Prefer AWS Go SDK pointer conversion functions instead of raw * dereferencing

[breathingdust]

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Description

The AWS Go SDK provides a large amount of type conversion functions for going from pointer values to underlying values and vice-versa. They automatically handle nil values by substituting the zero-value for a type (e.g. aws.StringValue(string) will convert a nil string to "").

We prefer using these functions to:

• Simplify SDK object access
• Prevent potential panics (many times, nil checking is not performed at all before * dereferencing)

There are still cases where nil checking is preferred due to behaviors we want in Terraform, however even in these cases we should prefer the AWS Go SDK conversion functions for consistency.

Flagged Code

value := *output.Value

Passing Code

value := aws.StringValue(output.Value)

References

• https://docs.aws.amazon.com/sdk-for-go/api/aws/

[bflad]

Covering semgrep rule for #16532:

  - id: prefer-aws-go-sdk-pointer-conversion-conditional
    languages: [go]
    message: Prefer AWS Go SDK pointer conversion functions for dereferencing during conditionals, e.g. aws.StringValue()
    paths:
      exclude:
        - awsproviderlint/vendor/
      include:
        - aws/
    patterns:
      - pattern-either:
        - pattern: '$LHS == *$RHS'
        - pattern: '*$LHS == $RHS'
    severity: WARNING

aws/resource_aws_lambda_function.go
severity:warning rule:prefer-aws-go-sdk-pointer-conversion-conditional: Prefer AWS Go SDK pointer conversion functions for dereferencing during conditionals, e.g. aws.StringValue()
817:    if *function.PackageType == lambda.PackageTypeZip {

Other covering rules to enable:

  - id: prefer-aws-go-sdk-pointer-conversion-assignment
    languages: [go]
    message: Prefer AWS Go SDK pointer conversion functions for dereferencing during assignment, e.g. aws.StringValue()
    paths:
      exclude:
        - aws/internal/generators/
        - aws/internal/keyvaluetags/
        - awsproviderlint/vendor/
      include:
        - aws/
    patterns:
      - pattern: '$LHS = *$RHS'
      - pattern-not: '*$LHS2 = *$RHS'
    severity: WARNING

e.g.

aws/resource_aws_vpc.go
severity:warning rule:prefer-aws-go-sdk-pointer-conversion-assignment: Prefer AWS Go SDK pointer conversion functions for dereferencing during assignment, e.g. aws.StringValue()
308:                    classiclink_enabled = *v.ClassicLinkEnabled
333:                    classiclinkdns_enabled = *v.ClassicLinkDnsSupported

aws/resource_aws_waf_sql_injection_match_set.go
severity:warning rule:prefer-aws-go-sdk-pointer-conversion-assignment: Prefer AWS Go SDK pointer conversion functions for dereferencing during assignment, e.g. aws.StringValue()
179:        m["text_transformation"] = *t.TextTransformation

aws/resource_aws_waf_web_acl.go
severity:warning rule:prefer-aws-go-sdk-pointer-conversion-assignment: Prefer AWS Go SDK pointer conversion functions for dereferencing during assignment, e.g. aws.StringValue()
239:    arn := *resp.WebACL.WebACLArn

  - id: prefer-aws-go-sdk-pointer-conversion-ResourceData-SetId
    languages: [go]
    message: Prefer AWS Go SDK pointer conversion aws.StringValue() function for dereferencing during d.SetId()
    paths:
      include:
        - aws/
    pattern: 'd.SetId(*$VALUE)'
    severity: WARNING

e.g.

aws/resource_aws_wafregional_web_acl.go
severity:warning rule:prefer-aws-go-sdk-pointer-conversion-ResourceData-SetId: Prefer AWS Go SDK pointer conversion aws.StringValue() function for dereferencing during d.SetId()
197:    d.SetId(*resp.WebACL.WebACLId)

aws/resource_aws_workspaces_ip_group.go
severity:warning rule:prefer-aws-go-sdk-pointer-conversion-ResourceData-SetId: Prefer AWS Go SDK pointer conversion aws.StringValue() function for dereferencing during d.SetId()
75: d.SetId(*resp.GroupId)