fix: treat a chunked cut as a failed attempt

install.ps1

@@ -8,7 +8,7 @@ param(
 
 $ErrorActionPreference = "Stop"
 $defaultInstallUrl = "https://raw.githubusercontent.com/Abdess/retrobios/main/install.py"
-$defaultInstallSha256 = "ad00604f027af67f44fbb7dbe49513a870b6ba722263cf6a514df53cfe7ec13d"
+$defaultInstallSha256 = "0c3089832c2ee7e61b50a49edcd9a810814be8b5465238755b3954ff895c5e18"
 $maximumInstallerBytes = 2MB
 $installerExit = 0
 $installer = if ($PSScriptRoot) { Join-Path $PSScriptRoot "install.py" } else { $null }

install.py

@@ -1753,8 +1753,10 @@ def _fetch_json(url: str, limit: int, label: str) -> object:
             if exc.code < 500 and exc.code != 429 or attempt == MAX_RETRIES:
                 raise
             delay = _retry_delay(attempt, exc.headers.get("Retry-After") if exc.headers else None)
-        except (urllib.error.URLError, OSError):
+        except (urllib.error.URLError, OSError, http.client.HTTPException) as exc:
             if attempt == MAX_RETRIES:
+                if isinstance(exc, http.client.HTTPException):
+                    raise ConnectionError(f"connection cut: {exc!r}") from exc
                 raise
             delay = _retry_delay(attempt, None)
         time.sleep(delay)
@@ -2397,7 +2399,10 @@ def _download_one(
                 tmp_path.unlink()  # the partial copy no longer fits the file
             delay = _retry_delay(attempt, exc.headers.get("Retry-After") if exc.headers else None)
 
-        except (urllib.error.URLError, OSError, ValueError) as exc:
+        # http.client raises IncompleteRead (an HTTPException, not an
+        # OSError) when a chunked transfer is cut, as a proxy re-encoding
+        # the stream does: it is a dropped connection like any other.
+        except (urllib.error.URLError, OSError, ValueError, http.client.HTTPException) as exc:
             if (isinstance(exc, OSError) and not isinstance(exc, urllib.error.URLError)
                     and _write_refused(exc)):
                 # No attempt can change a refused write.
@@ -2749,9 +2754,9 @@ def _fetch_archive(url: str, directory: Path) -> Path:
             if exc.code < 500 and exc.code != 429:
                 raise
             reason = exc
-        except (urllib.error.URLError, OSError) as exc:
+        except (urllib.error.URLError, OSError, http.client.HTTPException) as exc:
             Path(handle.name).unlink(missing_ok=True)
-            reason = exc
+            reason = exc if isinstance(exc, OSError) else ConnectionError(repr(exc))
         except BaseException:
             Path(handle.name).unlink(missing_ok=True)
             raise

install.sh

@@ -18,7 +18,7 @@ esac
 TEMP_INSTALLER=""
 TEMP_DIRECTORY=""
 DEFAULT_INSTALL_URL="https://raw.githubusercontent.com/Abdess/retrobios/main/install.py"
-DEFAULT_INSTALL_SHA256="ad00604f027af67f44fbb7dbe49513a870b6ba722263cf6a514df53cfe7ec13d"
+DEFAULT_INSTALL_SHA256="0c3089832c2ee7e61b50a49edcd9a810814be8b5465238755b3954ff895c5e18"
 MAX_INSTALLER_BYTES=2097152
 
 cleanup() {

tests/test_install.py

@@ -2586,5 +2586,37 @@ class DataDirectoriesAreInstalled(unittest.TestCase):
         )
 
 
+
+class AChunkedCutIsADownloadFailure(unittest.TestCase):
+    """Behind a proxy that re-encodes as chunked, a cut raised
+    http.client.IncompleteRead, which no handler caught: the run ended on a
+    traceback with no summary."""
+
+    def test_the_file_fails_and_the_run_goes_on(self):
+        import http.client
+
+        class Cut:
+            headers = {}
+            status = 200
+
+            def __enter__(self):
+                return self
+
+            def __exit__(self, *exc):
+                return False
+
+            def read(self, *_args):
+                raise http.client.IncompleteRead(b"abc", 10)
+
+        entry = {"dest": "a.bin", "repo_path": "bios/a.bin", "size": 10,
+                 "sha1": "0" * 40, "sha256": "0" * 64}
+        with unittest.mock.patch.object(install.urllib.request, "urlopen",
+                                        lambda *a, **k: Cut()), \
+                unittest.mock.patch.object(install, "_retry_delay", return_value=0):
+            dest, ok, reason = install._download_one(entry, Path(_tempdir(self)))
+        self.assertFalse(ok)
+        self.assertIn("IncompleteRead", reason)
+
+
 if __name__ == "__main__":
     unittest.main()