Fixed issue #433 - CLI eats cursor (#598)

The issue is that underlying iterator is not fully consumed within the body of
the `with file_progress()` block. Instead, that block creates generator
expressions like `docs = (dict(zip(headers, row)) for row in reader)`

These iterables are consumed later, outside the `with file_progress()` block,
which consumes the underlying iterator, and in turn updates the progress bar.

This means that the `ProgressBar.__exit__` method gets called before the last
time the `ProgressBar.update` method gets called. The result is that the code to
make the cursor invisible (inside the `update()` method) is called after the
cleanup code to make it visible (in the `__exit__` method).

The fix is to move consumption of the `docs` iterators within the progress bar block.

(An additional fix, to make ProgressBar more robust against this kind of misuse, would
to make it refusing to update after its `__exit__` method had been called, just
like files cannot be `read()` after they are closed. That requires a in the
click library).

sqlite_utils/cli.py

@@ -1024,93 +1024,97 @@ def insert_upsert_implementation(
             if flatten:
                 docs = (_flatten(doc) for doc in docs)
 
-    if stop_after:
-        docs = itertools.islice(docs, stop_after)
-
-    if convert:
-        variable = "row"
-        if lines:
-            variable = "line"
-        elif text:
-            variable = "text"
-        fn = _compile_code(convert, imports, variable=variable)
-        if lines:
-            docs = (fn(doc["line"]) for doc in docs)
-        elif text:
-            # Special case: this is allowed to be an iterable
-            text_value = list(docs)[0]["text"]
-            fn_return = fn(text_value)
-            if isinstance(fn_return, dict):
-                docs = [fn_return]
+        if stop_after:
+            docs = itertools.islice(docs, stop_after)
+
+        if convert:
+            variable = "row"
+            if lines:
+                variable = "line"
+            elif text:
+                variable = "text"
+            fn = _compile_code(convert, imports, variable=variable)
+            if lines:
+                docs = (fn(doc["line"]) for doc in docs)
+            elif text:
+                # Special case: this is allowed to be an iterable
+                text_value = list(docs)[0]["text"]
+                fn_return = fn(text_value)
+                if isinstance(fn_return, dict):
+                    docs = [fn_return]
+                else:
+                    try:
+                        docs = iter(fn_return)
+                    except TypeError:
+                        raise click.ClickException(
+                            "--convert must return dict or iterator"
+                        )
             else:
-                try:
-                    docs = iter(fn_return)
-                except TypeError:
-                    raise click.ClickException("--convert must return dict or iterator")
-        else:
-            docs = (fn(doc) or doc for doc in docs)
-
-    extra_kwargs = {
-        "ignore": ignore,
-        "replace": replace,
-        "truncate": truncate,
-        "analyze": analyze,
-    }
-    if not_null:
-        extra_kwargs["not_null"] = set(not_null)
-    if default:
-        extra_kwargs["defaults"] = dict(default)
-    if upsert:
-        extra_kwargs["upsert"] = upsert
-
-    # docs should all be dictionaries
-    docs = (verify_is_dict(doc) for doc in docs)
-
-    # Apply {"$base64": true, ...} decoding, if needed
-    docs = (decode_base64_values(doc) for doc in docs)
-
-    # For bulk_sql= we use cursor.executemany() instead
-    if bulk_sql:
-        if batch_size:
-            doc_chunks = chunks(docs, batch_size)
-        else:
-            doc_chunks = [docs]
-        for doc_chunk in doc_chunks:
-            with db.conn:
-                db.conn.cursor().executemany(bulk_sql, doc_chunk)
-        return
+                docs = (fn(doc) or doc for doc in docs)
+
+        extra_kwargs = {
+            "ignore": ignore,
+            "replace": replace,
+            "truncate": truncate,
+            "analyze": analyze,
+        }
+        if not_null:
+            extra_kwargs["not_null"] = set(not_null)
+        if default:
+            extra_kwargs["defaults"] = dict(default)
+        if upsert:
+            extra_kwargs["upsert"] = upsert
+
+        # docs should all be dictionaries
+        docs = (verify_is_dict(doc) for doc in docs)
+
+        # Apply {"$base64": true, ...} decoding, if needed
+        docs = (decode_base64_values(doc) for doc in docs)
+
+        # For bulk_sql= we use cursor.executemany() instead
+        if bulk_sql:
+            if batch_size:
+                doc_chunks = chunks(docs, batch_size)
+            else:
+                doc_chunks = [docs]
+            for doc_chunk in doc_chunks:
+                with db.conn:
+                    db.conn.cursor().executemany(bulk_sql, doc_chunk)
+            return
 
-    try:
-        db[table].insert_all(
-            docs, pk=pk, batch_size=batch_size, alter=alter, **extra_kwargs
-        )
-    except Exception as e:
-        if (
-            isinstance(e, OperationalError)
-            and e.args
-            and "has no column named" in e.args[0]
-        ):
-            raise click.ClickException(
-                "{}\n\nTry using --alter to add additional columns".format(e.args[0])
+        try:
+            db[table].insert_all(
+                docs, pk=pk, batch_size=batch_size, alter=alter, **extra_kwargs
             )
-        # If we can find sql= and parameters= arguments, show those
-        variables = _find_variables(e.__traceback__, ["sql", "parameters"])
-        if "sql" in variables and "parameters" in variables:
-            raise click.ClickException(
-                "{}\n\nsql = {}\nparameters = {}".format(
-                    str(e), variables["sql"], variables["parameters"]
+        except Exception as e:
+            if (
+                isinstance(e, OperationalError)
+                and e.args
+                and "has no column named" in e.args[0]
+            ):
+                raise click.ClickException(
+                    "{}\n\nTry using --alter to add additional columns".format(
+                        e.args[0]
+                    )
                 )
-            )
-        else:
-            raise
-    if tracker is not None:
-        db[table].transform(types=tracker.types)
-
-    # Clean up open file-like objects
-    if sniff_buffer:
-        sniff_buffer.close()
-    if decoded_buffer:
-        decoded_buffer.close()
+            # If we can find sql= and parameters= arguments, show those
+            variables = _find_variables(e.__traceback__, ["sql", "parameters"])
+            if "sql" in variables and "parameters" in variables:
+                raise click.ClickException(
+                    "{}\n\nsql = {}\nparameters = {}".format(
+                        str(e), variables["sql"], variables["parameters"]
+                    )
+                )
+            else:
+                raise
+        if tracker is not None:
+            db[table].transform(types=tracker.types)
+
+        # Clean up open file-like objects
+        if sniff_buffer:
+            sniff_buffer.close()
+        if decoded_buffer:
+            decoded_buffer.close()
 
 
 def _find_variables(tb, vars):