golang.org/x/build v0.0.0-20190111050920-041ab4dc3f9d

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify pkg:golang/golang.org/x/build@v0.0.0-20190111050920-041ab4dc3f9d
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/build@v0.0.0-20190111050920-041ab4dc3f9d

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:2c8237f486b76e93a47b46cf2a940900bd7c96947c5cfd53904aa594cc84fac9","contract":["envutil.Dedup removes duplicate environment variables keeping the last occurrence","envutil.Dedup caseInsensitive normalizes keys ignoring letter case","envutil.Dedup retains entries lacking an equals separator","tarutil.FileList TarGz generates valid gzip tar archive with added files","types.ReverseBuilderStatus Host returns ReverseHostStatus for specified host type"],"goal":"verify pkg:golang/golang.org/x/build@v0.0.0-20190111050920-041ab4dc3f9d","kind":"HOW","packages":["pkg:golang/golang.org/x/build@v0.0.0-20190111050920-041ab4dc3f9d"],"schemaVersion":1},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/golang.org/x/build@v0.0.0-20190111050920-041ab4dc3f9d"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/build@v0.0.0-20190111050920-041ab4dc3f9d","verifierAdapter":"golang@1"}

module sample

go 1.26.6

require golang.org/x/build v0.0.0-20190111050920-041ab4dc3f9d

cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
cloud.google.com/go v0.31.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
dmitri.shuralyov.com/app/changes v0.0.0-20180602232624-0a106ad413e3/go.mod h1:Yl+fi1br7+Rr3LqpNJf1/uxUdtRUV+Tnj0o93V2B9MU=
dmitri.shuralyov.com/html/belt v0.0.0-20180602232347-f7d459c86be0/go.mod h1:JLBrvjyP0v+ecvNYvCpyZgu5/xkfAUhi6wJj28eUfSU=
dmitri.shuralyov.com/service/change v0.0.0-20181023043359-a85b471d5412/go.mod h1:a1inKt/atXimZ4Mv927x+r7UpyzRUf4emIoiiSC2TN4=
dmitri.shuralyov.com/state v0.0.0-20180228185332-28bcc343414c/go.mod h1:0PRwlb0D6DFvNNtx+9ybjezNCa8XF0xaYcETyp6rHWU=
git.apache.org/thrift.git v0.0.0-20180902110319-2566ecd5d999/go.mod h1:fPE2ZNJGynbRyZ4dJvy6G277gSllfV2HJqblrnkyeyg=
github.com/anmitsu/go-shlex v0.0.0-20161002113705-648efa622239/go.mod h1:2FmKhYUyUczH0OGQWaF5ceTx0UBShxjsH6f8oGKYe2c=
github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
github.com/bradfitz/go-smtpd v0.0.0-20170404230938-deb6d6237625/go.mod h1:HYsPBTaaSFSlLx/70C2HPIMNZpVV8+vt/A+FMnYP11g=
github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
github.com/coreos/go-systemd v0.0.0-20181012123002-c6f51f82210d/go.mod h1:F5haX7vjVVG0kc13fIWeqUViNPyEJxv/OmvnBo0Yme4=
github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/dustin/go-humanize v1.0.0/go.mod h1:HtrtbFcZ19U5GC7JDqmcUSB87Iq5E25KnS6fMYU6eOk=
github.com/flynn/go-shlex v0.0.0-20150515145356-3f9db97f8568/go.mod h1:xEzjJPgXI435gkrCt3MPfRiAkVrwSbHsst4LCFVfpJc=
github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
github.com/ghodss/yaml v1.0.0/go.mod h1:4dBDuWmgqj2HViK6kFavaiC9ZROes6MMH2rRYeMEF04=
github.com/gliderlabs/ssh v0.1.1/go.mod h1:U7qILu1NlMHj9FlMhZLlkCdDnU1DBEAqr0aevW3Awn0=
github.com/gogo/protobuf v1.1.1/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=
