Use beforeCommit instead of baseCommit (#22949)

Replaces: #22947
Fixes #22946
Probably related to #19530

Basically, many of the diffs were broken because they were comparing to
the base commit, where a 3-dot diff should be comparing to the [last
common
ancestor](https://matthew-brett.github.io/pydagogue/git_diff_dots.html).

This should have an integration test so that we don’t run into this
issue again.

---------

Co-authored-by: Jonathan Tran <[email protected]>

Author: kdumontnu

models/db/iterate_test.go

@@ -25,7 +25,7 @@ func TestIterate(t *testing.T) {
 		return nil
 	})
 	assert.NoError(t, err)
-	assert.EqualValues(t, 81, repoCnt)
+	assert.EqualValues(t, 83, repoCnt)
 
 	err = db.Iterate(db.DefaultContext, nil, func(ctx context.Context, repoUnit *repo_model.RepoUnit) error {
 		reopUnit2 := repo_model.RepoUnit{ID: repoUnit.ID}

models/fixtures/repo_unit.yml

@@ -556,3 +556,16 @@
   repo_id: 54
   type: 1
   created_unix: 946684810
+
+-
+  id: 82
+  repo_id: 31
+  type: 1
+  created_unix: 946684810
+
+-
+  id: 83
+  repo_id: 31
+  type: 3
+  config: "{\"IgnoreWhitespaceConflicts\":false,\"AllowMerge\":true,\"AllowRebase\":true,\"AllowRebaseMerge\":true,\"AllowSquash\":true}"
+  created_unix: 946684810

routers/web/repo/compare.go

@@ -43,8 +43,8 @@ const (
 )
 
 // setCompareContext sets context data.
-func setCompareContext(ctx *context.Context, base, head *git.Commit, headOwner, headName string) {
-	ctx.Data["BaseCommit"] = base
+func setCompareContext(ctx *context.Context, before, head *git.Commit, headOwner, headName string) {
+	ctx.Data["BeforeCommit"] = before
 	ctx.Data["HeadCommit"] = head
 
 	ctx.Data["GetBlobByPathForCommit"] = func(commit *git.Commit, path string) *git.Blob {
@@ -59,7 +59,7 @@ func setCompareContext(ctx *context.Context, base, head *git.Commit, headOwner,
 		return blob
 	}
 
-	setPathsCompareContext(ctx, base, head, headOwner, headName)
+	setPathsCompareContext(ctx, before, head, headOwner, headName)
 	setImageCompareContext(ctx)
 	setCsvCompareContext(ctx)
 }
@@ -629,9 +629,8 @@ func PrepareCompareDiff(
 	}
 
 	baseGitRepo := ctx.Repo.GitRepo
-	baseCommitID := ci.CompareInfo.BaseCommitID
 
-	baseCommit, err := baseGitRepo.GetCommit(baseCommitID)
+	beforeCommit, err := baseGitRepo.GetCommit(beforeCommitID)
 	if err != nil {
 		ctx.ServerError("GetCommit", err)
 		return false
@@ -668,7 +667,7 @@ func PrepareCompareDiff(
 	ctx.Data["Username"] = ci.HeadUser.Name
 	ctx.Data["Reponame"] = ci.HeadRepo.Name
 
-	setCompareContext(ctx, baseCommit, headCommit, ci.HeadUser.Name, repo.Name)
+	setCompareContext(ctx, beforeCommit, headCommit, ci.HeadUser.Name, repo.Name)
 
 	return false
 }

templates/repo/diff/box.tmpl

@@ -71,7 +71,7 @@
 				<div id="diff-file-boxes" class="sixteen wide column">
 					{{range $i, $file := .Diff.Files}}
 						{{/*notice: the index of Diff.Files should not be used for element ID, because the index will be restarted from 0 when doing load-more for PRs with a lot of files*/}}
-						{{$blobBase := call $.GetBlobByPathForCommit $.BaseCommit $file.OldName}}
+						{{$blobBase := call $.GetBlobByPathForCommit $.BeforeCommit $file.OldName}}
 						{{$blobHead := call $.GetBlobByPathForCommit $.HeadCommit $file.Name}}
 						{{$isImage := or (call $.IsBlobAnImage $blobBase) (call $.IsBlobAnImage $blobHead)}}
 						{{$isCsv := (call $.IsCsvFile $file)}}

tests/gitea-repositories-meta/user2/repo20.git/hooks/post-receive.d/gitea

@@ -1,2 +1,2 @@
 #!/usr/bin/env bash
-"/home/tris/Projects/go/src/code.gitea.io/gitea/gitea" hook --config='/home/tris/Projects/go/src/code.gitea.io/gitea/custom/conf/app.ini' post-receive
+"$GITEA_ROOT/gitea" hook --config="$GITEA_ROOT/$GITEA_CONF" post-receive

tests/gitea-repositories-meta/user2/repo20.git/hooks/pre-receive.d/gitea

@@ -1,2 +1,2 @@
 #!/usr/bin/env bash
-"/home/tris/Projects/go/src/code.gitea.io/gitea/gitea" hook --config='/home/tris/Projects/go/src/code.gitea.io/gitea/custom/conf/app.ini' pre-receive
+"$GITEA_ROOT/gitea" hook --config="$GITEA_ROOT/$GITEA_CONF" pre-receive

tests/gitea-repositories-meta/user2/repo20.git/hooks/update.d/gitea

@@ -1,2 +1,2 @@
 #!/usr/bin/env bash
-"/home/tris/Projects/go/src/code.gitea.io/gitea/gitea" hook --config='/home/tris/Projects/go/src/code.gitea.io/gitea/custom/conf/app.ini' update $1 $2 $3
+"$GITEA_ROOT/gitea" hook --config="$GITEA_ROOT/$GITEA_CONF" update $1 $2 $3

tests/gitea-repositories-meta/user2/repo20.git/objects/07/0b2e783a6b3e521a23fdead377a3e41a04410d

@@ -0,0 +1 @@
+x
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