feat: add Oh My Pi (OMP) adapter + fix symlink path encoding on macOS

cmd/sidecar/main.go

@@ -24,6 +24,7 @@ import (
 	_ "github.com/marcus/sidecar/internal/adapter/opencode"
 	_ "github.com/marcus/sidecar/internal/adapter/pi"
 	_ "github.com/marcus/sidecar/internal/adapter/piagent"
+	_ "github.com/marcus/sidecar/internal/adapter/omp"
 	_ "github.com/marcus/sidecar/internal/adapter/warp"
 	"github.com/marcus/sidecar/internal/app"
 	"github.com/marcus/sidecar/internal/config"

internal/adapter/omp/doc.go

@@ -0,0 +1,6 @@
+// Package omp implements an adapter for Oh My Pi (OMP) agent sessions.
+//
+// OMP is a fork of Pi Agent and uses the same JSONL format. Sessions are stored
+// in ~/.omp/agent/sessions/<encoded-path>/ where encoded-path is the project
+// path with slashes replaced by dashes, wrapped in double dashes.
+package omp

internal/adapter/omp/register.go

@@ -0,0 +1,80 @@
+package omp
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/marcus/sidecar/internal/adapter"
+	"github.com/marcus/sidecar/internal/adapter/piagent"
+)
+
+func init() {
+	adapter.RegisterFactory(func() adapter.Adapter {
+		home, _ := os.UserHomeDir()
+		sessionsDir := filepath.Join(home, ".omp", "agent", "sessions")
+		return piagent.NewCustom(sessionsDir, "omp", "OMP", "Ω").
+			WithProjectDirFunc(projectDirPath)
+	})
+}
+
+// projectDirPath implements OMP's session directory encoding.
+//
+// OMP v15+ uses a home-relative encoding for paths within the user's home
+// directory, a tmpdir-relative encoding for paths within the temp directory,
+// and falls back to the legacy absolute encoding (--path-encoded--) for
+// everything else. Old sessions created before the encoding change retain
+// the legacy name; OMP migrates home-relative sessions automatically but
+// leaves tmp sessions in place.
+//
+// Encoding rules (after symlink resolution and macOS /private stripping):
+//   - within home:   -<relative-path-with-slashes-as-dashes>
+//   - within tmpdir: -tmp-<relative-path-with-slashes-as-dashes>  (or -tmp if cwd==tmpdir)
+//   - elsewhere:     --<abs-path-with-slashes-as-dashes>--  (legacy)
+func projectDirPath(sessionsDir, projectRoot string) string {
+	cwd, err := filepath.Abs(projectRoot)
+	if err != nil {
+		cwd = projectRoot
+	}
+	if resolved, err := filepath.EvalSymlinks(cwd); err == nil {
+		cwd = resolved
+	}
+	// On macOS, strip the /private prefix that EvalSymlinks adds for /tmp etc.
+	// OMP does this to keep paths like /tmp stable across symlink resolution.
+	if strings.HasPrefix(cwd, "/private/") {
+		stripped := cwd[len("/private"):]
+		if sr, err := filepath.EvalSymlinks(stripped); err == nil && sr == cwd {
+			cwd = stripped
+		}
+	}
+
+	home, _ := os.UserHomeDir()
+	if resolved, err := filepath.EvalSymlinks(home); err == nil {
+		home = resolved
+	}
+	tmpdir := os.TempDir() // returns /tmp on macOS (already without /private)
+
+	switch {
+	case cwd == home || strings.HasPrefix(cwd, home+string(filepath.Separator)):
+		rel, _ := filepath.Rel(home, cwd)
+		encoded := strings.ReplaceAll(rel, string(filepath.Separator), "-")
+		if encoded == "." || encoded == "" {
+			return filepath.Join(sessionsDir, "-")
+		}
+		return filepath.Join(sessionsDir, "-"+encoded)
+
+	case cwd == tmpdir || strings.HasPrefix(cwd, tmpdir+string(filepath.Separator)):
+		rel, _ := filepath.Rel(tmpdir, cwd)
+		encoded := strings.ReplaceAll(rel, string(filepath.Separator), "-")
+		if encoded == "." || encoded == "" {
+			return filepath.Join(sessionsDir, "-tmp")
+		}
+		return filepath.Join(sessionsDir, "-tmp-"+encoded)
+
+	default:
+		// Legacy absolute encoding — also used for dirs that haven't been migrated.
+		path := strings.TrimPrefix(cwd, "/")
+		encoded := strings.ReplaceAll(path, "/", "-")
+		return filepath.Join(sessionsDir, "--"+encoded+"--")
+	}
+}

