From 80f9c2a8888260cbf2e737f819605f1f05dbccbc Mon Sep 17 00:00:00 2001
From: maxonfjvipon <mtrunnikov@gmail.com>
Date: Fri, 15 Mar 2024 12:17:15 +0300
Subject: [PATCH] fix(#2938): exception

---
 .../main/java/org/eolang/maven/PhiMojo.java   | 44 ++++++++++++++++---
 1 file changed, 37 insertions(+), 7 deletions(-)

diff --git a/eo-maven-plugin/src/main/java/org/eolang/maven/PhiMojo.java b/eo-maven-plugin/src/main/java/org/eolang/maven/PhiMojo.java
index 095a6ed43f..0ececf9bd4 100644
--- a/eo-maven-plugin/src/main/java/org/eolang/maven/PhiMojo.java
+++ b/eo-maven-plugin/src/main/java/org/eolang/maven/PhiMojo.java
@@ -34,6 +34,7 @@
 import java.io.File;
 import java.nio.file.Path;
 import java.nio.file.Paths;
+import java.util.List;
 import org.apache.maven.plugins.annotations.LifecyclePhase;
 import org.apache.maven.plugins.annotations.Mojo;
 import org.apache.maven.plugins.annotations.Parameter;
@@ -124,7 +125,19 @@ public void exec() {
                                 String.format(".%s", PhiMojo.EXT)
                             )
                         );
-                        home.save(PhiMojo.translated(train, xml), relative);
+                        try {
+                            home.save(PhiMojo.translated(train, xml), relative);
+                        } catch (final ImpossibleToPhiTranslationException exception) {
+                            Logger.error(
+                                this,
+                                "XML is not translatable to phi:\n%s",
+                                xml.toString()
+                            );
+                            throw new IllegalStateException(
+                                String.format("Couldn't translate %s to phi", processed),
+                                exception
+                            );
+                        }
                         Logger.info(
                             this,
                             "Translated to phi: %[file]s (%[size]s) -> %[file]s (%[size]s)",
@@ -158,12 +171,29 @@ count, new Rel(this.phiInputDir), new Rel(this.phiOutputDir)
      * @param xmir Text of xmir
      * @return Translated xmir
      */
-    private static String translated(final Train<Shift> train, final XML xmir) {
-        return new Xsline(
+    private static String translated(final Train<Shift> train, final XML xmir) throws ImpossibleToPhiTranslationException {
+        final List<String> translated = new Xsline(
             train.with(new StClasspath("/org/eolang/maven/phi/to-phi.xsl"))
-        )
-            .pass(xmir)
-            .xpath("phi/text()")
-            .get(0);
+        ).pass(xmir).xpath("phi/text()");
+        if (translated.isEmpty()) {
+            throw new ImpossibleToPhiTranslationException(
+                "Xpath 'phi/text()' is not found in translated XMIR"
+            );
+        }
+        return translated.get(0);
+    }
+
+    /**
+     * Exception which indicates that translation to phi can't be processed.
+     * @since 0.36.0
+     */
+    static class ImpossibleToPhiTranslationException extends Exception {
+        /**
+         * Ctor.
+         * @param cause Cause of the exception.
+         */
+        ImpossibleToPhiTranslationException(final String cause) {
+            super(cause);
+        }
     }
 }