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, 6 insertions, 3 deletions

diff --git a/crates/shirabe/src/util/perforce.rs b/crates/shirabe/src/util/perforce.rs
index 95cff0ca..295851c6 100644
--- a/crates/shirabe/src/util/perforce.rs
+++ b/crates/shirabe/src/util/perforce.rs
@@ -78,9 +78,12 @@ impl Perforce {
         Self::new(repo_config, port, path, process, Platform::is_windows(), io)
     }
 
-    pub fn check_server_exists(url: &str, process_executor: &mut ProcessExecutor) -> bool {
+    pub fn check_server_exists(
+        url: &str,
+        process_executor: &mut ProcessExecutor,
+    ) -> anyhow::Result<bool> {
         let mut ignored_output = String::new();
-        process_executor.execute_args(
+        Ok(process_executor.execute(
             &[
                 "p4".to_string(),
                 "-p".to_string(),
@@ -90,7 +93,7 @@ impl Perforce {
             ],
             &mut ignored_output,
             Option::<&str>::None,
-        ) == 0
+        )? == 0)
     }
 
     pub fn initialize(&mut self, repo_config: &IndexMap<String, PhpMixed>) {