caddyconfig: Don't start comments in middle of tokens (#3267)

* caddyconfig: Only parse # as start of comment if preceded by space

* caddyconfig: Simplify # logic using len(val), add a test

caddyconfig/caddyfile/formatter.go

@@ -131,9 +131,6 @@ func Format(input []byte) []byte {
 		//////////////////////////////////////////////////////////
 
 		if ch == '#' {
-			if !spacePrior && !beginningOfLine {
-				write(' ')
-			}
 			comment = true
 		}
 

caddyconfig/caddyfile/formatter_test.go

@@ -305,6 +305,11 @@ bar "{\"key\":34}"`,
 
 baz`,
 		},
+		{
+			description: "hash within string is not a comment",
+			input:       `redir / /some/#/path`,
+			expect:      `redir / /some/#/path`,
+		},
 	} {
 		// the formatter should output a trailing newline,
 		// even if the tests aren't written to expect that

caddyconfig/caddyfile/lexer.go

@@ -141,7 +141,7 @@ func (l *lexer) next() bool {
 			continue
 		}
 
-		if ch == '#' {
+		if ch == '#' && len(val) == 0 {
 			comment = true
 		}
 		if comment {

caddyconfig/caddyfile/lexer_test.go

@@ -77,6 +77,26 @@ func TestLexer(t *testing.T) {
 				{Line: 6, Text: "}"},
 			},
 		},
+		{
+			input: `host:123 {
+						# hash inside string is not a comment
+						redir / /some/#/path
+					}`,
+			expected: []Token{
+				{Line: 1, Text: "host:123"},
+				{Line: 1, Text: "{"},
+				{Line: 3, Text: "redir"},
+				{Line: 3, Text: "/"},
+				{Line: 3, Text: "/some/#/path"},
+				{Line: 4, Text: "}"},
+			},
+		},
+		{
+			input: "# comment at beginning of file\n# comment at beginning of line\nhost:123",
+			expected: []Token{
+				{Line: 3, Text: "host:123"},
+			},
+		},
 		{
 			input: `a "quoted value" b
 					foobar`,