fix(langchain): do not throw when result is undefined

[sabrenner]

What does this PR do?

Fixes cases when the underlying chain (llm call, chat model call, embedding, or some other chain operation) results in the output of the chain or part of the chain being undefined. This only happens for LLMs and chat model calls, as the embedding handler returns early if the result is not an array (undefined isn't), and the chain handler first array-ifys the result, and since we normalize undefined to undefined, the tag never gets added to the span.

The fix adds optional chaining to the iteration over result.generations. Iterating over undefined does nothing, and since that is our only operation in getSpanEndTags for both LLMs and chat models, we return early.

Despite chain and embedding handlers not having this bug, I added regression tests to be safe.

Motivation

We do not want to throw from plugins.

[github-actions]

Overall package size

Self size: 8.1 MB
Deduped: 94.6 MB
No deduping: 94.94 MB

Dependency sizes

| name | version | self size | total size | |------|---------|-----------|------------| | @datadog/libdatadog | 0.2.2 | 29.27 MB | 29.27 MB | | @datadog/native-appsec | 8.3.0 | 19.37 MB | 19.38 MB | | @datadog/native-iast-taint-tracking | 3.2.0 | 13.9 MB | 13.91 MB | | @datadog/pprof | 5.4.1 | 9.76 MB | 10.13 MB | | protobufjs | 7.2.5 | 2.77 MB | 5.16 MB | | @datadog/native-iast-rewriter | 2.5.0 | 2.51 MB | 2.65 MB | | @opentelemetry/core | 1.14.0 | 872.87 kB | 1.47 MB | | @datadog/native-metrics | 3.0.1 | 1.06 MB | 1.46 MB | | @opentelemetry/api | 1.8.0 | 1.21 MB | 1.21 MB | | import-in-the-middle | 1.11.2 | 112.74 kB | 826.22 kB | | msgpack-lite | 0.1.26 | 201.16 kB | 281.59 kB | | opentracing | 0.14.7 | 194.81 kB | 194.81 kB | | lru-cache | 7.18.3 | 133.92 kB | 133.92 kB | | pprof-format | 2.1.0 | 111.69 kB | 111.69 kB | | @datadog/sketches-js | 2.1.0 | 109.9 kB | 109.9 kB | | semver | 7.6.3 | 95.82 kB | 95.82 kB | | lodash.sortby | 4.7.0 | 75.76 kB | 75.76 kB | | ignore | 5.3.1 | 51.46 kB | 51.46 kB | | int64-buffer | 0.1.10 | 49.18 kB | 49.18 kB | | shell-quote | 1.8.1 | 44.96 kB | 44.96 kB | | istanbul-lib-coverage | 3.2.0 | 29.34 kB | 29.34 kB | | rfdc | 1.3.1 | 25.21 kB | 25.21 kB | | @isaacs/ttlcache | 1.4.1 | 25.2 kB | 25.2 kB | | tlhunter-sorted-set | 0.1.0 | 24.94 kB | 24.94 kB | | limiter | 1.1.5 | 23.17 kB | 23.17 kB | | dc-polyfill | 0.1.4 | 23.1 kB | 23.1 kB | | retry | 0.13.1 | 18.85 kB | 18.85 kB | | jest-docblock | 29.7.0 | 8.99 kB | 12.76 kB | | crypto-randomuuid | 1.0.0 | 11.18 kB | 11.18 kB | | koalas | 1.0.2 | 6.47 kB | 6.47 kB | | path-to-regexp | 0.1.10 | 6.38 kB | 6.38 kB | | module-details-from-path | 1.0.3 | 4.47 kB | 4.47 kB |

_{🤖 This report was automatically generated by heaviest-objects-in-the-universe}

[pr-commenter]

Benchmarks

Benchmark execution time: 2024-11-22 15:49:14

Comparing candidate commit 8f383c5 in PR branch sabrenner/langchain-bugfix with baseline commit fcc3184 in branch master.

Found 1 performance improvements and 0 performance regressions! Performance is the same for 144 metrics, 0 unstable metrics.

scenario:plugin-graphql-with-depth-on-max-18

• 🟩 max_rss_usage [-65.166MB; -59.314MB] or [-6.703%; -6.101%]