Select the first bad commit once a bisect is done

When the user marks the last commit to test, the commits view keeps it
selected, and the user has to look for the result. The same happens
when lazygit starts after a bisect has finished.

After a mark, git checks out the next commit to test, unless there's
nothing left to test. In that case, the commit that the user marked
last is still the current commit, and the commit marked bad is the
first bad commit. So once the current commit is marked, select the
commit marked bad instead. Do the same if git never checked out a
commit to test, because the good commit is a parent of the bad one.

If only skipped commits are left to test, the first bad commit is
either one of them or the commit marked bad. Select the commit marked
bad then too; it's the newest of the candidates.

The commits view loads the commits down to the commit that it selects,
so this one is always loaded.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

pkg/commands/git_commands/bisect_info.go

@@ -63,6 +63,21 @@ func (self *BisectInfo) GetCurrentHash() string {
 	return self.current
 }
 
+// Whether git has checked out a commit for the user to test, and the user
+// hasn't marked it yet. After the user marks it, git checks out the next one,
+// unless there's nothing left to test. This is the case if git has found the
+// first new commit, or if only skipped commits are left. Git checks out the
+// first commit to test once it knows both a new and an old commit, unless the
+// old commit is a parent of the new one.
+func (self *BisectInfo) HasCommitToTest() bool {
+	if self.current == "" {
+		return false
+	}
+
+	_, marked := self.statusMap[self.current]
+	return !marked
+}
+
 func (self *BisectInfo) GetStartHash() string {
 	return self.start
 }

pkg/gui/controllers/helpers/refresh_helper.go

@@ -1036,13 +1036,20 @@ func findNewBisectCommitToSelect(previousBisectInfo *git_commands.BisectInfo, bi
 }
 
 // Returns the commit that the user needs to look at during a bisect: the one
-// that git wants them to test. Returns "" if there's none.
+// that git wants them to test, or the first bad commit once git has found it.
+// Returns "" if git doesn't know both a good and a bad commit yet.
 func bisectCommitToSelect(bisectInfo *git_commands.BisectInfo) string {
 	if !bisectInfo.Bisecting() {
 		return ""
 	}
 
-	return bisectInfo.GetCurrentHash()
+	if bisectInfo.HasCommitToTest() {
+		return bisectInfo.GetCurrentHash()
+	}
+
+	// There's nothing left to test, so the commit marked bad is the first bad
+	// commit. (If only skipped commits are left, it is one of the candidates.)
+	return bisectInfo.GetNewHash()
 }
 
 // capturedSubCommitState holds the sub-commits refresh's model/context/mode

pkg/integration/tests/bisect/select_first_bad_commit.go

@@ -34,9 +34,6 @@ var SelectFirstBadCommit = NewIntegrationTest(NewIntegrationTestArgs{
 
 				t.ExpectPopup().Alert().Title(Equals("Bisect complete")).Content(MatchesRegexp("(?s)commit-08.*Do you want to reset")).Cancel()
 			}).
-			/* EXPECTED:
 			SelectedLine(Contains("CI commit-08").Contains("<-- bad"))
-			ACTUAL: */
-			SelectedLine(Contains("CI commit-07"))
 	},
 })

pkg/integration/tests/bisect/select_first_bad_commit_on_startup.go

@@ -23,9 +23,6 @@ var SelectFirstBadCommitOnStartup = NewIntegrationTest(NewIntegrationTestArgs{
 	Run: func(t *TestDriver, keys config.KeybindingConfig) {
 		t.Views().Commits().
 			IsFocused().
-			/* EXPECTED:
 			SelectedLine(Contains("CI commit-08").Contains("<-- bad"))
-			ACTUAL: */
-			SelectedLine(Contains("CI commit-07"))
 	},
 })