Handle escape sequences in GraphQL strings

[pubmodmatt]

As defined in the GraphQL spec, standard strings may contain escape sequences, and block strings have their whitespace modified to remove any common indent or leading whitespace lines.

The Apollo Connectors feature parses various GraphQL strings in the @connect and @source directives, and provides messages with location information when there are problems within the content of those strings. To prevent each parser from having to handle escape sequences, the parsers should execute on the strings returned by apollo-compiler, which processes the escape sequences and block string whitespace. This requires mapping the locations returned by the parsers back to the corresponding locations in the original file by reversing the rules for handling escape sequences and whitespace. These changes provide that mapping.

Limitations

The following known limitations still exist:

• The GraphQL spec allows line endings to be \n, \r\n, or just a single \r character. The location mapping does not function properly with the last case. The line-col dependency used to convert offsets to line/column values only handles \n newlines, and as such, this code does not attempt to handle that case either.
• Unicode surrogate pairs cannot be used in escape sequences, due to an open issue in the apollo-rs dependency. Strings containing these sequences will not be recognized as GraphQL strings by the compiler. An example is the codepoint pair \uD83E\uDD80, which corresponds to the 🦀 character.
• Some of the parsers, such as the JSON Selection parser, do not appear to handle \b (backspace) and \f(form feed) escape sequences allowed by the GraphQL spec. Strings containing those characters will result in parse errors.

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Checklist

Complete the checklist (and note appropriate exceptions) before the PR is marked ready-for-review.

• Changes are compatible¹
• Documentation² completed
• Performance impact assessed and acceptable
• Tests added and passing³
  • Unit Tests
  • Integration Tests
  • Manual Tests

Exceptions

Note any exceptions here

Notes

Footnotes

1. It may be appropriate to bring upcoming changes to the attention of other (impacted) groups. Please endeavour to do this before seeking PR approval. The mechanism for doing this will vary considerably, so use your judgement as to how and when to do this. ↩

2. Configuration is an important part of many changes. Where applicable please try to document configuration examples. ↩

3. Tick whichever testing boxes are applicable. If you are adding Manual Tests, please document the manual testing (extensively) in the Exceptions. ↩

[svc-apollo-docs]

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[router-perf]

CI performance tests

• connectors-const - Connectors stress test that runs with a constant number of users
• const - Basic stress test that runs with a constant number of users
• demand-control-instrumented - A copy of the step test, but with demand control monitoring and metrics enabled
• demand-control-uninstrumented - A copy of the step test, but with demand control monitoring enabled
• enhanced-signature - Enhanced signature enabled
• events - Stress test for events with a lot of users and deduplication ENABLED
• events_big_cap_high_rate - Stress test for events with a lot of users, deduplication enabled and high rate event with a big queue capacity
• events_big_cap_high_rate_callback - Stress test for events with a lot of users, deduplication enabled and high rate event with a big queue capacity using callback mode
• events_callback - Stress test for events with a lot of users and deduplication ENABLED in callback mode
• events_without_dedup - Stress test for events with a lot of users and deduplication DISABLED
• events_without_dedup_callback - Stress test for events with a lot of users and deduplication DISABLED using callback mode
• extended-reference-mode - Extended reference mode enabled
• large-request - Stress test with a 1 MB request payload
• no-tracing - Basic stress test, no tracing
• reload - Reload test over a long period of time at a constant rate of users
• step-jemalloc-tuning - Clone of the basic stress test for jemalloc tuning
• step-local-metrics - Field stats that are generated from the router rather than FTV1
• step-with-prometheus - A copy of the step test with the Prometheus metrics exporter enabled
• step - Basic stress test that steps up the number of users over time
• xlarge-request - Stress test with 10 MB request payload
• xxlarge-request - Stress test with 100 MB request payload

[lennyburdette]

this is awesome, you should show this to the apollo-rs folks!