fix: resolve Python dot-notation imports in dependency graph (#8)

Python relative imports (.models, ..utils) and dotted absolute imports
(myapp.db.client) were silently dropped because resolveImport only
handled path-style separators (./foo, ../foo). Adds normalizePythonImport
to convert dot-prefix to path-style, and slash-converts dotted package
imports for module matching.

Fixes #7

Author: thegdsks

internal/graph/graph.go

@@ -284,6 +284,12 @@ func detectModuleWithDepth(filePath string, maxDepth int) string {
 // resolveImport attempts to match an import string to a known module name.
 // Returns the matched module name, or "" if no match (external dependency).
 func resolveImport(imp, fileDir string, knownModules []string) string {
+	// Normalize Python dot-notation imports to path-style.
+	// ".models" → "./models", "..utils" → "../utils", "...core" → "../../core"
+	if normalized, ok := normalizePythonImport(imp); ok {
+		imp = normalized
+	}
+
 	// Relative imports: ./foo or ../foo
 	if strings.HasPrefix(imp, "./") || strings.HasPrefix(imp, "../") {
 		resolved := filepath.Clean(filepath.Join(fileDir, imp))
@@ -304,23 +310,56 @@ func resolveImport(imp, fileDir string, knownModules []string) string {
 
 	// Absolute/package-style imports: match suffix against known module names.
 	// e.g. import "internal/auth" matches module "internal/auth".
+	// Also convert dotted imports (Python "os.path" → "os/path") for matching.
+	slashImp := strings.ReplaceAll(imp, ".", "/")
+
 	for _, mod := range knownModules {
-		if mod == imp {
+		if mod == imp || mod == slashImp {
 			return mod
 		}
 		// Suffix match: "internal/auth" matches module "internal/auth".
-		if strings.HasSuffix(imp, "/"+mod) || strings.HasSuffix(imp, mod) {
+		if strings.HasSuffix(imp, "/"+mod) || strings.HasSuffix(slashImp, "/"+mod) {
+			return mod
+		}
+		// Module is a prefix of the import path (package.submodule → package/).
+		if strings.HasPrefix(slashImp, mod+"/") || strings.HasPrefix(imp, mod+"/") {
 			return mod
 		}
 		// Module is a suffix of the import path (Go-style).
-		if strings.HasSuffix(imp, mod) || imp == mod {
+		if strings.HasSuffix(imp, mod) || strings.HasSuffix(slashImp, mod) {
 			return mod
 		}
 	}
 
 	return ""
 }
 
+// normalizePythonImport converts Python dot-prefix relative imports to path-style.
+// ".models" → ("./models", true), "..utils" → ("../utils", true), "os" → ("", false).
+func normalizePythonImport(imp string) (string, bool) {
+	if !strings.HasPrefix(imp, ".") {
+		return "", false
+	}
+	// Count leading dots.
+	dots := 0
+	for dots < len(imp) && imp[dots] == '.' {
+		dots++
+	}
+	rest := imp[dots:]
+	if rest == "" {
+		// Bare relative like "." or ".." without module name — can't resolve.
+		return "", false
+	}
+	// Convert dots to path: 1 dot → "./", 2 dots → "../", 3 dots → "../../", etc.
+	prefix := "./"
+	for i := 1; i < dots; i++ {
+		prefix = "../" + prefix
+	}
+	// Replace remaining dots in module name with slashes (e.g. ".foo.bar" → "./foo/bar").
+	rest = strings.ReplaceAll(rest, ".", "/")
+	return prefix + rest, true
+}
+
 // appendUnique appends values to s, skipping duplicates.
 func appendUnique(s []string, values ...string) []string {
 	set := make(map[string]struct{}, len(s))

