Support default web process type

buildpacks/dotnet/CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Changed
+
+- The buildpack will now set the process type `web` for a single web application within a solution. When a solution contains multiple web applications, the process type is derived from the project assembly name. ([#242](https://github.com/heroku/buildpacks-dotnet/pull/242))
+
 ## [0.3.6] - 2025-03-20
 
 ### Changed

buildpacks/dotnet/src/launch_process.rs

@@ -2,6 +2,7 @@ use crate::dotnet::project::ProjectType;
 use crate::dotnet::solution::Solution;
 use crate::Project;
 use libcnb::data::launch::{Process, ProcessBuilder, ProcessType};
+use libcnb::data::process_type;
 use std::path::{Path, PathBuf};
 
 /// Detects processes in a solution's projects
@@ -25,7 +26,23 @@ fn project_launch_process(solution: &Solution, project: &Project) -> Option<Proc
 
     let command = build_command(&relative_executable_path, project.project_type);
 
-    Some(ProcessBuilder::new(project_process_type(project), ["bash", "-c", &command]).build())
+    let process_type = match project.project_type {
+        // If project is a web application, and there's only one web application in the solution,
+        // set the process type to `web`.
+        ProjectType::WebApplication
+            if solution
+                .projects
+                .iter()
+                .filter(|p| p.project_type == ProjectType::WebApplication)
+                .count()
+                == 1 =>
+        {
+            process_type!("web")
+        }
+        _ => project_process_type(project),
+    };
+
+    Some(ProcessBuilder::new(process_type, ["bash", "-c", &command]).build())
 }
 
 /// Constructs the shell command for launching the process
@@ -111,7 +128,7 @@ mod tests {
     }
 
     #[test]
-    fn test_detect_solution_processes_web_app() {
+    fn test_detect_solution_processes_single_web_app() {
         let solution = Solution {
             path: PathBuf::from("/tmp/foo.sln"),
             projects: vec![create_test_project(
@@ -122,7 +139,7 @@ mod tests {
         };
 
         let expected_processes = vec![Process {
-            r#type: process_type!("bar"),
+            r#type: process_type!("web"),
             command: vec![
                 "bash".to_string(),
                 "-c".to_string(),
@@ -136,6 +153,47 @@ mod tests {
         assert_eq!(detect_solution_processes(&solution), expected_processes);
     }
 
+    #[test]
+    fn test_detect_solution_processes_multiple_web_apps() {
+        let solution = Solution {
+            path: PathBuf::from("/tmp/foo.sln"),
+            projects: vec![
+                create_test_project("/tmp/bar/bar.csproj", "bar", ProjectType::WebApplication),
+                create_test_project("/tmp/baz/baz.csproj", "baz", ProjectType::WebApplication),
+            ],
+        };
+        assert_eq!(
+            detect_solution_processes(&solution)
+                .iter()
+                .map(|process| process.r#type.clone())
+                .collect::<Vec<ProcessType>>(),
+            vec![process_type!("bar"), process_type!("baz")]
+        );
+    }
+
+    #[test]
+    fn test_detect_solution_processes_single_web_app_and_console_app() {
+        let solution = Solution {
+            path: PathBuf::from("/tmp/foo.sln"),
+            projects: vec![
+                create_test_project("/tmp/qux/qux.csproj", "qux", ProjectType::Unknown),
+                create_test_project("/tmp/bar/bar.csproj", "bar", ProjectType::WebApplication),
+                create_test_project(
+                    "/tmp/baz/baz.csproj",
+                    "baz",
+                    ProjectType::ConsoleApplication,
+                ),
+            ],
+        };
+        assert_eq!(
+            detect_solution_processes(&solution)
+                .iter()
+                .map(|process| process.r#type.clone())
+                .collect::<Vec<ProcessType>>(),
+            vec![process_type!("web"), process_type!("baz")]
+        );
+    }
+
     #[test]
     fn test_detect_solution_processes_with_spaces() {
         let solution = Solution {

buildpacks/dotnet/tests/dotnet_publish_test.rs

@@ -100,7 +100,7 @@ fn test_dotnet_publish_process_registration_with_procfile() {
                 indoc! { r"
                     - Process types
                       - Detecting process types from published artifacts
-                      - Found `foo`: bash -c cd bin/publish; ./foo --urls http://*:$PORT
+                      - Found `web`: bash -c cd bin/publish; ./foo --urls http://*:$PORT
                       - Procfile detected
                       - Skipping process type registration (add process types to your Procfile as needed)"}
             );
@@ -120,7 +120,7 @@ fn test_dotnet_publish_process_registration_without_procfile() {
                 indoc! { r"
                 - Process types
                   - Detecting process types from published artifacts
-                  - Found `foo`: bash -c cd bin/publish; ./foo --urls http://*:$PORT
+                  - Found `web`: bash -c cd bin/publish; ./foo --urls http://*:$PORT
                   - No Procfile detected
                   - Registering detected process types as launch processes"}
             );