solana-install: check for fixed releases directly (#29365)

when initializing, if a specific release is requested, we only need to confirm it exists
this can be done with the download url itself, rather than pulling the list of releases

(cherry picked from commit 023509f)

install/src/command.rs

@@ -851,6 +851,11 @@ pub struct GithubRelease {
     pub prerelease: bool,
 }
 
+#[derive(Debug, Deserialize, Serialize)]
+pub struct GithubError {
+    pub message: String,
+}
+
 #[derive(Debug, Deserialize, Serialize)]
 pub struct GithubReleases(Vec<GithubRelease>);
 
@@ -864,14 +869,41 @@ fn semver_of(string: &str) -> Result<semver::Version, String> {
 }
 
 fn check_for_newer_github_release(
-    version_filter: Option<semver::VersionReq>,
+    current_release_semver: &str,
+    semver_update_type: SemverUpdateType,
     prerelease_allowed: bool,
-) -> reqwest::Result<Option<String>> {
-    let mut page = 1;
-    const PER_PAGE: usize = 100;
+) -> Result<Option<String>, String> {
     let client = reqwest::blocking::Client::builder()
         .user_agent("solana-install")
-        .build()?;
+        .build()
+        .map_err(|err| err.to_string())?;
+
+    // If we want a fixed version, we don't need to stress the API to check whether it exists
+    if semver_update_type == SemverUpdateType::Fixed {
+        let download_url = github_release_download_url(current_release_semver);
+        let response = client
+            .head(download_url.as_str())
+            .send()
+            .map_err(|err| err.to_string())?;
+
+        if response.status() == reqwest::StatusCode::OK {
+            return Ok(Some(current_release_semver.to_string()));
+        }
+    }
+
+    let version_filter = semver::VersionReq::parse(&format!(
+        "{}{}",
+        match semver_update_type {
+            SemverUpdateType::Fixed => "=",
+            SemverUpdateType::Patch => "~",
+            SemverUpdateType::_Minor => "^",
+        },
+        current_release_semver
+    ))
+    .ok();
+
+    let mut page = 1;
+    const PER_PAGE: usize = 100;
     let mut all_releases = vec![];
     let mut releases = vec![];
 
@@ -884,39 +916,48 @@ fn check_for_newer_github_release(
             ],
         )
         .unwrap();
-        let request = client.get(url).build()?;
-        let response = client.execute(request)?;
-
-        releases = response
-            .json::<GithubReleases>()?
-            .0
-            .into_iter()
-            .filter_map(
-                |GithubRelease {
-                     tag_name,
-                     prerelease,
-                 }| {
-                    if let Ok(version) = semver_of(&tag_name) {
-                        if (prerelease_allowed || !prerelease)
-                            && version_filter
-                                .as_ref()
-                                .map_or(true, |version_filter| version_filter.matches(&version))
-                        {
-                            return Some(version);
+        let request = client.get(url).build().map_err(|err| err.to_string())?;
+        let response = client.execute(request).map_err(|err| err.to_string())?;
+
+        if response.status() == reqwest::StatusCode::OK {
+            releases = response
+                .json::<GithubReleases>()
+                .map_err(|err| err.to_string())?
+                .0
+                .into_iter()
+                .filter_map(
+                    |GithubRelease {
+                         tag_name,
+                         prerelease,
+                     }| {
+                        if let Ok(version) = semver_of(&tag_name) {
+                            if (prerelease_allowed || !prerelease)
+                                && version_filter
+                                    .as_ref()
+                                    .map_or(true, |version_filter| version_filter.matches(&version))
+                            {
+                                return Some(version);
+                            }
                         }
-                    }
-                    None
-                },
-            )
-            .collect::<Vec<_>>();
-        all_releases.extend_from_slice(&releases);
-        page += 1;
+                        None
+                    },
+                )
+                .collect::<Vec<_>>();
+            all_releases.extend_from_slice(&releases);
+            page += 1;
+        } else {
+            return Err(response
+                .json::<GithubError>()
+                .map_err(|err| err.to_string())?
+                .message);
+        }
     }
 
     all_releases.sort();
     Ok(all_releases.pop().map(|r| r.to_string()))
 }
 
+#[derive(Debug, PartialEq, Eq)]
 pub enum SemverUpdateType {
     Fixed,
     Patch,
@@ -945,19 +986,11 @@ pub fn init_or_update(config_file: &str, is_init: bool, check_only: bool) -> Res
                 progress_bar.set_message(format!("{}Checking for updates...", LOOKING_GLASS));
 
                 let github_release = check_for_newer_github_release(
-                    semver::VersionReq::parse(&format!(
-                        "{}{}",
-                        match semver_update_type {
-                            SemverUpdateType::Fixed => "=",
-                            SemverUpdateType::Patch => "~",
-                            SemverUpdateType::_Minor => "^",
-                        },
-                        current_release_semver
-                    ))
-                    .ok(),
+                    current_release_semver,
+                    semver_update_type,
                     is_init,
-                )
-                .map_err(|err| err.to_string())?;
+                )?;
+
                 progress_bar.finish_and_clear();
 
                 match github_release {