feat(x2a): git auth credentials (#2839)

The e62d73d added a way to use auth url, but when the token has any illegal character for the URL, it fails to se the auth URL.

This change get the Auth Token, set the username (by backstage) and the token and it uses credentials helper for setting the commit.

Signed-off-by: Eloy Coto <eloy.coto@acalustra.com>

Author: eloycoto

workspaces/x2a/plugins/x2a-backend/templates/x2a-job-script.sh

@@ -110,20 +110,23 @@ run_x2a() {
   ERROR_MESSAGE=""
 }
 
-# Authenticated git wrappers.
-# Use url.<auth>.insteadOf to inject the token at the transport layer only.
-# The -c flag is transient (applies only to that git invocation), so the
-# token never appears in remote URLs, git config, or generated files like
-# Policyfile.lock.json. This works across GitHub, GitLab, and Bitbucket
-# because git natively handles the https://token@host URL format.
+# Authenticated git wrappers using credential helper.
+# Backstage provides tokens in format "username:password" where:
+# - GitHub:    "git:token"           (username is ignored, token is used)
+# - GitLab:    "oauth2:token"        (username oauth2, token is the actual token)
+# - Bitbucket: "x-token-auth:token"  (username x-token-auth, token is the actual token)
 git_source_repo() {
-  local auth_url="https://${SOURCE_REPO_TOKEN}@${SOURCE_REPO_URL#https://}"
-  git -c "url.${auth_url}.insteadOf=${SOURCE_REPO_URL}" "$@"
+  local username="${SOURCE_REPO_TOKEN%%:*}"
+  local password="${SOURCE_REPO_TOKEN#*:}"
+
+  git -c "credential.helper=!f() { test \"\$1\" = get && printf 'username=${username}\\npassword=${password}\\n'; }; f" "$@"
 }
 
 git_target_repo() {
-  local auth_url="https://${TARGET_REPO_TOKEN}@${TARGET_REPO_URL#https://}"
-  git -c "url.${auth_url}.insteadOf=${TARGET_REPO_URL}" "$@"
+  local username="${TARGET_REPO_TOKEN%%:*}"
+  local password="${TARGET_REPO_TOKEN#*:}"
+
+  git -c "credential.helper=!f() { test \"\$1\" = get && printf 'username=${username}\\npassword=${password}\\n'; }; f" "$@"
 }
 
 # Cleanup trap: fires on every exit (success or failure).