fix: propagate exceptions in Bootstrapper._build_sdist to fail on sdist build errors

Previously, _build_sdist() would catch and log all exceptions, causing the build
to continue even if building the source distribution failed. This could result in
undefined or misleading behavior. Now, exceptions are allowed to propagate,
ensuring that build failures are reported and handled properly.

Fixes #637

Signed-off-by: Emilien Macchi <emacchi@redhat.com>

Author: EmilienM

src/fromager/bootstrapper.py

@@ -323,32 +323,20 @@ def _build_sdist(
         sdist_root_dir: pathlib.Path,
         build_env: build_environment.BuildEnvironment,
     ) -> pathlib.Path:
-        sdist_filename: pathlib.Path | None = None
-        try:
-            find_sdist_result = finders.find_sdist(
-                self.ctx, self.ctx.sdists_builds, req, str(resolved_version)
+        find_sdist_result = finders.find_sdist(
+            self.ctx, self.ctx.sdists_builds, req, str(resolved_version)
+        )
+        if not find_sdist_result:
+            sdist_filename = sources.build_sdist(
+                ctx=self.ctx,
+                req=req,
+                version=resolved_version,
+                sdist_root_dir=sdist_root_dir,
+                build_env=build_env,
             )
-            if not find_sdist_result:
-                sdist_filename = sources.build_sdist(
-                    ctx=self.ctx,
-                    req=req,
-                    version=resolved_version,
-                    sdist_root_dir=sdist_root_dir,
-                    build_env=build_env,
-                )
-            else:
-                sdist_filename = find_sdist_result
-                logger.info(
-                    f"have sdist version {resolved_version}: {find_sdist_result}"
-                )
-        except Exception as err:
-            logger.warning(f"failed to build source distribution: {err}")
-            # Re-raise the exception since we cannot continue without a sdist
-            raise
-
-        if sdist_filename is None:
-            raise RuntimeError(f"Failed to build or find sdist for {req}")
-
+        else:
+            sdist_filename = find_sdist_result
+            logger.info(f"have sdist version {resolved_version}: {find_sdist_result}")
         return sdist_filename
 
     def _build_wheel(