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ENH: show schemas difference when throwing InvalidSchema exception #350
ENH: show schemas difference when throwing InvalidSchema exception #350
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Thanks for the contribution! I left some feedback in the review. I'm concerned about the case where column orders don't line up.
else: | ||
diffs_left = len(schema_difference) - 3 | ||
schema_difference = schema_difference[:3] | ||
if diffs_left != 0: |
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Doesn't this always evaluate to True
? Might be throwing off our branch test-coverage numbers if so.
if len(schema_difference) < 4: | ||
diff_to_show = "\n".join(schema_difference) | ||
else: | ||
diffs_left = len(schema_difference) - 3 | ||
schema_difference = schema_difference[:3] | ||
if diffs_left != 0: | ||
schema_difference.append("And {} more left.".format(diffs_left)) | ||
diff_to_show = "\n".join(schema_difference) |
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Nit: Since the diff_to_show = "\n".join(schema_difference)
is duplicated, we can refactor this a bit.
if len(schema_difference) < 4: | |
diff_to_show = "\n".join(schema_difference) | |
else: | |
diffs_left = len(schema_difference) - 3 | |
schema_difference = schema_difference[:3] | |
if diffs_left != 0: | |
schema_difference.append("And {} more left.".format(diffs_left)) | |
diff_to_show = "\n".join(schema_difference) | |
if len(schema_difference) > 3: | |
diffs_left = len(schema_difference) - 3 | |
schema_difference = schema_difference[:3] | |
schema_difference.append("And {} more left.".format(diffs_left)) | |
diff_to_show = "\n".join(schema_difference) |
"""Calculates difference in dataframe and BigQuery schemas. | ||
|
||
Compares dataframe and BigQuery schemas to identify exact differences | ||
in each field (field can be missing in the dataframe or field can have |
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Missing fields in the dataframe should be OK, right? It's extra fields in the dataframe that can be a problem (unless we allow field addition, as requested here: #107)
for field_remote in fields_remote: | ||
for field_local in fields_local: | ||
if field_local["name"] == field_remote["name"]: | ||
if field_local["type"] != field_remote["type"]: |
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This might miss type mismatches if the order of the columns is different in either field_remote
or field_local
(or does _clean_schema_fields
sort them?). I think we'd want:
- Loop through only
fields_local
(dataframe) - Check if the field name isn't in
fields_remote
(table) - Check if the field types don't match
), | ||
( | ||
[ | ||
{"name": "A", "type": "FLOAT"}, |
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I think we'll want some tests where the order of the columns doesn't line up. That way we can be sure we aren't showing errors that aren't actually errors.
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Oops. Last review was meant to be request changes
Checking in - this PR has set for some time. Close? Revise? |
Hey, sorry, unfortunately, I do not have time to work on this one |
After merging this PR -
to_gbq
method will show a more detailed description of an error in case ofappend
mode.In particular, it will show at most 3 differences in schemas (both missing field and the same field but a different type) and will indicate how many more differences left (if any).
In #349 there was a suggestion to use
set
to compare schemas, but the elements havedict
type, so they are not hashable. So I decided to go with a more straightforward solution and compare dataframe and BigQuery fields one by one. And I am doing this only if the dataframe schema is not a subset of a BigQuery schema to leave the number of successful path operations the same.Do you want me to add more system-level tests to verify different exception messages or is it enough to have them covered by unit tests?
nox -s blacken lint
docs/source/changelog.rst
entry