fix(node): resolve issue ids from git refnames, not request input

crates/gitlawb-node/src/git/issues.rs

@@ -141,19 +141,10 @@ pub fn resolve_issue_id(repo_path: &Path, id_or_prefix: &str) -> Result<Option<S
         return Ok(None);
     }
 
-    // Try exact match first — fast path for callers passing the full UUID.
+    // List all refs that start with the given string; the glob also matches the exact
+    // ref. The id handed back is always git's own refname, never the request input.
     let exact_ref = format!("refs/gitlawb/issues/{id_or_prefix}");
-    let check = Command::new("git")
-        .args(["cat-file", "-e", &exact_ref])
-        .current_dir(repo_path)
-        .output()
-        .context("failed to run git cat-file -e")?;
-    if check.status.success() {
-        return Ok(Some(id_or_prefix.to_string()));
-    }
-
-    // Prefix search: list all refs that start with the given string.
-    let prefix_glob = format!("refs/gitlawb/issues/{id_or_prefix}*");
+    let prefix_glob = format!("{exact_ref}*");
     let list = Command::new("git")
         .args(["for-each-ref", "--format=%(refname)", &prefix_glob])
         .current_dir(repo_path)
@@ -165,25 +156,44 @@ pub fn resolve_issue_id(repo_path: &Path, id_or_prefix: &str) -> Result<Option<S
     }
 
     let output = String::from_utf8_lossy(&list.stdout);
-    let matches: Vec<&str> = output.lines().filter(|l| !l.trim().is_empty()).collect();
-
-    match matches.len() {
-        0 => Ok(None),
-        1 => {
-            // Strip the "refs/gitlawb/issues/" prefix to get the bare ID.
-            let full_id = matches[0]
-                .trim()
-                .strip_prefix("refs/gitlawb/issues/")
-                .unwrap_or(matches[0].trim())
-                .to_string();
-            Ok(Some(full_id))
+    let matches: Vec<&str> = output
+        .lines()
+        .map(str::trim)
+        .filter(|l| !l.is_empty())
+        .collect();
+
+    // An exact id wins over longer ids that share it as a prefix, but only if its
+    // object exists: for-each-ref also lists a ref whose blob is missing, so a
+    // dangling exact ref falls through to the prefix rules below.
+    let exact = match matches.iter().find(|m| **m == exact_ref) {
+        Some(m) => {
+            let check = Command::new("git")
+                .args(["cat-file", "-e", m])
+                .current_dir(repo_path)
+                .output()
+                .context("failed to run git cat-file -e")?;
+            check.status.success().then_some(*m)
         }
-        _ => anyhow::bail!(
-            "ambiguous issue prefix '{}': matches {} issues",
-            id_or_prefix,
-            matches.len()
-        ),
-    }
+        None => None,
+    };
+    let found = match exact {
+        Some(m) => m,
+        None => match matches.as_slice() {
+            [] => return Ok(None),
+            [m] => *m,
+            _ => anyhow::bail!(
+                "ambiguous issue prefix '{}': matches {} issues",
+                id_or_prefix,
+                matches.len()
+            ),
+        },
+    };
+    // Strip the "refs/gitlawb/issues/" prefix to get the bare ID.
+    let full_id = found
+        .strip_prefix("refs/gitlawb/issues/")
+        .unwrap_or(found)
+        .to_string();
+    Ok(Some(full_id))
 }
 
 /// Close an issue by updating its status to "closed" in the git ref.
@@ -267,6 +277,43 @@ mod tests {
         assert_eq!(resolved, Some(full_id.to_string()));
     }
 
+    #[test]
+    fn test_resolve_exact_id_wins_over_longer_id() {
+        let dir = TempDir::new().unwrap();
+        init_repo(&dir);
+        create_issue(dir.path(), "abc12345", r#"{"status":"open"}"#).unwrap();
+        create_issue(dir.path(), "abc12345-0000", r#"{"status":"open"}"#).unwrap();
+        let resolved = resolve_issue_id(dir.path(), "abc12345").unwrap();
+        assert_eq!(resolved, Some("abc12345".to_string()));
+    }
+
+    #[test]
+    fn test_resolve_dangling_exact_id_does_not_win_over_longer_id() {
+        let dir = TempDir::new().unwrap();
+        init_repo(&dir);
+        create_issue(dir.path(), "abc12345", r#"{"status":"open","n":1}"#).unwrap();
+        create_issue(dir.path(), "abc12345-0000", r#"{"status":"open","n":2}"#).unwrap();
+        // Dangle the exact ref: the ref stays listed by for-each-ref, but its blob is gone.
+        let out = Command::new("git")
+            .args(["rev-parse", "refs/gitlawb/issues/abc12345"])
+            .current_dir(dir.path())
+            .output()
+            .unwrap();
+        let hash = String::from_utf8(out.stdout).unwrap();
+        let hash = hash.trim();
+        std::fs::remove_file(
+            dir.path()
+                .join(".git/objects")
+                .join(&hash[..2])
+                .join(&hash[2..]),
+        )
+        .unwrap();
+
+        let result = resolve_issue_id(dir.path(), "abc12345");
+        assert!(result.unwrap_err().to_string().contains("ambiguous"));
+        assert!(close_issue(dir.path(), "abc12345").is_err());
+    }
+
     #[test]
     fn test_resolve_prefix_matches_unique() {
         let dir = TempDir::new().unwrap();