github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b/go.mod h1:SBH7ygxi8pfUlaOkMMuAQtPIUF8ecWP5IEl/CR7VP2Q=
github.com/golang/lint v0.0.0-20180702182130-06c8688daad7/go.mod h1:tluoj9z5200jBnyusfRPU2LqT6J+DAorxEvtC7LHB+E=
github.com/golang/mock v1.1.1/go.mod h1:oTYuIxOrZwtPieC+H1uAHpcLFnEyAGVDL/k47Jfbm0A=
github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
github.com/google/go-cmp v0.2.0/go.mod h1:oXzfMopK8JAjlY9xF4vHSVASa0yLyX7SntLO5aqRK0M=
github.com/google/go-github v17.0.0+incompatible/go.mod h1:zLgOLi98H3fifZn+44m+umXrS52loVEgC2AApnigrVQ=
github.com/google/go-querystring v1.0.0/go.mod h1:odCYkC5MyYFN7vkCjXpyrEuKhc/BUO6wN/zVPAxq5ck=
github.com/google/martian v2.1.0+incompatible/go.mod h1:9I4somxYTbIHy5NJKHRl3wXiIaQGbYVAs8BPL6v8lEs=
github.com/googleapis/gax-go v2.0.0+incompatible/go.mod h1:SFVmujtThgffbyetf+mdk2eWhX2bMyUtNHzFKcPA9HY=
github.com/gopherjs/gopherjs v0.0.0-20181017120253-0766667cb4d1/go.mod h1:wJfORRmW1u3UXTncJ5qlYoELFm8eSnnEO6hX4iZ3EWY=
github.com/gregjones/httpcache v0.0.0-20180305231024-9cad4c3443a7/go.mod h1:FecbI9+v66THATjSRHfNgh1IVFe/9kFxbXtjV0ctIMA=
github.com/grpc-ecosystem/grpc-gateway v1.5.0/go.mod h1:RSKVYQBd5MCa4OVpNdGskqpgL2+G+NZTnrVHpWWfpdw=
github.com/jellevandenhooff/dkim v0.0.0-20150330215556-f50fe3d243e1/go.mod h1:E0B/fFc00Y+Rasa88328GlI/XbtyysCtTHZS8h7IrBU=
github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
github.com/kr/pty v1.1.3/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
github.com/matttproud/golang_protobuf_extensions v1.0.1/go.mod h1:D8He9yQNgCq6Z5Ld7szi9bcBfOoFv/3dc6xSMkL2PC0=
github.com/microcosm-cc/bluemonday v1.0.1/go.mod h1:hsXNsILzKxV+sX77C5b8FSuKF00vh2OMYv+xgHpAMF4=
github.com/neelance/astrewrite v0.0.0-20160511093645-99348263ae86/go.mod h1:kHJEU3ofeGjhHklVoIGuVj85JJwZ6kWPaJwCIxgnFmo=
github.com/neelance/sourcemap v0.0.0-20151028013722-8c68805598ab/go.mod h1:Qr6/a/Q4r9LP1IltGz7tA7iOK1WonHEYhu1HRBA7ZiM=
github.com/openzipkin/zipkin-go v0.1.1/go.mod h1:NtoC/o8u3JlF1lSlyPNswIbeQH9bJTmOf0Erfk+hxe8=
github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/prometheus/client_golang v0.8.0/go.mod h1:7SWBe2y4D6OKWSNQJUaRYU/AaXPKyh/dDVn+NZz0KFw=
github.com/prometheus/client_model v0.0.0-20180712105110-5c3871d89910/go.mod h1:MbSGuTsp3dbXC40dX6PRTWyKYBIrTGTE9sqQNg2J8bo=
github.com/prometheus/common v0.0.0-20180801064454-c7de2306084e/go.mod h1:daVV7qP5qjZbuso7PdcryaAu0sAZbrN9i7WWcTMWvro=
github.com/prometheus/procfs v0.0.0-20180725123919-05ee40e3a273/go.mod h1:c3At6R/oaqEKCNdg8wHV1ftS6bRYblBhIjjI8uT2IGk=
github.com/russross/blackfriday v1.5.2/go.mod h1:JO/DiYxRf+HjHt06OyowR9PTA263kcR/rfWxYHBV53g=
github.com/sergi/go-diff v1.0.0/go.mod h1:0CfEIISq7TuYL3j771MWULgwwjU+GofnZX9QAmXWZgo=
github.com/shurcooL/component v0.0.0-20170202220835-f88ec8f54cc4/go.mod h1:XhFIlyj5a1fBNx5aJTbKoIq0mNaPvOagO+HjB3EtxrY=
github.com/shurcooL/events v0.0.0-20181021180414-410e4ca65f48/go.mod h1:5u70Mqkb5O5cxEA8nxTsgrgLehJeAw6Oc4Ab1c/P1HM=
github.com/shurcooL/github_flavored_markdown v0.0.0-20181002035957-2122de532470/go.mod h1:2dOwnU2uBioM+SGy2aZoq1f/Sd1l9OkAeAUvjSyvgU0=
