Improve Git error message handling (#1011)

Co-authored-by: Harsh Shandilya <me@msfjarvis.dev>

app/src/main/java/com/zeapo/pwdstore/git/ErrorMessages.kt

@@ -6,58 +6,48 @@
 package com.zeapo.pwdstore.git
 
 import android.os.RemoteException
+import androidx.annotation.StringRes
 import com.zeapo.pwdstore.Application
 import com.zeapo.pwdstore.R
+import java.net.UnknownHostException
 
 /**
  * Supertype for all Git-related [Exception]s that can be thrown by [GitCommandExecutor.execute].
  */
-sealed class GitException(message: String? = null) : Exception(message) {
+sealed class GitException(@StringRes res: Int, vararg fmt: String) : Exception(buildMessage(res, *fmt)) {
+
+    override val message = super.message!!
+
+    companion object {
+        private fun buildMessage(@StringRes res: Int, vararg fmt: String) = Application.instance.resources.getString(res, *fmt)
+    }
 
     /**
      * Encapsulates possible errors from a [org.eclipse.jgit.api.PullCommand].
      */
-    class PullException(val reason: Reason) : GitException() {
+    sealed class PullException(@StringRes res: Int, vararg fmt: String) : GitException(res, *fmt) {
-
+        object PullRebaseFailed : PullException(R.string.git_pull_fail_error)
-        enum class Reason {
-            REBASE_FAILED,
-        }
     }
 
     /**
      * Encapsulates possible errors from a [org.eclipse.jgit.api.PushCommand].
      */
-    class PushException(val reason: Reason, vararg val fmt: String) : GitException() {
+    sealed class PushException(@StringRes res: Int, vararg fmt: String) : GitException(res, *fmt) {
-        enum class Reason {
+
-            NON_FAST_FORWARD,
+        object NonFastForward : PushException(R.string.git_push_nff_error)
-            REMOTE_REJECTED,
+        object RemoteRejected : PushException(R.string.git_push_other_error)
-            GENERIC,
+        class Generic(message: String) : PushException(R.string.git_push_generic_error, message)
-        }
     }
 }
 
 object ErrorMessages {
 
-    private val PULL_REASON_MAP = mapOf(
-        GitException.PullException.Reason.REBASE_FAILED to R.string.git_pull_fail_error,
-    )
-
-    private val PUSH_REASON_MAP = mapOf(
-        GitException.PushException.Reason.NON_FAST_FORWARD to R.string.git_push_nff_error,
-        GitException.PushException.Reason.REMOTE_REJECTED to R.string.git_push_other_error,
-        GitException.PushException.Reason.GENERIC to R.string.git_push_generic_error,
-    )
-
     operator fun get(throwable: Throwable?): String {
         val resources = Application.instance.resources
         if (throwable == null) return resources.getString(R.string.git_unknown_error)
         return when (val rootCause = rootCause(throwable)) {
-            is GitException.PullException -> {
+            is GitException -> rootCause.message
-                resources.getString(PULL_REASON_MAP.getValue(rootCause.reason))
+            is UnknownHostException -> resources.getString(R.string.git_unknown_host, throwable.message)
-            }
-            is GitException.PushException -> {
-                resources.getString(PUSH_REASON_MAP.getValue(rootCause.reason), *rootCause.fmt)
-            }
             else -> throwable.message ?: resources.getString(R.string.git_unknown_error)
         }
     }

app/src/main/java/com/zeapo/pwdstore/git/GitCommandExecutor.kt

@@ -59,7 +59,7 @@ class GitCommandExecutor(
                         }
                         val rr = result.rebaseResult
                         if (rr.status === RebaseResult.Status.STOPPED) {
-                            operationResult = Result.Err(PullException(PullException.Reason.REBASE_FAILED))
+                            operationResult = Result.Err(PullException.PullRebaseFailed)
                         }
                     }
                     is PushCommand -> {
@@ -70,21 +70,17 @@ class GitCommandExecutor(
                             // Code imported (modified) from Gerrit PushOp, license Apache v2
                             for (rru in result.remoteUpdates) {
                                 val error = when (rru.status) {
-                                    RemoteRefUpdate.Status.REJECTED_NONFASTFORWARD -> {
+                                    RemoteRefUpdate.Status.REJECTED_NONFASTFORWARD -> PushException.NonFastForward
-                                        PushException(PushException.Reason.NON_FAST_FORWARD)
-                                    }
                                     RemoteRefUpdate.Status.REJECTED_NODELETE,
                                     RemoteRefUpdate.Status.REJECTED_REMOTE_CHANGED,
                                     RemoteRefUpdate.Status.NON_EXISTING,
                                     RemoteRefUpdate.Status.NOT_ATTEMPTED,
-                                    -> {
+                                    -> PushException.Generic(rru.status.name)
-                                        PushException(PushException.Reason.GENERIC, rru.status.name)
-                                    }
                                     RemoteRefUpdate.Status.REJECTED_OTHER_REASON -> {
                                         if ("non-fast-forward" == rru.message) {
-                                            PushException(PushException.Reason.REMOTE_REJECTED)
+                                            PushException.RemoteRejected
                                         } else {
-                                            PushException(PushException.Reason.GENERIC, rru.message)
+                                            PushException.Generic(rru.message)
                                         }
                                     }
                                     RemoteRefUpdate.Status.UP_TO_DATE -> {

app/src/main/res/values/strings.xml

@@ -374,6 +374,7 @@
     <string name="git_push_nff_error">Push was rejected by remote, run pull before pushing again. You can use Synchronize rather than pull/push as it implements both</string>
     <string name="git_push_generic_error">Push was rejected by remote, reason: %1$s</string>
     <string name="git_push_other_error">Remote rejected non-fast-forward push. Check receive.denyNonFastForwards variable in config file of destination repository.</string>
+    <string name="git_unknown_host">Unknown host: %1$s</string>
     <string name="git_operation_running">Running git operation…</string>
 
     <!-- OpenKeychain not installed -->