Fix glob expansion that includes broken symlinks

Glob expansion should use os.Lstat rather than os.Stat so that broken
symlinks don't stop glob expansion. It's not the place of glob expansion
to decide if a particular path is good.

The symlink test cases and logic were borrowed from
pkg/mods/path/path_test.go.

Fixes #1240

0.19.0-release-notes.md

@@ -24,6 +24,9 @@ and compiled, even if it is not executed:
 -   Temporary assignment on an unset environment variables no longer leave it
     set to an empty string ([#1448](https://b.elv.sh/1448)).
 
+-   Glob expansion that includes broken symlinks no longer short-circuits the
+    expansion ([#1240](https://b.elv.sh/1240)).
+
 # Notable new features
 
 -   A new `inexact-num` converts its argument to an inexact number.

pkg/glob/glob.go

@@ -72,19 +72,19 @@ func glob(segs []Segment, dir string, cb func(PathInfo) bool) bool {
 		elem := segs[0].(Literal).Data
 		segs = segs[2:]
 		dir += elem + "/"
-		if info, err := os.Stat(dir); err != nil || !info.IsDir() {
+		if info, err := os.Lstat(dir); err != nil || !info.IsDir() {
 			return true
 		}
 	}
 
 	if len(segs) == 0 {
-		if info, err := os.Stat(dir); err == nil {
+		if info, err := os.Lstat(dir); err == nil {
 			return cb(PathInfo{dir, info})
 		}
 		return true
 	} else if len(segs) == 1 && IsLiteral(segs[0]) {
 		path := dir + segs[0].(Literal).Data
-		if info, err := os.Stat(path); err == nil {
+		if info, err := os.Lstat(path); err == nil {
 			return cb(PathInfo{path, info})
 		}
 		return true
@@ -161,7 +161,7 @@ func glob(segs []Segment, dir string, cb func(PathInfo) bool) bool {
 		name := info.Name()
 		if matchElement(segs, name) {
 			dirname := dir + name
-			info, err := os.Stat(dirname)
+			info, err := os.Lstat(dirname)
 			if err != nil {
 				return true
 			}

pkg/glob/glob_test.go

@@ -20,6 +20,15 @@ var (
 		"lorem", "ipsum",
 		"d1/e/f/g/X", "d2/e/f/g/X"}
 	createDots = []string{".x", ".el/x"}
+	symlinks   = []struct {
+		path   string
+		target string
+	}{
+		{"d1/s-f", "f"},
+		{"s-d", "d2"},
+		{"s-d-f", "d1/f"},
+		{"s-bad", "bad"},
+	}
 )
 
 type globCase struct {
@@ -28,22 +37,21 @@ type globCase struct {
 }
 
 var globCases = []globCase{
-	{"*", []string{"a", "b", "c", "d1", "d2", "dX", "dXY", "lorem", "ipsum"}},
+	{"*", []string{"a", "b", "c", "d1", "d2", "dX", "dXY", "lorem", "ipsum", "s-bad", "s-d", "s-d-f"}},
 	{".", []string{"."}},
-	{"./*", []string{"./a", "./b", "./c", "./d1", "./d2", "./dX", "./dXY", "./lorem", "./ipsum"}},
+	{"./*", []string{"./a", "./b", "./c", "./d1", "./d2", "./dX", "./dXY", "./lorem", "./ipsum", "./s-bad", "./s-d", "./s-d-f"}},
 	{"..", []string{".."}},
 	{"a/..", []string{"a/.."}},
-	{"a/../*", []string{"a/../a", "a/../b", "a/../c", "a/../d1", "a/../d2", "a/../dX", "a/../dXY", "a/../lorem", "a/../ipsum"}},
+	{"a/../*", []string{"a/../a", "a/../b", "a/../c", "a/../d1", "a/../d2", "a/../dX", "a/../dXY", "a/../ipsum", "a/../lorem", "a/../s-bad", "a/../s-d", "a/../s-d-f"}},
 	{"*/", []string{"a/", "b/", "c/", "d1/", "d2/"}},
-	{"**", append(mkdirs, creates...)},
+	{"**", []string{"a", "a/X", "a/Y", "b", "b/X", "c", "c/Y", "d1", "d1/e", "d1/e/f", "d1/e/f/g", "d1/e/f/g/X", "d1/s-f", "d2", "d2/e", "d2/e/f", "d2/e/f/g", "d2/e/f/g/X", "dX", "dXY", "ipsum", "lorem", "s-bad", "s-d", "s-d-f"}},
 	{"*/X", []string{"a/X", "b/X"}},
 	{"**X", []string{"a/X", "b/X", "dX", "d1/e/f/g/X", "d2/e/f/g/X"}},
 	{"*/*/*", []string{"d1/e/f", "d2/e/f"}},
 	{"l*m", []string{"lorem"}},
 	{"d*", []string{"d1", "d2", "dX", "dXY"}},
 	{"d*/", []string{"d1/", "d2/"}},
-	{"d**", []string{"d1", "d1/e", "d1/e/f", "d1/e/f/g", "d1/e/f/g/X",
-		"d2", "d2/e", "d2/e/f", "d2/e/f/g", "d2/e/f/g/X", "dX", "dXY"}},
+	{"d**", []string{"d1", "d1/e", "d1/e/f", "d1/e/f/g", "d1/e/f/g/X", "d1/s-f", "d2", "d2/e", "d2/e/f", "d2/e/f/g", "d2/e/f/g/X", "dX", "dXY"}},
 	{"?", []string{"a", "b", "c"}},
 	{"??", []string{"d1", "d2", "dX"}},
 
@@ -80,6 +88,15 @@ func testGlob(t *testing.T, abs bool) {
 		}
 		f.Close()
 	}
+	for _, link := range symlinks {
+		err := os.Symlink(link.target, link.path)
+		if err != nil {
+			// Creating symlinks requires a special permission on Windows. If
+			// the user doesn't have that permission, just skip the whole test.
+			t.Skip(err)
+		}
+	}
+
 	for _, tc := range globCases {
 		pattern := tc.pattern
 		if abs {