fix: propagate ported exceptions instead of flattening them

`ProcessExecutor::execute_args` existed only to turn `execute`'s
`anyhow::Result` into an exit code of 1, so every one of its ~87 call
sites silently took the "command failed" branch on an error PHP would
have thrown. It is gone; callers use `execute` and propagate with `?`.
Where the enclosing function had no `Result` to propagate into, its
signature grew one, up to and including `Git::get_version`,
`Svn::binary_version`, `GitHub`/`GitLab`/`Bitbucket::authorize_oauth`,
`InitCommand::get_git_config` and `DiagnoseCommand::check_git`.

The VCS drivers had the same problem in the other direction: their
`get_contents` returned `Result<Response, Box<TransportException>>`, a
type too narrow for the PHP method, which lets any Throwable out of the
`catch (TransportException $e)` block. Every non-transport error was
therefore rewritten into a `TransportException` with code 0, which the
callers switch on. They now return
`anyhow::Result<Result<Response, Box<TransportException>>>`: the outer
`Result` carries what PHP does not catch, the inner one the exception
the drivers handle.

That signature also restores `GitLabDriver::getContents`: the 400/401
`TransportException`s it raises to force authentication are thrown
inside its own `try` block and handled by its own `catch`, but the port
returned them straight to the caller, so the authentication flow behind
them never ran.

`impl_php_exception!` gains `From<Box<$ty>> for anyhow::Error` so a
caught exception can be re-propagated with `?`.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

1 files changed, 7 insertions, 3 deletions

diff --git a/crates/shirabe/tests/util/bitbucket_test.rs b/crates/shirabe/tests/util/bitbucket_test.rs
index e0fb9ef2..19641fed 100644
--- a/crates/shirabe/tests/util/bitbucket_test.rs
+++ b/crates/shirabe/tests/util/bitbucket_test.rs
@@ -555,7 +555,11 @@ fn test_get_token_without_access_token() {
 fn test_authorize_oauth_with_wrong_origin_url() {
     let config = ConfigStubBuilder::new().build_shared();
     let mut f = set_up_with_config_and_http(config, vec![]);
-    assert!(!f.bitbucket.authorize_oauth(&format!("non-{}", ORIGIN)));
+    assert!(
+        !f.bitbucket
+            .authorize_oauth(&format!("non-{}", ORIGIN))
+            .unwrap()
+    );
 }
 
 #[test]
@@ -578,7 +582,7 @@ fn test_authorize_oauth_without_available_git_config_token() {
     let mut bitbucket =
         Bitbucket::new(io, config, Some(process), Some(http_downloader), Some(time)).unwrap();
 
-    assert!(!bitbucket.authorize_oauth(ORIGIN));
+    assert!(!bitbucket.authorize_oauth(ORIGIN).unwrap());
 }
 
 #[test]
@@ -595,5 +599,5 @@ fn test_authorize_oauth_with_available_git_config_token() {
     let mut bitbucket =
         Bitbucket::new(io, config, Some(process), Some(http_downloader), Some(time)).unwrap();
 
-    assert!(bitbucket.authorize_oauth(ORIGIN));
+    assert!(bitbucket.authorize_oauth(ORIGIN).unwrap());
 }