internal/adapter/piagent/adapter.go

@@ -61,6 +61,10 @@ type toolUseRef struct {
 // Adapter implements the adapter.Adapter interface for standalone Pi Agent sessions.
 type Adapter struct {
 	sessionsDir  string
+	id           string
+	name         string
+	icon         string
+	projectDirFn func(sessionsDir, projectRoot string) string // nil → default piagent encoding
 	sessionIndex map[string]string // sessionID -> file path
 	metaCache    map[string]sessionMetaCacheEntry
 	msgCache     *cache.Cache[messageCacheEntry]
@@ -71,22 +75,38 @@ type Adapter struct {
 // New creates a new Pi Agent adapter.
 func New() *Adapter {
 	home, _ := os.UserHomeDir()
+	return NewCustom(filepath.Join(home, ".pi", "agent", "sessions"), adapterID, adapterName, adapterIcon)
+}
+
+// NewCustom creates a Pi Agent-compatible adapter with a custom sessions directory and identity.
+// Use this for forks of Pi Agent that share the same JSONL format but store sessions elsewhere.
+func NewCustom(sessionsDir, id, name, icon string) *Adapter {
 	return &Adapter{
-		sessionsDir:  filepath.Join(home, ".pi", "agent", "sessions"),
+		sessionsDir:  sessionsDir,
+		id:           id,
+		name:         name,
+		icon:         icon,
 		sessionIndex: make(map[string]string),
 		metaCache:    make(map[string]sessionMetaCacheEntry),
 		msgCache:     cache.New[messageCacheEntry](msgCacheMaxEntries),
 	}
 }
 
+// WithProjectDirFunc overrides the function used to map a project root to its
+// sessions directory. Use this for Pi forks that encode paths differently.
+func (a *Adapter) WithProjectDirFunc(fn func(sessionsDir, projectRoot string) string) *Adapter {
+	a.projectDirFn = fn
+	return a
+}
+
 // ID returns the adapter identifier.
-func (a *Adapter) ID() string { return adapterID }
+func (a *Adapter) ID() string { return a.id }
 
 // Name returns the human-readable adapter name.
-func (a *Adapter) Name() string { return adapterName }
+func (a *Adapter) Name() string { return a.name }
 
 // Icon returns the adapter icon for badge display.
-func (a *Adapter) Icon() string { return adapterIcon }
+func (a *Adapter) Icon() string { return a.icon }
 
 // Detect checks if Pi Agent sessions exist for the given project.
 func (a *Adapter) Detect(projectRoot string) (bool, error) {
@@ -267,11 +287,20 @@ func (a *Adapter) Watch(projectRoot string) (<-chan adapter.Event, io.Closer, er
 
 // projectDirPath converts a project root path to the Pi Agent sessions directory path.
 // Pi Agent encodes paths as: /home/user/project → --home-user-project--
+// If a.projectDirFn is set, it is called instead.
 func (a *Adapter) projectDirPath(projectRoot string) string {
+	if a.projectDirFn != nil {
+		return a.projectDirFn(a.sessionsDir, projectRoot)
+	}
 	absPath, err := filepath.Abs(projectRoot)
 	if err != nil {
 		absPath = projectRoot
 	}
+	// Resolve symlinks so that paths like /tmp (→ /private/tmp on macOS) match
+	// the encoding that Pi Agent uses when it records the session cwd.
+	if resolved, err := filepath.EvalSymlinks(absPath); err == nil {
+		absPath = resolved
+	}
 	// /home/user/project → --home-user-project--
 	// Strip leading slash, replace remaining slashes with dashes, wrap in --
 	path := strings.TrimPrefix(absPath, "/")

internal/adapter/piagent/adapter_test.go

@@ -27,12 +27,14 @@ func TestProjectDirPath(t *testing.T) {
 	a := New()
 
 	tests := []struct {
-		input    string
+		input      string
 		wantSuffix string
 	}{
 		{"/home/user/project", "--home-user-project--"},
 		{"/home/user/my-app", "--home-user-my-app--"},
 		{"/", "----"},
+		// /tmp is a symlink to /private/tmp on macOS; must resolve to --private-tmp--
+		{"/tmp", "--private-tmp--"},
 	}
 
 	for _, tt := range tests {