Merge #3295

3295: Refactoring fetchArtifactReleaseInfo() r=matklad a=Veetaha

https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/no-unnecessary-type-assertion.md

I fact this rule doesn't work when you put an unnecessary non-null assertion in an expression (as we had `(awat f())!`, but it is useful in other cases...

Closes #3295, i guess...

Co-authored-by: Veetaha <gerzoh1@gmail.com>

3 files changed, 42 insertions, 21 deletions

diff --git a/editors/code/.eslintrc.js b/editors/code/.eslintrc.js
index 16f18ab2c2c..c6bf410f4b5 100644
--- a/editors/code/.eslintrc.js
+++ b/editors/code/.eslintrc.js
@@ -32,6 +32,7 @@ module.exports = {
         "@typescript-eslint/semi": [
             "error",
             "always"
-        ]
+        ],
+        "@typescript-eslint/no-unnecessary-type-assertion": "error"
     }
 };
diff --git a/editors/code/src/installation/fetch_artifact_release_info.ts b/editors/code/src/installation/fetch_artifact_release_info.ts
index 1b6fc8d48c0..b1b5a3485cc 100644
--- a/editors/code/src/installation/fetch_artifact_release_info.ts
+++ b/editors/code/src/installation/fetch_artifact_release_info.ts
@@ -4,41 +4,61 @@ import { log } from "../util";
 
 const GITHUB_API_ENDPOINT_URL = "https://api.github.com";
 
-
 /**
- * Fetches the release with `releaseTag` (or just latest release when not specified)
- * from GitHub `repo` and returns metadata about `artifactFileName` shipped with
- * this release or `null` if no such artifact was published.
+ * Fetches the release with `releaseTag` from GitHub `repo` and
+ * returns metadata about `artifactFileName` shipped with
+ * this release.
+ *
+ * @throws Error upon network failure or if no such repository, release, or artifact exists.
  */
 export async function fetchArtifactReleaseInfo(
-    repo: GithubRepo, artifactFileName: string, releaseTag?: string
-): Promise<null | ArtifactReleaseInfo> {
+    repo: GithubRepo,
+    artifactFileName: string,
+    releaseTag: string
+): Promise<ArtifactReleaseInfo> {
 
     const repoOwner = encodeURIComponent(repo.owner);
     const repoName = encodeURIComponent(repo.name);
 
-    const apiEndpointPath = releaseTag
-        ? `/repos/${repoOwner}/${repoName}/releases/tags/${releaseTag}`
-        : `/repos/${repoOwner}/${repoName}/releases/latest`;
+    const apiEndpointPath = `/repos/${repoOwner}/${repoName}/releases/tags/${releaseTag}`;
 
     const requestUrl = GITHUB_API_ENDPOINT_URL + apiEndpointPath;
 
-    // We skip runtime type checks for simplicity (here we cast from `any` to `GithubRelease`)
-
     log.debug("Issuing request for released artifacts metadata to", requestUrl);
 
-    // FIXME: handle non-ok response
-    const response: GithubRelease = await fetch(requestUrl, {
-        headers: { Accept: "application/vnd.github.v3+json" }
-    })
-        .then(res => res.json());
+    const response = await fetch(requestUrl, { headers: { Accept: "application/vnd.github.v3+json" } });
 
-    const artifact = response.assets.find(artifact => artifact.name === artifactFileName);
+    if (!response.ok) {
+        log.error("Error fetching artifact release info", {
+            requestUrl,
+            releaseTag,
+            artifactFileName,
+            response: {
+                headers: response.headers,
+                status: response.status,
+                body: await response.text(),
+            }
+        });
+
+        throw new Error(
+            `Got response ${response.status} when trying to fetch ` +
+            `"${artifactFileName}" artifact release info for ${releaseTag} release`
+        );
+    }
 
-    if (!artifact) return null;
+    // We skip runtime type checks for simplicity (here we cast from `any` to `GithubRelease`)
+    const release: GithubRelease = await response.json();
+
+    const artifact = release.assets.find(artifact => artifact.name === artifactFileName);
+
+    if (!artifact) {
+        throw new Error(
+            `Artifact ${artifactFileName} was not found in ${release.name} release!`
+        );
+    }
 
     return {
-        releaseName: response.name,
+        releaseName: release.name,
         downloadUrl: artifact.browser_download_url
     };
 
diff --git a/editors/code/src/installation/server.ts b/editors/code/src/installation/server.ts
index 9de257dd51b..cb5e568448a 100644
--- a/editors/code/src/installation/server.ts
+++ b/editors/code/src/installation/server.ts
@@ -63,7 +63,7 @@ export async function ensureServerBinary(source: null | BinarySource): Promise<n
 
 async function downloadServer(source: BinarySource.GithubRelease): Promise<boolean> {
     try {
-        const releaseInfo = (await fetchArtifactReleaseInfo(source.repo, source.file, source.version))!;
+        const releaseInfo = await fetchArtifactReleaseInfo(source.repo, source.file, source.version);
 
         await downloadArtifact(releaseInfo, source.file, source.dir, "language server");
         await setServerVersion(source.storage, releaseInfo.releaseName);