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Support reading from CSV tables with null escape and quote characters #26619

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Merged
merged 1 commit into from
Sep 13, 2025
Merged

Support reading from CSV tables with null escape and quote characters #26619

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6 changes: 5 additions & 1 deletion lib/trino-hive-formats/src/main/java/io/trino/hive/formats/line/csv/CsvDeserializer.java
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Original file line number Diff line number Diff line change
Expand Up @@ -60,7 +60,11 @@ public CsvDeserializer(List<Column> columns, char separatorChar, char quoteChar,
checkArgument(separatorChar != '\0', "Separator cannot be the null character (ASCII 0)");
checkArgument(separatorChar != quoteChar, "Separator and quote character cannot be the same");
checkArgument(separatorChar != escapeChar, "Separator and escape character cannot be the same");
checkArgument(quoteChar != escapeChar, "Quote and escape character cannot be the same");

// Quote and escape character can be the same when both are the null character (quoting and escaping are disabled)
if (quoteChar != '\0' || escapeChar != '\0') {
checkArgument(quoteChar != escapeChar, "Quote and escape character cannot be the same");
}
this.separatorChar = separatorChar;
this.quoteChar = quoteChar;
this.escapeChar = escapeChar;
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4 changes: 4 additions & 0 deletions lib/trino-hive-formats/src/test/java/io/trino/hive/formats/line/csv/TestCsvFormat.java
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Expand Up @@ -126,6 +126,10 @@ public void testCsv()
assertTrinoHiveByteForByte(true, Arrays.asList("f**", "b*r", "b*z"), Optional.of('\t'), Optional.of('*'), Optional.of('#'));
assertTrinoHiveByteForByte(false, Arrays.asList("f**", "b*r", "b*z"), Optional.of('\t'), Optional.of('*'), Optional.of('\0'));

// If both the quote character and escape character are `\0` then quoting and escaping is simply disabled, even if this would cause output that does not round trip
assertTrinoHiveByteForByte(true, Arrays.asList("foo", "bar", "baz"), Optional.of('\t'), Optional.of('\0'), Optional.of('\0'));
assertTrinoHiveByteForByte(false, Arrays.asList("f\t\t", "\tbar\t", "baz"), Optional.of('\t'), Optional.of('\0'), Optional.of('\0'));

// These cases don't round trip, because Hive uses different default escape characters for serialization and deserialization.
// For serialization the pipe character is escaped with a quote char, but for deserialization escape character is the backslash character
assertTrinoHiveByteForByte(false, Arrays.asList("|", "a", "b"), Optional.empty(), Optional.of('|'), Optional.empty());
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