improve the compare page (#36261)

- The compare page head title should be `compare` but not `new pull
request`.
- Use `UnstableGuessRefByShortName` instead of duplicated functions
calls.
- Direct-compare, tags, commits compare will not display `New Pull
Request` button any more.

The new screenshot
<img width="1459" height="391" alt="image"
src="https://github.com/user-attachments/assets/64e9b070-9c0b-41d1-b4b8-233b96270e1b"
/>

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

routers/common/compare_test.go

@@ -6,146 +6,100 @@ package common
 import (
 	"testing"
 
-	"code.gitea.io/gitea/models/unittest"
-
 	"github.com/stretchr/testify/assert"
 )
 
 func TestCompareRouterReq(t *testing.T) {
-	unittest.PrepareTestEnv(t)
-
-	kases := []struct {
-		router           string
+	cases := []struct {
+		input            string
 		CompareRouterReq *CompareRouterReq
 	}{
 		{
-			router: "",
+			input:            "",
+			CompareRouterReq: &CompareRouterReq{},
+		},
+		{
+			input: "v1.0...v1.1",
 			CompareRouterReq: &CompareRouterReq{
-				BaseOriRef: "",
-				HeadOriRef: "",
-				DotTimes:   0,
+				BaseOriRef:       "v1.0",
+				CompareSeparator: "...",
+				HeadOriRef:       "v1.1",
 			},
 		},
 		{
-			router: "main...develop",
+			input: "main..develop",
 			CompareRouterReq: &CompareRouterReq{
-				BaseOriRef: "main",
-				HeadOriRef: "develop",
-				DotTimes:   3,
+				BaseOriRef:       "main",
+				CompareSeparator: "..",
+				HeadOriRef:       "develop",
 			},
 		},
 		{
-			router: "main..develop",
+			input: "main^...develop",
 			CompareRouterReq: &CompareRouterReq{
-				BaseOriRef: "main",
-				HeadOriRef: "develop",
-				DotTimes:   2,
+				BaseOriRef:       "main",
+				BaseOriRefSuffix: "^",
+				CompareSeparator: "...",
+				HeadOriRef:       "develop",
 			},
 		},
 		{
-			router: "main^...develop",
+			input: "main^^^^^...develop",
 			CompareRouterReq: &CompareRouterReq{
-				BaseOriRef: "main",
-				HeadOriRef: "develop",
-				CaretTimes: 1,
-				DotTimes:   3,
+				BaseOriRef:       "main",
+				BaseOriRefSuffix: "^^^^^",
+				CompareSeparator: "...",
+				HeadOriRef:       "develop",
 			},
 		},
 		{
-			router: "main^^^^^...develop",
+			input: "develop",
 			CompareRouterReq: &CompareRouterReq{
-				BaseOriRef: "main",
-				HeadOriRef: "develop",
-				CaretTimes: 5,
-				DotTimes:   3,
+				CompareSeparator: "...",
+				HeadOriRef:       "develop",
 			},
 		},
 		{
-			router: "develop",
+			input: "teabot:feature1",
 			CompareRouterReq: &CompareRouterReq{
-				HeadOriRef: "develop",
-				DotTimes:   3,
+				CompareSeparator: "...",
+				HeadOwner:        "teabot",
+				HeadOriRef:       "feature1",
 			},
 		},
 		{
-			router: "lunny/forked_repo:develop",
+			input: "lunny/forked_repo:develop",
 			CompareRouterReq: &CompareRouterReq{
-				HeadOwner:    "lunny",
-				HeadRepoName: "forked_repo",
-				HeadOriRef:   "develop",
-				DotTimes:     3,
+				CompareSeparator: "...",
+				HeadOwner:        "lunny",
+				HeadRepoName:     "forked_repo",
+				HeadOriRef:       "develop",
 			},
 		},
 		{
-			router: "main...lunny/forked_repo:develop",
+			input: "main...lunny/forked_repo:develop",
 			CompareRouterReq: &CompareRouterReq{
-				BaseOriRef:   "main",
-				HeadOwner:    "lunny",
-				HeadRepoName: "forked_repo",
-				HeadOriRef:   "develop",
-				DotTimes:     3,
+				BaseOriRef:       "main",
+				CompareSeparator: "...",
+				HeadOwner:        "lunny",
+				HeadRepoName:     "forked_repo",
+				HeadOriRef:       "develop",
 			},
 		},
 		{
-			router: "main...lunny/forked_repo:develop",
+			input: "main^...lunny/forked_repo:develop",
 			CompareRouterReq: &CompareRouterReq{
-				BaseOriRef:   "main",
-				HeadOwner:    "lunny",
-				HeadRepoName: "forked_repo",
-				HeadOriRef:   "develop",
-				DotTimes:     3,
-			},
-		},
-		{
-			router: "main^...lunny/forked_repo:develop",
-			CompareRouterReq: &CompareRouterReq{
-				BaseOriRef:   "main",
-				HeadOwner:    "lunny",
-				HeadRepoName: "forked_repo",
-				HeadOriRef:   "develop",
-				DotTimes:     3,
-				CaretTimes:   1,
-			},
-		},
-		{
-			router: "v1.0...v1.1",
-			CompareRouterReq: &CompareRouterReq{
-				BaseOriRef: "v1.0",
-				HeadOriRef: "v1.1",
-				DotTimes:   3,
-			},
-		},
-		{
-			router: "teabot-patch-1...v0.0.1",
-			CompareRouterReq: &CompareRouterReq{
-				BaseOriRef: "teabot-patch-1",
-				HeadOriRef: "v0.0.1",
-				DotTimes:   3,
-			},
-		},
-		{
-			router: "teabot:feature1",
-			CompareRouterReq: &CompareRouterReq{
-				HeadOwner:  "teabot",
-				HeadOriRef: "feature1",
-				DotTimes:   3,
-			},
-		},
-		{
-			router: "8eb19a5ae19abae15c0666d4ab98906139a7f439...283c030497b455ecfa759d4649f9f8b45158742e",
-			CompareRouterReq: &CompareRouterReq{
-				BaseOriRef: "8eb19a5ae19abae15c0666d4ab98906139a7f439",
-				HeadOriRef: "283c030497b455ecfa759d4649f9f8b45158742e",
-				DotTimes:   3,
+				BaseOriRef:       "main",
+				BaseOriRefSuffix: "^",
+				CompareSeparator: "...",
+				HeadOwner:        "lunny",
+				HeadRepoName:     "forked_repo",
+				HeadOriRef:       "develop",
 			},
 		},
 	}
 
-	for _, kase := range kases {
-		t.Run(kase.router, func(t *testing.T) {
-			r, err := ParseCompareRouterParam(kase.router)
-			assert.NoError(t, err)
-			assert.Equal(t, kase.CompareRouterReq, r)
-		})
+	for _, c := range cases {
+		assert.Equal(t, c.CompareRouterReq, ParseCompareRouterParam(c.input), "input: %s", c.input)
 	}
 }