github.com/shurcooL/go v0.0.0-20180423040247-9e1955d9fb6e/go.mod h1:TDJrrUr11Vxrven61rcy3hJMUqaf/CLWYhHNPmT14Lk=
github.com/shurcooL/go-goon v0.0.0-20170922171312-37c2f522c041/go.mod h1:N5mDOmsrJOB+vfqUK+7DmDyjhSLIIBnXo9lvZJj3MWQ=
github.com/shurcooL/gofontwoff v0.0.0-20180329035133-29b52fc0a18d/go.mod h1:05UtEgK5zq39gLST6uB0cf3NEHjETfB4Fgr3Gx5R9Vw=
github.com/shurcooL/gopherjslib v0.0.0-20160914041154-feb6d3990c2c/go.mod h1:8d3azKNyqcHP1GaQE/c6dDgjkgSx2BZ4IoEi4F1reUI=
github.com/shurcooL/highlight_diff v0.0.0-20170515013008-09bb4053de1b/go.mod h1:ZpfEhSmds4ytuByIcDnOLkTHGUI6KNqRNPDLHDk+mUU=
github.com/shurcooL/highlight_go v0.0.0-20181028180052-98c3abbbae20/go.mod h1:UDKB5a1T23gOMUJrI+uSuH0VRDStOiUVSjBTRDVBVag=
github.com/shurcooL/home v0.0.0-20181020052607-80b7ffcb30f9/go.mod h1:+rgNQw2P9ARFAs37qieuu7ohDNQ3gds9msbT2yn85sg=
github.com/shurcooL/htmlg v0.0.0-20170918183704-d01228ac9e50/go.mod h1:zPn1wHpTIePGnXSHpsVPWEktKXHr6+SS6x/IKRb7cpw=
github.com/shurcooL/httperror v0.0.0-20170206035902-86b7830d14cc/go.mod h1:aYMfkZ6DWSJPJ6c4Wwz3QtW22G7mf/PEgaB9k/ik5+Y=
github.com/shurcooL/httpfs v0.0.0-20171119174359-809beceb2371/go.mod h1:ZY1cvUeJuFPAdZ/B6v7RHavJWZn2YPVFQ1OSXhCGOkg=
github.com/shurcooL/httpgzip v0.0.0-20180522190206-b1c53ac65af9/go.mod h1:919LwcH0M7/W4fcZ0/jy0qGght1GIhqyS/EgWGH2j5Q=
github.com/shurcooL/issues v0.0.0-20181008053335-6292fdc1e191/go.mod h1:e2qWDig5bLteJ4fwvDAc2NHzqFEthkqn7aOZAOpj+PQ=
github.com/shurcooL/issuesapp v0.0.0-20180602232740-048589ce2241/go.mod h1:NPpHK2TI7iSaM0buivtFUc9offApnI0Alt/K8hcHy0I=
github.com/shurcooL/notifications v0.0.0-20181007000457-627ab5aea122/go.mod h1:b5uSkrEVM1jQUspwbixRBhaIjIzL2xazXp6kntxYle0=
github.com/shurcooL/octicon v0.0.0-20181028054416-fa4f57f9efb2/go.mod h1:eWdoE5JD4R5UVWDucdOPg1g2fqQRq78IQa9zlOV1vpQ=
github.com/shurcooL/reactions v0.0.0-20181006231557-f2e0b4ca5b82/go.mod h1:TCR1lToEk4d2s07G3XGfz2QrgHXg4RJBvjrOozvoWfk=
github.com/shurcooL/sanitized_anchor_name v0.0.0-20170918181015-86672fcb3f95/go.mod h1:1NzhyTcUVG4SuEtjjoZeVRXNmyL/1OwPU0+IJeTBvfc=
github.com/shurcooL/users v0.0.0-20180125191416-49c67e49c537/go.mod h1:QJTqeLYEDaXHZDBsXlPCDqdhQuJkuw4NOtaxYe3xii4=
github.com/shurcooL/webdavfs v0.0.0-20170829043945-18c3829fa133/go.mod h1:hKmq5kWdCj2z2KEozexVbfEZIWiTjhE0+UjmZgPqehw=
github.com/sourcegraph/annotate v0.0.0-20160123013949-f4cad6c6324d/go.mod h1:UdhH50NIW0fCiwBSr0co2m7BnFLdv4fQTgdqdJTHFeE=
github.com/sourcegraph/syntaxhighlight v0.0.0-20170531221838-bd320f5d308e/go.mod h1:HuIsMU8RRBOtsCgI77wP899iHVBQpCmg4ErYMZB+2IA=
github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
github.com/tarm/serial v0.0.0-20180830185346-98f6abe2eb07/go.mod h1:kDXzergiv9cbyO7IOYJZWg1U88JhDg3PB6klq9Hg2pA=
go.opencensus.io v0.18.0/go.mod h1:vKdFvxhtzZ9onBp9VKHK8z/sRpBMnKAsufL7wlDrCOA=
go4.org v0.0.0-20180809161055-417644f6feb5/go.mod h1:MkTOUMDaeVYJUOUsaDXIhWPZYa1yOyC1qaOBpL57BhE=
golang.org/x/build v0.0.0-20190111050920-041ab4dc3f9d h1:E2M5QgjZ/Jg+ObCQAudsXxuTsLj7Nl5RV/lZcQZmKSo=
golang.org/x/build v0.0.0-20190111050920-041ab4dc3f9d/go.mod h1:OWs+y06UdEOHN4y+MfF/py+xQ/tYqIWW03b70/CG9Rw=
