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Merged
rostilos merged 1 commit into from
Jan 5, 2026
Merged

changes -> diffs ( gitlab MR diff retrieval API changes ) #40

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96 changes: 70 additions & 26 deletions ...c/main/java/org/rostilos/codecrow/vcsclient/gitlab/actions/GetMergeRequestDiffAction.java
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Original file line number Diff line number Diff line change
Expand Up @@ -12,22 +12,29 @@
import java.io.IOException;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;

/**
* Action to get the diff for a GitLab Merge Request.
* Uses the /diffs endpoint (replaces deprecated /changes endpoint).
*
* @see <a href="https://docs.gitlab.com/ee/api/merge_requests.html#list-merge-request-diffs">GitLab API: List merge request diffs</a>
*/
public class GetMergeRequestDiffAction {

private static final Logger log = LoggerFactory.getLogger(GetMergeRequestDiffAction.class);
private static final ObjectMapper objectMapper = new ObjectMapper();
private static final int DEFAULT_PER_PAGE = 100;
private final OkHttpClient authorizedOkHttpClient;

public GetMergeRequestDiffAction(OkHttpClient authorizedOkHttpClient) {
this.authorizedOkHttpClient = authorizedOkHttpClient;
}

/**
* Get the diff for a merge request.
* Get the diff for a merge request using the /diffs endpoint.
* This endpoint returns paginated results, so we fetch all pages.
*
* @param namespace the project namespace (group or user)
* @param project the project path
Expand All @@ -38,44 +45,81 @@ public String getMergeRequestDiff(String namespace, String project, int mergeReq
String projectPath = namespace + "/" + project;
String encodedPath = URLEncoder.encode(projectPath, StandardCharsets.UTF_8);

// First, get the merge request changes (diffs)
String apiUrl = String.format("%s/projects/%s/merge_requests/%d/changes",
GitLabConfig.API_BASE, encodedPath, mergeRequestIid);
// Use the /diffs endpoint (replaces deprecated /changes endpoint)
// API: GET /projects/:id/merge_requests/:merge_request_iid/diffs
List<JsonNode> allDiffs = fetchAllDiffs(encodedPath, mergeRequestIid);

return buildUnifiedDiff(allDiffs);
}

/**
* Fetch all diffs with pagination support.
* The /diffs endpoint returns paginated results.
*/
private List<JsonNode> fetchAllDiffs(String encodedPath, int mergeRequestIid) throws IOException {
List<JsonNode> allDiffs = new ArrayList<>();
int page = 1;
boolean hasMore = true;

while (hasMore) {
String apiUrl = String.format("%s/projects/%s/merge_requests/%d/diffs?page=%d&per_page=%d",
GitLabConfig.API_BASE, encodedPath, mergeRequestIid, page, DEFAULT_PER_PAGE);

Request req = new Request.Builder()
.url(apiUrl)
.header("Accept", "application/json")
.get()
.build();
Request req = new Request.Builder()
.url(apiUrl)
.header("Accept", "application/json")
.get()
.build();

try (Response resp = authorizedOkHttpClient.newCall(req).execute()) {
if (!resp.isSuccessful()) {
String body = resp.body() != null ? resp.body().string() : "";
String msg = String.format("GitLab returned non-success response %d for URL %s: %s",
resp.code(), apiUrl, body);
log.warn(msg);
throw new IOException(msg);
try (Response resp = authorizedOkHttpClient.newCall(req).execute()) {
if (!resp.isSuccessful()) {
String body = resp.body() != null ? resp.body().string() : "";
String msg = String.format("GitLab returned non-success response %d for URL %s: %s",
resp.code(), apiUrl, body);
log.warn(msg);
throw new IOException(msg);
}

String responseBody = resp.body() != null ? resp.body().string() : "[]";
JsonNode diffsArray = objectMapper.readTree(responseBody);

if (!diffsArray.isArray() || diffsArray.isEmpty()) {
hasMore = false;
} else {
for (JsonNode diff : diffsArray) {
allDiffs.add(diff);
}

// Check if there are more pages
String totalPages = resp.header("X-Total-Pages");
if (totalPages != null) {
hasMore = page < Integer.parseInt(totalPages);
} else {
// If no pagination headers, assume no more pages if we got less than per_page
hasMore = diffsArray.size() >= DEFAULT_PER_PAGE;
}
page++;
}
}

String responseBody = resp.body() != null ? resp.body().string() : "{}";
return buildUnifiedDiff(responseBody);
}

log.debug("Fetched {} diffs for MR {}", allDiffs.size(), mergeRequestIid);
return allDiffs;
}

/**
* Build a unified diff from GitLab's changes response.
* Build a unified diff from GitLab's /diffs response.
* The /diffs endpoint returns an array of diff objects directly.
*/
private String buildUnifiedDiff(String responseBody) throws IOException {
private String buildUnifiedDiff(List<JsonNode> diffs) {
StringBuilder combinedDiff = new StringBuilder();
JsonNode root = objectMapper.readTree(responseBody);
JsonNode changes = root.get("changes");

if (changes == null || !changes.isArray()) {
log.warn("No changes found in merge request response");
if (diffs.isEmpty()) {
log.warn("No diffs found in merge request response");
return "";
}

for (JsonNode change : changes) {
for (JsonNode change : diffs) {
String oldPath = change.has("old_path") ? change.get("old_path").asText() : "";
String newPath = change.has("new_path") ? change.get("new_path").asText() : "";
String diff = change.has("diff") ? change.get("diff").asText() : "";
Expand Down