httpcaddyfile: keep source order for vars with non-comparable matchers (#8197)

Use i/j swap instead of !sortByPath for vars, so matchers that can't
be compared keep their Caddyfile order. Path matchers still sort with
the more specific one later. Fixes the vars ordering part of #8187.

caddyconfig/httpcaddyfile/directives.go

@@ -465,6 +465,15 @@ func sortRoutes(routes []ConfigValue, order []string) {
 			return dirPositions[iDir] < dirPositions[jDir]
 		}
 
+		// some directives involve setting values which can overwrite
+		// each other, so it makes most sense to reverse the order so
+		// that the least-specific matcher is first, allowing the last
+		// matching one to win; we swap i and j instead of using !,
+		// so matchers that can't be compared keep their order
+		if iDir == "vars" {
+			i, j = j, i
+		}
+
 		// directives are the same; sub-sort by path matcher length if there's
 		// only one matcher set and one path (this is a very common case and
 		// usually -- but not always -- helpful/expected, oh well; user can
@@ -535,15 +544,7 @@ func sortRoutes(routes []ConfigValue, order []string) {
 			return len(iRoute.MatcherSetsRaw) > 0 && len(jRoute.MatcherSetsRaw) == 0
 		}()
 
-		// some directives involve setting values which can overwrite
-		// each other, so it makes most sense to reverse the order so
-		// that the least-specific matcher is first, allowing the last
-		// matching one to win
-		if iDir == "vars" {
-			return !sortByPath
-		}
-
-		// everything else is most-specific matcher first
+		// most-specific matcher first (or last for vars, see above)
 		return sortByPath
 	})
 }

caddytest/integration/caddyfile_adapt/map_and_vars_with_raw_types.caddyfiletest

@@ -101,16 +101,16 @@ vars {
 													],
 													"source": "{http.request.host}"
 												},
+												{
+													"foo": "bar",
+													"handler": "vars"
+												},
 												{
 													"abc": true,
 													"def": 1,
 													"ghi": 2.3,
 													"handler": "vars",
 													"jkl": "mn op"
-												},
-												{
-													"foo": "bar",
-													"handler": "vars"
 												}
 											]
 										}

caddytest/integration/caddyfile_adapt/sort_vars_named_matchers_keep_order.caddyfiletest

@@ -0,0 +1,63 @@
+:80
+
+@first header X-Test a
+@second header X-Test a
+@third header X-Other b
+
+vars @first value first
+vars @second value second
+vars @third value third
+----------
+{
+	"apps": {
+		"http": {
+			"servers": {
+				"srv0": {
+					"listen": [
+						":80"
+					],
+					"routes": [
+						{
+							"match": [
+								{
+									"header": {
+										"X-Test": [
+											"a"
+										]
+									}
+								}
+							],
+							"handle": [
+								{
+									"handler": "vars",
+									"value": "first"
+								},
+								{
+									"handler": "vars",
+									"value": "second"
+								}
+							]
+						},
+						{
+							"match": [
+								{
+									"header": {
+										"X-Other": [
+											"b"
+										]
+									}
+								}
+							],
+							"handle": [
+								{
+									"handler": "vars",
+									"value": "third"
+								}
+							]
+						}
+					]
+				}
+			}
+		}
+	}
+}