golang.org/x/crypto v0.0.0-20181030102418-4d3f4d9ffa16/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
golang.org/x/lint v0.0.0-20180702182130-06c8688daad7/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
golang.org/x/net v0.0.0-20180724234803-3673e40ba225/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
golang.org/x/net v0.0.0-20180826012351-8a410e7b638d/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
golang.org/x/net v0.0.0-20180906233101-161cd47e91fd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
golang.org/x/net v0.0.0-20181029044818-c44066c5c816/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
golang.org/x/oauth2 v0.0.0-20181017192945-9dcd33a902f4/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
golang.org/x/perf v0.0.0-20180704124530-6e6d33e29852/go.mod h1:JLpeXjPJfIyPr5TlbXLkXWLhP8nz10XfvxElABhCtcw=
golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
golang.org/x/sys v0.0.0-20180909124046-d0be0721c37e/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
golang.org/x/sys v0.0.0-20181029174526-d69651ed3497/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
golang.org/x/text v0.3.1-0.20180807135948-17ff2d5776d2/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
golang.org/x/time v0.0.0-20180412165947-fbb02b2291d2/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
golang.org/x/tools v0.0.0-20180828015842-6cd1fcedba52/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
golang.org/x/tools v0.0.0-20181030000716-a0a13e073c7b/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
google.golang.org/api v0.0.0-20180910000450-7ca32eb868bf/go.mod h1:4mhQ8q/RsB7i+udVvVy5NUi08OU8ZlA0gRVgrF7VFY0=
google.golang.org/api v0.0.0-20181030000543-1d582fd0359e/go.mod h1:4mhQ8q/RsB7i+udVvVy5NUi08OU8ZlA0gRVgrF7VFY0=
google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=
google.golang.org/appengine v1.2.0/go.mod h1:xpcJRLb0r/rnEns0DIKYYv+WjYCduHsrkT7/EB5XEv4=
google.golang.org/genproto v0.0.0-20180817151627-c66870c02cf8/go.mod h1:JiN7NxoALGmiZfu7CAH4rXhgtRTLTxftemlI0sWmxmc=
google.golang.org/genproto v0.0.0-20180831171423-11092d34479b/go.mod h1:JiN7NxoALGmiZfu7CAH4rXhgtRTLTxftemlI0sWmxmc=
google.golang.org/genproto v0.0.0-20181029155118-b69ba1387ce2/go.mod h1:JiN7NxoALGmiZfu7CAH4rXhgtRTLTxftemlI0sWmxmc=
google.golang.org/grpc v1.14.0/go.mod h1:yo6s7OP7yaDglbqo1J04qKzAhqBH6lvTonzMVmEdcZw=
google.golang.org/grpc v1.16.0/go.mod h1:0JHn/cJsOMiMfNA9+DeHDlAU7KAAB5GDlYFpa9MZMio=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
gopkg.in/inf.v0 v0.9.1/go.mod h1:cWUDdTG/fYaXco+Dcufb5Vnc6Gp2YChqWtbxRZE0mXw=
gopkg.in/yaml.v2 v2.2.1/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
grpc.go4.org v0.0.0-20170609214715-11d0a25b4919/go.mod h1:77eQGdRu53HpSqPFJFmuJdjuHRquDANNeA4x7B8WQ9o=
honnef.co/go/tools v0.0.0-20180728063816-88497007e858/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
sourcegraph.com/sourcegraph/go-diff v0.5.0/go.mod h1:kuch7UrkMzY0X+p9CRK03kfuPQ2zzQcaEFbx8wA8rck=
sourcegraph.com/sqs/pbtypes v0.0.0-20180604144634-d3ebe8f20ae4/go.mod h1:ketZ/q3QxT9HOBeFhu6RdvsftgpsbFHBF5Cas6cDKZ0=

