Omit changes query parameter in CreateImageOptions if Vec is empty

src/image.rs

@@ -68,7 +68,10 @@ where
     pub platform: T,
     /// A list of Dockerfile instructions to be applied to the image being created. Changes must be
     /// URL-encoded! This parameter may only be used when importing an image.
-    #[serde(serialize_with = "crate::docker::serialize_join_newlines")]
+    #[serde(
+        serialize_with = "crate::docker::serialize_join_newlines",
+        skip_serializing_if = "Vec::is_empty" // if an empty changes parameter is sent, Docker returns a 400 "file with no instructions" error
+    )]
     pub changes: Vec<&'a str>,
 }
 
@@ -1470,7 +1473,7 @@ mod tests {
     async fn test_build_image_with_error() {
         let mut connector = HostToReplyConnector::default();
         connector.m.insert(
-            String::from("http://127.0.0.1"), 
+            String::from("http://127.0.0.1"),
             "HTTP/1.1 200 OK\r\nServer:mock1\r\nContent-Type:application/json\r\n\r\n{\"stream\":\"Step 1/2 : FROM alpine\"}\n{\"stream\":\"\n\"}\n{\"status\":\"Pulling from library/alpine\",\"id\":\"latest\"}\n{\"status\":\"Digest: sha256:bc41182d7ef5ffc53a40b044e725193bc10142a1243f395ee852a8d9730fc2ad\"}\n{\"status\":\"Status: Image is up to date for alpine:latest\"}\n{\"stream\":\" --- 9c6f07244728\\n\"}\n{\"stream\":\"Step 2/2 : RUN cmd.exe /C copy nul bollard.txt\"}\n{\"stream\":\"\\n\"}\n{\"stream\":\" --- Running in d615794caf91\\n\"}\n{\"stream\":\"/bin/sh: cmd.exe: not found\\n\"}\n{\"errorDetail\":{\"code\":127,\"message\":\"The command '/bin/sh -c cmd.exe /C copy nul bollard.txt' returned a non-zero code: 127\"},\"error\":\"The command '/bin/sh -c cmd.exe /C copy nul bollard.txt' returned a non-zero code: 127\"}".to_string());
         let docker =
             Docker::connect_with_mock(connector, "127.0.0.1".to_string(), 5, API_DEFAULT_VERSION)

tests/image_test.rs

@@ -27,6 +27,47 @@ async fn create_image_test(docker: Docker) -> Result<(), Error> {
     Ok(())
 }
 
+async fn create_image_wasm_test(docker: Docker) -> Result<(), Error> {
+    let image = "empty-wasm:latest";
+
+    let options = CreateImageOptions {
+        from_src: "-", // from_src must be "-" when sending the archive in the request body
+        repo: image,
+        ..Default::default()
+    };
+
+    let req_body = hyper::body::Body::from({
+        let mut buffer = Vec::new();
+
+        {
+            let mut builder = tar::Builder::new(&mut buffer);
+            let mut header = tar::Header::new_gnu();
+            header.set_path("entrypoint.wasm")?;
+            header.set_size(0);
+            header.set_cksum();
+
+            builder.append_data(&mut header, "entrypoint.wasm", [].as_slice())?;
+            builder.finish()?;
+        }
+
+        buffer
+    });
+
+    docker
+        .create_image(Some(options), Some(req_body), None)
+        .collect::<Vec<_>>()
+        .await
+        .into_iter()
+        .collect::<Result<Vec<_>, bollard::errors::Error>>()
+        .unwrap();
+
+    let result = &docker.inspect_image(image).await?;
+
+    assert!(result.repo_tags.as_ref().unwrap() == [image.to_owned()].as_slice());
+
+    Ok(())
+}
+
 async fn search_images_test(docker: Docker) -> Result<(), Error> {
     let result = &docker
         .search_images(SearchImagesOptions {
@@ -644,7 +685,7 @@ RUN apt-get update && \
         xutils-dev \
         gcc-multilib-arm-linux-gnueabihf \
         && \
-    apt-get clean && rm -rf /var/lib/apt/lists/* 
+    apt-get clean && rm -rf /var/lib/apt/lists/*
 ";
     let mut header = tar::Header::new_gnu();
     header.set_path("Dockerfile").unwrap();
@@ -731,6 +772,7 @@ async fn import_image_test(docker: Docker) -> Result<(), Error> {
 
     Ok(())
 }
+
 // ND - Test sometimes hangs on appveyor.
 #[cfg(not(windows))]
 #[test]
@@ -743,6 +785,12 @@ fn integration_test_create_image() {
     connect_to_docker_and_run!(create_image_test);
 }
 
+#[test]
+#[cfg(unix)]
+fn integration_test_create_image_wasm() {
+    connect_to_docker_and_run!(create_image_wasm_test);
+}
+
 #[test]
 // ND - Test sometimes hangs on appveyor.
 #[cfg(not(windows))]