fix: raise chained errors with "from" #998

This makes exceptions report their causes correctly, as "The above exception was
the direct cause of the following exception" instead of "During handling of the
above exception, another exception occurred."

1 files changed, 2 insertions, 2 deletions

diff --git a/coverage/sqldata.py b/coverage/sqldata.py
index 41542969..b2133026 100644
--- a/coverage/sqldata.py
+++ b/coverage/sqldata.py
@@ -291,7 +291,7 @@ class CoverageData(SimpleReprMixin):
                     "Data file {!r} doesn't seem to be a coverage data file: {}".format(
                         self._filename, exc
                     )
-                )
+                ) from exc
             else:
                 if schema_version != SCHEMA_VERSION:
                     raise CoverageException(
@@ -1095,7 +1095,7 @@ class SqliteDb(SimpleReprMixin):
                 pass
             if self.debug:
                 self.debug.write(f"EXCEPTION from execute: {msg}")
-            raise CoverageException(f"Couldn't use data file {self.filename!r}: {msg}")
+            raise CoverageException(f"Couldn't use data file {self.filename!r}: {msg}") from exc
 
     def execute_one(self, sql, parameters=()):
         """Execute a statement and return the one row that results.