Merge pull request #131 from rust-lang/chore-improve-repo-read-error-message

fix: don't fail when reading a repo that doesn't exist

Author: marcoieni

src/github/api/mod.rs

@@ -92,7 +92,46 @@ impl HttpClient {
         }
     }
 
+    /// Send a request to the GitHub API and return the response.
     fn graphql<R, V>(&self, query: &str, variables: V, org: &str) -> anyhow::Result<R>
+    where
+        R: serde::de::DeserializeOwned,
+        V: serde::Serialize,
+    {
+        let res = self.send_graphql_req(query, variables, org)?;
+
+        if let Some(error) = res.errors.first() {
+            bail!("graphql error: {}", error.message);
+        }
+
+        read_graphql_data(res)
+    }
+
+    /// Send a request to the GitHub API and return the response.
+    /// If the request contains the error type `NOT_FOUND`, this method returns `Ok(None)`.
+    fn graphql_opt<R, V>(&self, query: &str, variables: V, org: &str) -> anyhow::Result<Option<R>>
+    where
+        R: serde::de::DeserializeOwned,
+        V: serde::Serialize,
+    {
+        let res = self.send_graphql_req(query, variables, org)?;
+
+        if let Some(error) = res.errors.first() {
+            if error.type_ == Some(GraphErrorType::NotFound) {
+                return Ok(None);
+            }
+            bail!("graphql error: {}", error.message);
+        }
+
+        read_graphql_data(res)
+    }
+
+    fn send_graphql_req<R, V>(
+        &self,
+        query: &str,
+        variables: V,
+        org: &str,
+    ) -> anyhow::Result<GraphResult<R>>
     where
         R: serde::de::DeserializeOwned,
         V: serde::Serialize,
@@ -105,19 +144,13 @@ impl HttpClient {
         let resp = self
             .req(Method::POST, &GitHubUrl::new("graphql", org))?
             .json(&Request { query, variables })
-            .send()?
+            .send()
+            .context("failed to send graphql request")?
             .custom_error_for_status()?;
 
-        let res: GraphResult<R> = resp.json_annotated().with_context(|| {
+        resp.json_annotated().with_context(|| {
             format!("Failed to decode response body on graphql request with query '{query}'")
-        })?;
-        if let Some(error) = res.errors.first() {
-            bail!("graphql error: {}", error.message);
-        } else if let Some(data) = res.data {
-            Ok(data)
-        } else {
-            bail!("missing graphql data");
-        }
+        })
     }
 
     fn rest_paginated<F, T>(&self, method: &Method, url: &GitHubUrl, mut f: F) -> anyhow::Result<()>
@@ -159,6 +192,17 @@ impl HttpClient {
     }
 }
 
+fn read_graphql_data<R>(res: GraphResult<R>) -> anyhow::Result<R>
+where
+    R: serde::de::DeserializeOwned,
+{
+    if let Some(data) = res.data {
+        Ok(data)
+    } else {
+        bail!("missing graphql data");
+    }
+}
+
 fn allow_not_found(resp: Response, method: Method, url: &str) -> Result<(), anyhow::Error> {
     match resp.status() {
         StatusCode::NOT_FOUND => {
@@ -180,9 +224,19 @@ struct GraphResult<T> {
 
 #[derive(Debug, serde::Deserialize)]
 struct GraphError {
+    #[serde(rename = "type")]
+    type_: Option<GraphErrorType>,
     message: String,
 }
 
+#[derive(Debug, serde::Deserialize, PartialEq, Eq)]
+#[serde(rename_all = "SCREAMING_SNAKE_CASE")]
+enum GraphErrorType {
+    NotFound,
+    #[serde(other)]
+    Other,
+}
+
 #[derive(serde::Deserialize)]
 struct GraphNodes<T> {
     nodes: Vec<Option<T>>,

src/github/api/read.rs

@@ -2,6 +2,7 @@ use crate::github::api::{
     BranchProtection, GraphNode, GraphNodes, GraphPageInfo, HttpClient, Login, Repo, RepoTeam,
     RepoUser, Team, TeamMember, TeamRole, team_node_id, url::GitHubUrl, user_node_id,
 };
+use anyhow::Context as _;
 use reqwest::Method;
 use std::collections::{HashMap, HashSet};
 
@@ -271,16 +272,19 @@ impl GithubRead for GitHubApiRead {
             is_archived: bool,
         }
 
-        let result: Wrapper = self.client.graphql(
-            QUERY,
-            Params {
-                owner: org,
-                name: repo,
-            },
-            org,
-        )?;
+        let result: Option<Wrapper> = self
+            .client
+            .graphql_opt(
+                QUERY,
+                Params {
+                    owner: org,
+                    name: repo,
+                },
+                org,
+            )
+            .with_context(|| format!("failed to retrieve repo `{org}/{repo}`"))?;
 
-        let repo = result.repository.map(|repo_response| Repo {
+        let repo = result.and_then(|r| r.repository).map(|repo_response| Repo {
             node_id: repo_response.id,
             name: repo.to_string(),
             description: repo_response.description.unwrap_or_default(),

src/utils.rs

@@ -13,8 +13,8 @@ impl ResponseExt for Response {
         match self.error_for_status_ref() {
             Ok(_) => Ok(self),
             Err(err) => {
-                let body = self.text()?;
-                Err(err).context(format!("Body: {:?}", body))
+                let body = self.text().context("failed to read response body")?;
+                Err(err).context(format!("Body: {body:?}"))
             }
         }
     }