes our client also act as the master.
     //   - ControlPersist=no tears the master down when our client
     //     exits; no socket lingers on the remote side.
     const argv = try std.mem.concat(alloc, []const u8, &.{

src/cli/ssh_cache.zig

@@ -5,6 +5,7 @@ const args = @import("args.zig");
 const global = @import("../global.zig");
 const Action = @import("ghostty.zig").Action;
 const Duration = @import("../config.zig").Config.Duration;
+const terminfopkg = @import("../terminfo/main.zig");
 pub const Entry = @import("ssh-cache/Entry.zig");
 pub const DiskCache = @import("ssh-cache/DiskCache.zig");
 
@@ -198,6 +199,7 @@ pub fn runInner(
         cache.add(
             alloc,
             dest,
+            terminfopkg.version,
             std.Io.Timestamp.now(global.io(), .real).toSeconds(),
         ) catch |err| switch (err) {
             error.InvalidCacheKey => {

src/config/Config.zig

@@ -2931,10 +2931,9 @@ keybind: Keybinds = .{},
 ///     (Available since: 1.2.0)
 ///
 ///   * `ssh-terminfo` - Enable automatic terminfo installation on remote hosts.
-///     Attempts to install Ghostty's terminfo entry using `infocmp` and `tic` when
-///     connecting to hosts that lack it. Requires `infocmp` to be available locally
-///     and `tic` to be available on remote hosts. Once terminfo is installed on a
-///     remote host, it will be automatically "cached" to avoid repeat installations.
+///     Attempts to install Ghostty's embedded terminfo entry using `tic` on local
+///     cache misses. Requires `tic` to be available on remote hosts. Successful
+///     installations are cached locally to avoid repeat installations.
 ///     If desired, the `+ssh-cache` CLI action can be used to manage the installation
 ///     cache manually using various arguments.
 ///     (Available since: 1.2.0)

src/terminfo/ghostty.zig

@@ -392,6 +392,15 @@ pub const ghostty: Source = .{
     },
 };
 
+/// A content-derived version of the encoded terminfo source.
+pub const version = version: {
+    @setEvalBranchQuota(100_000);
+    var hashing: std.Io.Writer.Hashing(std.hash.Wyhash) =
+        .initHasher(.init(0), &.{});
+    ghostty.encode(&hashing.writer) catch unreachable;
+    break :version std.fmt.comptimePrint("{x}", .{hashing.hasher.final()});
+};
+
 test "encode" {
     // Encode
     var buf: [1024 * 16]u8 = undefined;

src/terminfo/main.zig

@@ -6,6 +6,7 @@
 //! extract this into a more full-featured library on its own.
 
 pub const ghostty = @import("ghostty.zig").ghostty;
+pub const version = @import("ghostty.zig").version;
 pub const Source = @import("Source.zig");
 
 test {