fix a bug that go parser fails to extract a package-level variable usage (#67)

Author: angrychow

go.mod

@@ -14,6 +14,7 @@ require (
 	github.com/fsnotify/fsnotify v1.4.9
 	github.com/invopop/jsonschema v0.13.0
 	github.com/mark3labs/mcp-go v0.34.0
+	github.com/pkg/errors v0.9.1
 	github.com/sourcegraph/go-lsp v0.0.0-20240223163137-f80c5dd31dfd
 	github.com/sourcegraph/jsonrpc2 v0.2.0
 	github.com/stretchr/testify v1.10.0
@@ -67,7 +68,6 @@ require (
 	github.com/openai/openai-go v1.10.1 // indirect
 	github.com/pelletier/go-toml/v2 v2.2.3 // indirect
 	github.com/perimeterx/marshmallow v1.1.5 // indirect
-	github.com/pkg/errors v0.9.1 // indirect
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
 	github.com/sirupsen/logrus v1.9.3 // indirect
 	github.com/slongfield/pyfmt v0.0.0-20220222012616-ea85ff4c361f // indirect

lang/golang/parser/file.go

@@ -295,6 +295,26 @@ func (p *GoParser) parseSelector(ctx *fileContext, expr *ast.SelectorExpr, infos
 					return false
 				}
 				return false
+			} else if obj, ok := use.(*types.Var); ok {
+				// collect global var
+				addPkgVarDep := func() {
+					pkg := obj.Pkg()
+					if pkg == nil {
+						return
+					}
+					path := pkg.Path()
+					mod, err := ctx.GetMod(path)
+					if err != nil {
+						return
+					}
+					id := NewIdentity(mod, path, obj.Name())
+					dep := NewDependency(id, ctx.FileLine(ident))
+					infos.globalVars = InsertDependency(infos.globalVars, dep)
+				}
+				// check if it is a global var
+				if isPkgScope(obj.Parent()) {
+					addPkgVarDep()
+				}
 			}
 		}
 	} else if sel, ok := expr.X.(*ast.SelectorExpr); ok {