internal/graph/graph_test.go

@@ -144,6 +144,64 @@ func TestIsolatedModules(t *testing.T) {
 	}
 }
 
+// TestPythonRelativeImports verifies that Python dot-notation relative imports
+// produce correct dependency edges.
+func TestPythonRelativeImports(t *testing.T) {
+	files := []*parser.FileInfo{
+		{Path: "myapp/api/views.py", Language: "python", Imports: []string{"flask", ".models", ".config"}, LineCount: 30},
+		{Path: "myapp/api/models.py", Language: "python", Exports: []string{"User", "Post"}, LineCount: 20},
+		{Path: "myapp/api/config.py", Language: "python", Exports: []string{"Settings"}, LineCount: 10},
+		{Path: "myapp/db/client.py", Language: "python", Exports: []string{"get_conn"}, LineCount: 15},
+	}
+
+	g := Build(files, BuildOptions{MaxDepth: 4})
+
+	apiMod := g.Module("myapp/api")
+	if apiMod == nil {
+		t.Fatal("expected module myapp/api to exist")
+	}
+
+	// ".models" and ".config" are in the same directory so they resolve to same module.
+	// They should NOT create self-edges. External "flask" should not appear.
+	if len(apiMod.DependsOn) != 0 {
+		t.Errorf("expected no external deps (self-refs filtered), got %v", apiMod.DependsOn)
+	}
+}
+
+// TestPythonParentRelativeImport verifies that ".." style Python imports resolve
+// to the parent module.
+func TestPythonParentRelativeImport(t *testing.T) {
+	files := []*parser.FileInfo{
+		{Path: "myapp/api/views.py", Language: "python", Imports: []string{"..db"}, LineCount: 30},
+		{Path: "myapp/db/client.py", Language: "python", Exports: []string{"get_conn"}, LineCount: 15},
+	}
+
+	g := Build(files, BuildOptions{MaxDepth: 4})
+
+	apiMod := g.Module("myapp/api")
+	if apiMod == nil {
+		t.Fatal("expected module myapp/api to exist")
+	}
+	assertStringSliceContains(t, apiMod.DependsOn, "myapp/db")
+}
+
+// TestPythonDottedAbsoluteImport verifies that Python dotted absolute imports
+// (e.g. "myapp.db.client") resolve to the correct module.
+func TestPythonDottedAbsoluteImport(t *testing.T) {
+	files := []*parser.FileInfo{
+		{Path: "myapp/api/views.py", Language: "python", Imports: []string{"myapp.db.client"}, LineCount: 30},
+		{Path: "myapp/db/client.py", Language: "python", Exports: []string{"get_conn"}, LineCount: 15},
+	}
+
+	g := Build(files, BuildOptions{MaxDepth: 4})
+
+	apiMod := g.Module("myapp/api")
+	if apiMod == nil {
+		t.Fatal("expected module myapp/api to exist")
+	}
+	assertStringSliceContains(t, apiMod.DependsOn, "myapp/db")
+}
+
 // moduleNames is a helper to extract names for error messages.
 func moduleNames(mods []*Module) []string {
 	names := make([]string, len(mods))

stacklit.json

@@ -1,7 +1,7 @@
 {
   "$schema": "https://stacklit.dev/schema/v1.json",
   "version": "1",
-  "generated_at": "2026-04-10T19:17:44Z",
+  "generated_at": "2026-04-10T19:43:30Z",
   "stacklit_version": "dev",
   "merkle_hash": "30be93d7f694cca2cd354dcaaa49aa84329732f577399f2f0fddaffcfab3b5ef",
   "project": {
@@ -418,9 +418,9 @@
         "type Project"
       ],
       "type_defs": {
-        "Architecture": "Pattern string, Summary string",
+        "Dependencies": "Edges [][]string, Entrypoints []string, MostDepended []string, Isolated []string",
+        "GitInfo": "HotFiles []HotFile, Recent []string, Stable []string",
         "Hints": "AddFeature string, TestCmd string, EnvVars []string, DoNotTouch []string",
-        "HotFile": "Path string, Commits90d int",
         "Index": "Schema string, Version string, GeneratedAt string, StacklitVersion string, MerkleHash string, Project Project, Tech Tech, Structure Structure, Modules map[string]ModuleInfo, Dependencies Dependenci...",
         "LangStats": "Files int, Lines int",
         "ModuleInfo": "Purpose string, Language string, Files int, Lines int, FileList []string, Exports []string, TypeDefs map[string]string, DependsOn []string, DependedBy []string, Activity string",
@@ -660,19 +660,19 @@
     "hot_files": [
       {
         "path": "stacklit.json",
-        "commits_90d": 17
+        "commits_90d": 18
       },
       {
         "path": "stacklit.mmd",
         "commits_90d": 14
       },
       {
-        "path": "internal/engine/engine.go",
+        "path": "README.md",
         "commits_90d": 13
       },
       {
-        "path": "README.md",
-        "commits_90d": 12
+        "path": "internal/engine/engine.go",
+        "commits_90d": 13
       },
       {
         "path": "assets/template.html",
@@ -740,11 +740,11 @@
       }
     ],
     "recent": [
-      "npm/install.js",
+      "README.md",
       "stacklit.json",
+      "npm/install.js",
       ".gitignore",
       "COMPARISON.md",
-      "README.md",
       "USAGE.md",
       "examples/README.md",
       "internal/cli/derive.go",