[Go][#SM4] Potentially malformed test cases

[abdullahsweesi11]

I’m facing some problems on Stage #SM4, but this can be extended to the entire ‘RDB Persistence’ extension.

The goal is to find the key-value pairs in the hashmap. I have been using the key/value length to extract the key/value. However, some keys/values in the tests don’t provide the length beforehand, making it unclear how to determine when the key/value terminates. My code works correctly for other well-formed test cases.

I don’t know if this is a problem with the tests, or an oversight in reading the instructions on my behalf.

I’ve tried re-reading the instructions repeatedly, and finding a way to extract keys/values without needing the length, but was unsuccessful.

Here are my logs: (RDB file contents are logged to stdout for debugging - apologies for the large length)

[tester::#SM4] Running tests for Stage #SM4 (RDB Persistence - Read value with expiry)
[tester::#SM4] Created RDB file with 5 key-value pairs: {"pineapple": "orange", "grape": "raspberry", "strawberry": "grape", "banana": "apple", "raspberry": "strawberry"}
[tester::#SM4] $ ./your_program.sh --dir /tmp/rdbfiles523881512 --dbfilename pineapple.rdb
[your_program] Logs from your program will appear here!
[tester::#SM4] client: $ redis-cli GET pineapple
[your_program] RDB file contents:
[your_program] 524544495330303131fa72656469732d62697473c040fa0972656469732d76657205372e322e30fe00fb0505fc009cef127e010000000970696e656170706c65066f72616e6765fc000c288ac70100000005677261706509726173706265727279fc000c288ac70100000073747261776265727279056772617065fc000c288ac7010000000662616e616e61056170706c65fc000c288ac7010000000972617370626572727973747261776265727279ffdf0d97f1ff705c07
[your_program] Problem: could not find key data
[tester::#SM4] Received: "" (no content received)
[tester::#SM4]            ^ error
[tester::#SM4] Error: Expected start of a new RESP2 value (either +, -, :, $ or *)
[tester::#SM4] Test failed (try setting 'debug: true' in your codecrafters.yml to see more details)

As can be seen, the true length of ‘strawberry’ (i.e. 0xA or 10) is not listed before the key of the 3rd pair.

Ultimately, I want to know whether there is something wrong with the test case, or I need to dig deeper.

[andy1li]

Hey @abdullahsweesi11, I can confirm that the hex string is missing the size field:

That said, I’m not entirely sure the hex string itself is valid, so I re-ran your code with debug: true.

You’ll notice that two 0a bytes are missing from the hex output.

The bug is caused by bufio.Scanner, which is designed to read text files line by line, and it automatically strips line endings (\n or 0a).

To avoid this issue, you’ll want to read raw bytes instead of strings.