package main

import (
	"archive/tar"
	"bytes"
	"fmt"
	"io"

	"golang.org/x/build/envutil"
	"golang.org/x/build/tarutil"
	"golang.org/x/build/types"
)

func main() {
	env := []string{"KEY1=val1", "KEY2=val2", "KEY1=val3"}
	deduped := envutil.Dedup(false, env)
	fmt.Printf("Deduped environment: %v\n", deduped)

	fl := &tarutil.FileList{}
	content := []byte("sample payload")
	fl.AddRegular(&tar.Header{Name: "data.txt", Mode: 0644, Size: int64(len(content))}, int64(len(content)), bytes.NewReader(content))
	rc := fl.TarGz()
	defer rc.Close()
	data, _ := io.ReadAll(rc)
	fmt.Printf("Gzip archive size: %d bytes\n", len(data))

	status := &types.ReverseBuilderStatus{}
	host := status.Host("example-host")
	fmt.Printf("Host type: %s\n", host.HostType)
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/golang.org/x/build@v0.0.0-20190111050920-041ab4dc3f9d",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/build@v0.0.0-20190111050920-041ab4dc3f9d"
  ]
}

package main

import (
	"archive/tar"
	"bytes"
	"compress/gzip"
	"fmt"
	"io"
	"os"

	"golang.org/x/build/envutil"
	"golang.org/x/build/tarutil"
	"golang.org/x/build/types"
)

func main() {
	if err := runContractTests(); err != nil {
		fmt.Fprintf(os.Stderr, "Contract test failed: %v\n", err)
		os.Exit(1)
	}
	fmt.Println("All contract assertions passed.")
}

func runContractTests() error {
	// Assertion 1: envutil.Dedup removes duplicate environment variables keeping the last occurrence
	{
		env := []string{"FOO=1", "BAR=2", "FOO=3"}
		got := envutil.Dedup(false, env)
		if len(got) != 2 || got[0] != "FOO=3" || got[1] != "BAR=2" {
			return fmt.Errorf("Assertion 1 failed: expected [FOO=3 BAR=2], got %v", got)
		}
	}

	// Assertion 2: envutil.Dedup caseInsensitive normalizes keys ignoring letter case
	{
		env := []string{"foo=1", "FOO=2"}
		got := envutil.Dedup(true, env)
		if len(got) != 1 || got[0] != "FOO=2" {
			return fmt.Errorf("Assertion 2 failed: expected [FOO=2], got %v", got)
		}
	}

	// Assertion 3: envutil.Dedup retains entries lacking an equals separator
	{
		env := []string{"NO_EQUALS", "A=1", "INVALID"}
		got := envutil.Dedup(false, env)
		if len(got) != 3 || got[0] != "NO_EQUALS" || got[1] != "A=1" || got[2] != "INVALID" {
			return fmt.Errorf("Assertion 3 failed: expected [NO_EQUALS A=1 INVALID], got %v", got)
		}
	}

	// Assertion 4: tarutil.FileList TarGz generates valid gzip tar archive with added files
	{
		fl := &tarutil.FileList{}
		fileContent := []byte("sample file content for verification")
		header := &tar.Header{
			Name: "test.txt",
			Mode: 0644,
			Size: int64(len(fileContent)),
		}
		fl.AddRegular(header, int64(len(fileContent)), bytes.NewReader(fileContent))

		rc := fl.TarGz()
		defer rc.Close()

		gr, err := gzip.NewReader(rc)
		if err != nil {
			return fmt.Errorf("Assertion 4 failed creating gzip reader: %w", err)
		}
		defer gr.Close()

		tr := tar.NewReader(gr)
		h, err := tr.Next()
		if err != nil {
			return fmt.Errorf("Assertion 4 failed reading tar header: %w", err)
		}
		if h.Name != "test.txt" || h.Size != int64(len(fileContent)) {
			return fmt.Errorf("Assertion 4 header mismatch: got name=%s size=%d", h.Name, h.Size)
		}

		readContent, err := io.ReadAll(tr)
		if err != nil {
			return fmt.Errorf("Assertion 4 failed reading tar content: %w", err)
		}
		if !bytes.Equal(readContent, fileContent) {
			return fmt.Errorf("Assertion 4 content mismatch: expected %q, got %q", fileContent, readContent)
		}
	}

	// Assertion 5: types.ReverseBuilderStatus Host returns ReverseHostStatus for specified host type
	{
		status := &types.ReverseBuilderStatus{}
		host1 := status.Host("example-host")
		if host1 == nil || host1.HostType != "example-host" {
			return fmt.Errorf("Assertion 5 failed: expected HostType example-host")
		}

		host2 := status.Host("example-host")
		if host1 != host2 {
			return fmt.Errorf("Assertion 5 failed: expected idempotent Host pointer")
		}
	}

	return nil
}