PY-81939: Do not show the full log on exec error dialog.

`PyError.message` contains the full log: all `orReturn("some text")` messages.

While they help user sometimes, some of them duplicate otuput and mustn't be displayed two times.

GitOrigin-RevId: 9a726cfcc8cb6b23825adc5d7dd505e1b8afd9c2

python/openapi/src/com/jetbrains/python/errorProcessing/ExecError.kt

@@ -25,7 +25,7 @@ class ExecError(
   /**
    * optional message to be displayed to the user: Why did we run this process. I.e "running pip to install package".
    */
-  additionalMessageToUser: @NlsContexts.DialogTitle String? = null,
+  val additionalMessageToUser: @NlsContexts.DialogTitle String? = null,
 ) : PyError(getExecErrorMessage(exe.toString(), args, additionalMessageToUser, errorReason)) {
   val asCommand: String get() = (arrayOf(exe.toString()) + args).joinToString(" ")
 }

python/openapi/src/com/jetbrains/python/errorProcessing/PyError.kt

@@ -18,7 +18,7 @@ import java.util.concurrent.CopyOnWriteArrayList
  */
 sealed class PyError(message: @NlsSafe String) {
   private val _messages = CopyOnWriteArrayList<@Nls String>(listOf(message))
-  val message: @Nls String get() = _messages.reversed().joinToString(": ")
+  val message: @Nls String get() = _messages.reversed().joinToString("\n")
 
   /**
    * To be used by [getOr], see it for more info

python/pluginResources/messages/PyBundle.properties

@@ -1589,6 +1589,7 @@ package.install.with.options.dialog.title=Package Install with Options
 python.toolwindow.packages.collapse.all.action=Collapse All
 django.template.language=Template Language
 python.error=Error
+python.error.full.log=See full error log
 
 action.UvSyncAction.text=uv Sync
 action.UvLockAction.text=uv Lock

python/src/com/jetbrains/python/ProcessExecutionErrorDialog.kt

@@ -57,7 +57,7 @@ fun showProcessExecutionErrorDialog(
 ) {
   check(project == null || !project.isDisposed)
 
-  val errorMessageText = execError.message + PyBundle.message("dialog.message.command.could.not.complete")
+  val errorMessageText = PyBundle.message("dialog.message.command.could.not.complete")
   // HTML format for text in `JBLabel` enables text wrapping
   val errorMessageLabel = JBLabel(UIUtil.toHtml(errorMessageText), Messages.getErrorIcon(), SwingConstants.LEFT)
 
@@ -89,12 +89,17 @@ fun showProcessExecutionErrorDialog(
 
   val formBuilder = FormBuilder()
     .addComponent(errorMessageLabel)
+    .addComponent(JButton(PyBundle.message("python.error.full.log")).apply {
+      addActionListener {
+        Messages.showErrorDialog(execError.message, PyBundle.message("python.error"))
+      }
+    })
     .addComponentFillVertically(commandOutputPanel, UIUtil.DEFAULT_VGAP)
 
   object : DialogWrapper(project) {
     init {
       init()
-      title = errorMessageText
+      title = execError.additionalMessageToUser ?: errorMessageText
     }
 
     override fun createActions(): Array<Action> = arrayOf(okAction)