From eb5ec54cf17bf9c3be7d40feb19ebf2a39764c4f Mon Sep 17 00:00:00 2001
From: Hugo Osvaldo Barrera <hugo@whynothugo.nl>
Date: Mon, 19 Jan 2026 18:29:23 +0100
Subject: [PATCH] Resolve links relative to notebook

When running commands like such as the following:

    zk list --notebook-dir=/path/to/notebook --linked-by inbox/note.md

The path is resolved relative to the current working directory.

If the current working directory is not the notebook directory of a
child of it, resolve the link relative to the notebook root.
---
 internal/core/fs_test.go               |  7 ++-
 internal/core/notebook.go              | 15 +++++-
 internal/core/notebook_test.go         | 68 ++++++++++++++++++++++++++
 tests/linked-by-hierarchical-path.tesh | 11 +++++
 4 files changed, 99 insertions(+), 2 deletions(-)
 create mode 100644 internal/core/notebook_test.go
 create mode 100644 tests/linked-by-hierarchical-path.tesh

diff --git a/internal/core/fs_test.go b/internal/core/fs_test.go
index bf9dda8c..34657331 100644
--- a/internal/core/fs_test.go
+++ b/internal/core/fs_test.go
@@ -3,6 +3,7 @@ package core
 import (
 	"path/filepath"
 	"slices"
+	"strings"
 )
 
 // fileStorageMock implements an in-memory FileStorage for testing purposes.
@@ -61,7 +62,11 @@ func (fs *fileStorageMock) DirExists(path string) (bool, error) {
 }
 
 func (fs *fileStorageMock) IsDescendantOf(dir string, path string) (bool, error) {
-	panic("not implemented")
+	rel, err := filepath.Rel(dir, path)
+	if err != nil {
+		return false, err
+	}
+	return !filepath.IsAbs(rel) && !strings.HasPrefix(rel, ".."), nil
 }
 
 func (fs *fileStorageMock) Read(path string) ([]byte, error) {
diff --git a/internal/core/notebook.go b/internal/core/notebook.go
index 04e95524..bb29f458 100644
--- a/internal/core/notebook.go
+++ b/internal/core/notebook.go
@@ -245,7 +245,20 @@ func (n *Notebook) FindCollections(kind CollectionKind, sorters []CollectionSort
 
 // RelPath returns the path relative to the notebook root to the given path.
 func (n *Notebook) RelPath(originalPath string) (string, error) {
-	path, err := n.fs.Abs(originalPath)
+	path := originalPath
+	if !filepath.IsAbs(path) {
+		isInsideNotebook, err := n.fs.IsDescendantOf(n.Path, n.fs.WorkingDir())
+		if err != nil {
+			return path, fmt.Errorf("%v: not a valid notebook path: %w", originalPath, err)
+		}
+		if isInsideNotebook {
+			path = filepath.Join(n.fs.WorkingDir(), path)
+		} else {
+			path = filepath.Join(n.Path, path)
+		}
+	}
+
+	path, err := n.fs.Abs(path)
 	if err != nil {
 		return path, fmt.Errorf("%v: not a valid notebook path: %w", originalPath, err)
 	}
diff --git a/internal/core/notebook_test.go b/internal/core/notebook_test.go
new file mode 100644
index 00000000..668ce7ed
--- /dev/null
+++ b/internal/core/notebook_test.go
@@ -0,0 +1,68 @@
+package core
+
+import (
+	"testing"
+
+	"github.com/zk-org/zk/internal/util"
+	"github.com/zk-org/zk/internal/util/test/assert"
+)
+
+// TestRelPathResolvesInsideNotebook tests that Notebook.RelPath() resolves
+// relative paths relative to the notebook directory.
+func TestRelPathResolvesInsideNotebook(t *testing.T) {
+	notebookPath := "/notebook"
+	workingDir := "/notebook"
+
+	fs := newFileStorageMock(workingDir, []string{notebookPath})
+
+	notebook := NewNotebook(notebookPath, NewDefaultConfig(), NotebookPorts{
+		FS:     fs,
+		Logger: &util.NullLogger,
+	})
+
+	relPath, err := notebook.RelPath("inbox/note.md")
+
+	assert.Nil(t, err)
+	assert.Equal(t, relPath, "inbox/note.md")
+}
+
+// TestRelPathResolvesOutsideNotebook tests that Notebook.RelPath() resolves
+// relative paths relative to the notebook directory, not the current working
+// directory.
+func TestRelPathResolvesOutsideNotebook(t *testing.T) {
+	notebookPath := "/notebook"
+	workingDir := "/other/dir"
+
+	fs := newFileStorageMock(workingDir, []string{notebookPath})
+
+	notebook := NewNotebook(notebookPath, NewDefaultConfig(), NotebookPorts{
+		FS:     fs,
+		Logger: &util.NullLogger,
+	})
+
+	relPath, err := notebook.RelPath("inbox/note.md")
+
+	assert.Nil(t, err)
+	assert.Equal(t, relPath, "inbox/note.md")
+}
+
+// TestRelPathResolvesInsideNotebookSubdir tests that Notebook.RelPath() resolves
+// relative paths relative to the current working directory when it is a child
+// of the notebook root.
+func TestRelPathResolvesInsideNotebookSubdir(t *testing.T) {
+	notebookPath := "/notebook"
+	workingDir := "/notebook/subdir"
+
+	fs := newFileStorageMock(workingDir, []string{notebookPath, workingDir})
+
+	notebook := NewNotebook(notebookPath, NewDefaultConfig(), NotebookPorts{
+		FS:     fs,
+		Logger: &util.NullLogger,
+	})
+
+	// Relative path from /notebook/subdir should resolve to /notebook/subdir/note.md
+	relPath, err := notebook.RelPath("note.md")
+
+	assert.Nil(t, err)
+	assert.Equal(t, relPath, "subdir/note.md")
+}
diff --git a/tests/linked-by-hierarchical-path.tesh b/tests/linked-by-hierarchical-path.tesh
new file mode 100644
index 00000000..8d7808c6
--- /dev/null
+++ b/tests/linked-by-hierarchical-path.tesh
@@ -0,0 +1,11 @@
+# Running from notebook directory.
+$ cd full-sample
+$ zk list -qf\{{title}} --linked-by inbox/er4k.md
+>Channel
+>Ownership in Rust
+
+# Running from outside notebook with --notebook-dir.
+$ cd ..
+$ zk list --notebook-dir=full-sample -qf\{{title}} --linked-by inbox/er4k.md
+>Channel
+>Ownership in Rust