Additional error handling

src/main/java/org/openrewrite/dotnet/UpgradeAssistant.java

@@ -64,9 +64,12 @@ public List<String> buildUpgradeAssistantCommand(Accumulator acc, ExecutionConte
 
     @Override
     public void runUpgradeAssistant(Accumulator acc, ExecutionContext ctx) {
-        for (Path projectFile : acc.getProjectFiles()) {
+        List<Path> projectFiles = acc.getProjectFiles();
+        if (projectFiles.isEmpty()) {
+            throw new IllegalStateException("No project files found in repository");
+        }
+        for (Path projectFile : projectFiles) {
             execUpgradeAssistant(projectFile, acc, ctx);
-
         }
     }
 

src/main/java/org/openrewrite/dotnet/UpgradeAssistantAnalyze.java

@@ -22,11 +22,12 @@
 import org.jspecify.annotations.Nullable;
 import org.openrewrite.ExecutionContext;
 import org.openrewrite.Option;
-import org.openrewrite.RecipeException;
 import org.openrewrite.SourceFile;
 
 import java.io.IOException;
+import java.io.UncheckedIOException;
 import java.net.URL;
+import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.*;
@@ -122,7 +123,13 @@ protected void processOutput(Path solutionFile, Path output, Accumulator acc) {
                 }
             }
         } catch (IOException e) {
-            throw new RecipeException(e);
+            try {
+                throw new UncheckedIOException(
+                        e.getMessage() + "\nupgrade-assistant:\n" + new String(Files.readAllBytes(output)),
+                        e);
+            } catch (IOException ignored) {
+                throw new UncheckedIOException(e);
+            }
         }
     }
 

src/main/java/org/openrewrite/dotnet/UpgradeAssistantRecipe.java

@@ -27,6 +27,7 @@
 import org.openrewrite.text.PlainText;
 import org.openrewrite.tree.ParseError;
 
+import java.io.BufferedReader;
 import java.io.File;
 import java.io.IOException;
 import java.io.UncheckedIOException;
@@ -95,7 +96,6 @@ public Collection<? extends SourceFile> generate(Accumulator acc, ExecutionConte
     protected void execUpgradeAssistant(Path inputFile, Accumulator acc, ExecutionContext ctx) {
         List<String> command = buildUpgradeAssistantCommand(acc, ctx, inputFile);
         Path out = null;
-        Path err = null;
 
         try {
             ProcessBuilder builder = new ProcessBuilder();
@@ -108,37 +108,39 @@ protected void execUpgradeAssistant(Path inputFile, Accumulator acc, ExecutionCo
                     WorkingDirectoryExecutionContextView.view(ctx).getWorkingDirectory(),
                     UPGRADE_ASSISTANT,
                     null);
-            err = Files.createTempFile(
-                    WorkingDirectoryExecutionContextView.view(ctx).getWorkingDirectory(),
-                    UPGRADE_ASSISTANT,
-                    null);
+
             builder.redirectOutput(ProcessBuilder.Redirect.to(out.toFile()));
-            builder.redirectError(ProcessBuilder.Redirect.to(err.toFile()));
+            builder.redirectError(ProcessBuilder.Redirect.to(out.toFile()));
 
             Process process = builder.start();
             process.waitFor(20, TimeUnit.MINUTES);
-            if (process.exitValue() != 0) {
-                String error = "Command failed: " + String.join(" ", command);
-                if (Files.exists(err)) {
-                    error += "\n" + new String(Files.readAllBytes(err));
-                }
-                throw new RuntimeException(error);
-            } else {
-                for (Map.Entry<Path, Long> entry : acc.beforeModificationTimestamps.entrySet()) {
-                    Path path = entry.getKey();
-                    if (!Files.exists(path) || Files.getLastModifiedTime(path).toMillis() > entry.getValue()) {
-                        acc.addModifiedFile(path);
+
+            // upgrade-assistent currently does not exit with non-zero on error nor does it
+            // log errors to stderr. Here we look for known fatal errors in stdout suggesting
+            // the command failed.
+            if (Files.exists(out)) {
+                try (BufferedReader reader = Files.newBufferedReader(out)) {
+                    for (String line = reader.readLine(); line != null; line = reader.readLine()) {
+                        if (line.startsWith("Project path does not exist")) {
+                            throw new RuntimeException("upgrade-assistant: " + line);
+                        }
                     }
                 }
-                processOutput(inputFile, out, acc);
             }
+
+            for (Map.Entry<Path, Long> entry : acc.beforeModificationTimestamps.entrySet()) {
+                Path path = entry.getKey();
+                if (!Files.exists(path) || Files.getLastModifiedTime(path).toMillis() > entry.getValue()) {
+                    acc.addModifiedFile(path);
+                }
+            }
+            processOutput(inputFile, out, acc);
         } catch (IOException e) {
             throw new UncheckedIOException(e);
         } catch (InterruptedException e) {
             throw new RuntimeException(e);
         } finally {
             deleteFile(out);
-            deleteFile(err);
         }
     }
 

src/test/java/org/openrewrite/dotnet/UpgradeAssistantTest.java

@@ -108,21 +108,31 @@ void upgradeDotNetMultipleProject(String currentVersion, String upgradedVersion)
     @Test
     void upgradeDotNetWithInvalidVersion() {
         assertThatThrownBy(() ->
-                rewriteRun(
-                        spec -> spec.recipe(new UpgradeAssistant("foo-bar")),
-                        text(
-                                """
-                                        <Project Sdk="Microsoft.NET.Sdk">
-                                          <PropertyGroup>
-                                            <TargetFrameworks>net6.0</TargetFrameworks>
-                                          </PropertyGroup>
-                                        </Project>
-                                        """,
-                                spec -> spec.path("src/Proj.csproj")
-                        )
-                ))
-                .cause()
-                .isInstanceOf(RecipeException.class)
-                .hasMessageContaining("Unknown target framework");
+          rewriteRun(
+            spec -> spec.recipe(new UpgradeAssistant("foo-bar")),
+            text(
+              """
+                <Project Sdk="Microsoft.NET.Sdk">
+                  <PropertyGroup>
+                    <TargetFrameworks>net6.0</TargetFrameworks>
+                  </PropertyGroup>
+                </Project>
+                """,
+              spec -> spec.path("src/Proj.csproj")
+            )
+          ))
+          .cause()
+          .isInstanceOf(RecipeException.class)
+          .hasMessageContaining("Unknown target framework");
+    }
+
+    @Test
+    void upgradeDotNetWithNoProjectFiles() {
+        assertThatThrownBy(() ->
+          rewriteRun(
+            spec -> spec.recipe(new UpgradeAssistant("net9.0"))
+          ))
+          .isInstanceOf(IllegalStateException.class)
+          .hasMessageContaining("No project files found in repository");
     }
 }