Print helpful message when branch already exists (#274)

mattprecious · Feb 25, 2025 · 954a829 · 954a829
1 parent f08604d
commit 954a829
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Showing 4 changed files with 55 additions and 5 deletions.
diff --git a/src/commonMain/kotlin/com/mattprecious/stacker/command/branch/BranchCreate.kt b/src/commonMain/kotlin/com/mattprecious/stacker/command/branch/BranchCreate.kt
@@ -11,6 +11,7 @@ import com.mattprecious.stacker.rendering.branch
 import com.mattprecious.stacker.rendering.code
 import com.mattprecious.stacker.stack.StackManager
 import com.mattprecious.stacker.vc.VersionControl
+import com.mattprecious.stacker.vc.VersionControl.BranchCreateResult
 
 fun StackerDeps.branchCreate(
 	branchName: String,
@@ -49,7 +50,21 @@ internal class BranchCreate(
 			abort()
 		}
 
-		vc.createBranchFromCurrent(branchName)
-		stackManager.trackBranch(branchName, currentBranch.name, vc.getSha(currentBranch.name))
+		when (vc.createBranchFromCurrent(branchName)) {
+			BranchCreateResult.Success -> {
+				stackManager.trackBranch(branchName, currentBranch.name, vc.getSha(currentBranch.name))
+			}
+			BranchCreateResult.AlreadyExists -> {
+				printStaticError(
+					buildAnnotatedString {
+						append("Branch ")
+						branch { append(branchName) }
+						append(" already exists.")
+					},
+				)
+
+				abort()
+			}
+		}
 	}
 }
diff --git a/src/commonMain/kotlin/com/mattprecious/stacker/vc/GitVersionControl.kt b/src/commonMain/kotlin/com/mattprecious/stacker/vc/GitVersionControl.kt
@@ -5,6 +5,7 @@ import com.github.git2.GIT_CHECKOUT_OPTIONS_VERSION
 import com.github.git2.GIT_CREDTYPE_SSH_KEY
 import com.github.git2.GIT_EAPPLIED
 import com.github.git2.GIT_ECONFLICT
+import com.github.git2.GIT_EEXISTS
 import com.github.git2.GIT_ENOTFOUND
 import com.github.git2.GIT_EUNMERGED
 import com.github.git2.GIT_FETCH_OPTIONS_VERSION
@@ -97,6 +98,8 @@ import com.github.git2.git_signature_default_from_env
 import com.github.git2.git_signature_free
 import com.github.git2.git_strarray
 import com.mattprecious.stacker.shell.Shell
+import com.mattprecious.stacker.vc.ReturnCodes.EEXISTS
+import com.mattprecious.stacker.vc.VersionControl.BranchCreateResult
 import com.mattprecious.stacker.vc.VersionControl.CommitInfo
 import kotlinx.cinterop.CPointer
 import kotlinx.cinterop.CPointerVar
@@ -196,10 +199,14 @@ class GitVersionControl(
 		checkout(branchName, treeish.pointed!!)
 	}
 
-	override fun createBranchFromCurrent(branchName: String) = memScoped {
+	override fun createBranchFromCurrent(branchName: String): BranchCreateResult = memScoped {
 		val commit = getCommitForBranch(currentBranchName)
-		checkError(git_branch_create(allocPointerTo<git_reference>().ptr, repo, branchName, commit.ptr, 0))
+		val code =
+			git_branch_create(allocPointerTo<git_reference>().ptr, repo, branchName, commit.ptr, 0)
+		if (code == EEXISTS) return BranchCreateResult.AlreadyExists
+		checkError(code)
 		checkout(branchName, commit.asObject())
+		return BranchCreateResult.Success
 	}
 
 	override fun renameBranch(branchName: String, newName: String) = memScoped {
@@ -590,6 +597,7 @@ private fun checkError(result: Int) {
 private object ReturnCodes {
 	val OK = GIT_OK
 	val ENOTFOUND = GIT_ENOTFOUND
+	val EEXISTS = GIT_EEXISTS
 	val EUNMERGED = GIT_EUNMERGED
 	val ECONFLICT = GIT_ECONFLICT
 	val EAPPLIED = GIT_EAPPLIED

diff --git a/src/commonMain/kotlin/com/mattprecious/stacker/vc/VersionControl.kt b/src/commonMain/kotlin/com/mattprecious/stacker/vc/VersionControl.kt
@@ -18,7 +18,12 @@ interface VersionControl : AutoCloseable {
 
 	fun checkout(branchName: String)
 
-	fun createBranchFromCurrent(branchName: String)
+	enum class BranchCreateResult {
+		Success,
+		AlreadyExists,
+	}
+
+	fun createBranchFromCurrent(branchName: String): BranchCreateResult
 
 	fun renameBranch(branchName: String, newName: String)
 

diff --git a/src/commonTest/kotlin/com/mattprecious/stacker/test/command/BranchCreateTest.kt b/src/commonTest/kotlin/com/mattprecious/stacker/test/command/BranchCreateTest.kt
@@ -11,6 +11,7 @@ import com.mattprecious.stacker.db.Branch
 import com.mattprecious.stacker.delegates.Optional
 import com.mattprecious.stacker.test.util.gitCommit
 import com.mattprecious.stacker.test.util.gitCreateAndCheckoutBranch
+import com.mattprecious.stacker.test.util.gitCreateBranch
 import com.mattprecious.stacker.test.util.gitInit
 import com.mattprecious.stacker.test.util.withTestEnvironment
 import kotlin.test.Test
@@ -108,4 +109,25 @@ class BranchCreateTest {
 				.containsExactly("main")
 		}
 	}
+
+	@Test
+	fun duplicateBranch() = withTestEnvironment {
+		gitInit()
+		gitCommit("Empty")
+		testCommand({ repoInit("main", Optional.None) })
+		gitCreateBranch("change-a")
+
+		testCommand({ branchCreate("change-a") }) {
+			awaitFrame(
+				static = "Branch change-a already exists.",
+				output = "",
+			)
+			assertThat(awaitResult()).isFalse()
+		}
+
+		withDatabase {
+			assertThat(it.branchQueries.selectAll().executeAsList().map { it.name })
+				.containsExactly("main")
+		}
+	}
 }