feat(build): Add auto-detection of base_repo_name from git remote (#2735)

## Summary
Implements EME-232 to automatically detect `base_repo_name` for build
uploads when not explicitly provided by the user.

## Changes
- **Added `git_repo_base_repo_name()` function** in `src/utils/vcs.rs`
that:
  - Fetches the first available git remote from the repository
- Extracts the repository name using existing `get_repo_from_remote()`
function

🤖 Generated with [Claude Code](https://claude.ai/code)

Closes
https://linear.app/getsentry/issue/EME-232/sentry-cli-provide-default-value-for-base-repo-name-if-user-doesnt

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: runningcode

src/commands/build/upload.rs

@@ -25,7 +25,7 @@ use crate::utils::fs::TempFile;
 use crate::utils::progress::ProgressBar;
 use crate::utils::vcs::{
     self, get_github_pr_number, get_provider_from_remote, get_repo_from_remote, git_repo_base_ref,
-    git_repo_head_ref, git_repo_remote_url,
+    git_repo_base_repo_name, git_repo_head_ref, git_repo_remote_url,
 };
 
 pub fn make_command(command: Command) -> Command {
@@ -116,7 +116,7 @@ pub fn execute(matches: &ArgMatches) -> Result<()> {
 
     let cached_remote = config.get_cached_vcs_remote();
     // Try to open the git repository and find the remote, but handle errors gracefully.
-    let (vcs_provider, head_repo_name, head_ref, base_ref) = {
+    let (vcs_provider, head_repo_name, head_ref, base_ref, base_repo_name) = {
         // Try to open the repo and get the remote URL, but don't fail if not in a repo.
         let repo = git2::Repository::open_from_env().ok();
         let repo_ref = repo.as_ref();
@@ -191,10 +191,38 @@ pub fn execute(matches: &ArgMatches) -> Result<()> {
                     .map(Cow::Owned)
             });
 
-        (vcs_provider, head_repo_name, head_ref, base_ref)
-    };
+        let base_repo_name = matches
+            .get_one("base_repo_name")
+            .map(String::as_str)
+            .map(Cow::Borrowed)
+            .or_else(|| {
+                // Try to get the base repo name from the VCS if not provided
+                repo_ref
+                    .and_then(|r| match git_repo_base_repo_name(r) {
+                        Ok(Some(base_repo_name)) => {
+                            debug!("Found base repository name: {}", base_repo_name);
+                            Some(base_repo_name)
+                        }
+                        Ok(None) => {
+                            debug!("No base repository found - not a fork");
+                            None
+                        }
+                        Err(e) => {
+                            warn!("Could not detect base repository name: {}", e);
+                            None
+                        }
+                    })
+                    .map(Cow::Owned)
+            });
 
-    let base_repo_name = matches.get_one("base_repo_name").map(String::as_str);
+        (
+            vcs_provider,
+            head_repo_name,
+            head_ref,
+            base_ref,
+            base_repo_name,
+        )
+    };
     let base_sha = matches.get_one("base_sha").map(String::as_str);
     let pr_number = matches
         .get_one("pr_number")
@@ -261,7 +289,7 @@ pub fn execute(matches: &ArgMatches) -> Result<()> {
             base_sha,
             vcs_provider: vcs_provider.as_deref(),
             head_repo_name: head_repo_name.as_deref(),
-            base_repo_name,
+            base_repo_name: base_repo_name.as_deref(),
             head_ref: head_ref.as_deref(),
             base_ref: base_ref.as_deref(),
             pr_number: pr_number.as_ref(),

src/utils/vcs.rs

@@ -8,7 +8,7 @@ use chrono::{DateTime, FixedOffset, TimeZone as _};
 use git2::{Commit, Repository, Time};
 use if_chain::if_chain;
 use lazy_static::lazy_static;
-use log::{debug, info};
+use log::{debug, info, warn};
 use regex::Regex;
 
 use crate::api::{GitCommit, PatchSet, Ref, Repo};
@@ -283,6 +283,37 @@ fn find_merge_base_ref(
     Ok(merge_base_sha)
 }
 
+/// Attempts to get the base repository name from git remotes.
+/// Prefers "origin" remote if it exists, otherwise uses the first available remote.
+/// Returns the base repository name if a remote is found.
+pub fn git_repo_base_repo_name(repo: &git2::Repository) -> Result<Option<String>> {
+    let remotes = repo.remotes()?;
+    let remote_names: Vec<&str> = remotes.iter().flatten().collect();
+
+    if remote_names.is_empty() {
+        warn!("No remotes found in repository");
+        return Ok(None);
+    }
+
+    // Prefer "origin" remote if it exists, otherwise use the first one
+    let chosen_remote = if remote_names.contains(&"origin") {
+        "origin"
+    } else {
+        remote_names[0]
+    };
+
+    match git_repo_remote_url(repo, chosen_remote) {
+        Ok(remote_url) => {
+            debug!("Found remote '{}': {}", chosen_remote, remote_url);
+            Ok(Some(get_repo_from_remote(&remote_url)))
+        }
+        Err(e) => {
+            warn!("Could not get URL for remote '{}': {}", chosen_remote, e);
+            Ok(None)
+        }
+    }
+}
+
 /// Attempts to get the PR number from GitHub Actions environment variables.
 /// Returns the PR number if running in a GitHub Actions pull request environment.
 pub fn get_github_pr_number() -> Option<u32> {