Add best pratice for how to check in generated files#16405
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epage merged 1 commit intorust-lang:masterfrom Dec 16, 2025
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Add best pratice for how to check in generated files#16405epage merged 1 commit intorust-lang:masterfrom
epage merged 1 commit intorust-lang:masterfrom
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Best practice here is to have a test that checks if the generated file matches, but that wasn't documented anywhere.
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r? @weihanglo rustbot has assigned @weihanglo. Use |
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| * Sometimes, projects want to check in a generated file, and treat it as | ||
| source code. However, in this case, the file shouldn't be generated from | ||
| `build.rs`. Instead, have a test or similar which checks that the file | ||
| precisely matches the generated version *and fails if the result doesn't | ||
| match*, and run that test as part of your CI. (The test can generate a | ||
| temporary file to compare to, and if you want to update the generated file, | ||
| you can replace the checked-in file with that temporary file.) |
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non-blocking: should we point people to libraries like expect-test ad snapbox for doing this?
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I'd love to point people to snapbox and insta and expect-test, yes.
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Update cargo submodule 13 commits in e91b2baa632c0c7e84216c91ecfe107c37d887c1..3861f60f6b58f57524c0e7aab1f5c1ad83e35409 2025-12-13 16:29:21 +0000 to 2025-12-19 21:53:33 +0000 - fix(sbom): Don't set CARGO_SBOM_PATH when empty (like stable) (rust-lang/cargo#16419) - chore(ci): report-timings to upload HTML report (rust-lang/cargo#16416) - fix(report): get the same feature parity of `--timings` (rust-lang/cargo#16414) - fix(docs): Document the only possible values for DEBUG in build scripts (rust-lang/cargo#16413) - fix(log): emit fingeprint log also for no-rebuild unit (rust-lang/cargo#16408) - Fix link to `doc_cfg` docs in cargo book (rust-lang/cargo#16404) - Add best pratice for how to check in generated files (rust-lang/cargo#16405) - test: Use a larger default term width (rust-lang/cargo#16403) - Document more services and permissions of the cargo team (rust-lang/cargo#16402) - fix(new): Improve quality of package name error messages (rust-lang/cargo#16398) - feat(log): add more log events (rust-lang/cargo#16390) - chore: bump to 0.95.0; update changelog (rust-lang/cargo#16395) - Cache submodule into git db (rust-lang/cargo#16246) r? ghost
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Update cargo submodule 13 commits in e91b2baa632c0c7e84216c91ecfe107c37d887c1..3861f60f6b58f57524c0e7aab1f5c1ad83e35409 2025-12-13 16:29:21 +0000 to 2025-12-19 21:53:33 +0000 - fix(sbom): Don't set CARGO_SBOM_PATH when empty (like stable) (rust-lang/cargo#16419) - chore(ci): report-timings to upload HTML report (rust-lang/cargo#16416) - fix(report): get the same feature parity of `--timings` (rust-lang/cargo#16414) - fix(docs): Document the only possible values for DEBUG in build scripts (rust-lang/cargo#16413) - fix(log): emit fingeprint log also for no-rebuild unit (rust-lang/cargo#16408) - Fix link to `doc_cfg` docs in cargo book (rust-lang/cargo#16404) - Add best pratice for how to check in generated files (rust-lang/cargo#16405) - test: Use a larger default term width (rust-lang/cargo#16403) - Document more services and permissions of the cargo team (rust-lang/cargo#16402) - fix(new): Improve quality of package name error messages (rust-lang/cargo#16398) - feat(log): add more log events (rust-lang/cargo#16390) - chore: bump to 0.95.0; update changelog (rust-lang/cargo#16395) - Cache submodule into git db (rust-lang/cargo#16246) r? ghost
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Update cargo submodule 17 commits in e91b2baa632c0c7e84216c91ecfe107c37d887c1..94c368ad2b9db0f0da5bdd8421cea13786ce4412 2025-12-13 16:29:21 +0000 to 2025-12-26 19:39:15 +0000 - fix(vendor): unpack from local-registry cache path (rust-lang/cargo#16435) - feat(index): Stabilize pubtime (rust-lang/cargo#16372) - Experiment: Render timing pipeline in SVG (rust-lang/cargo#15091) - chore(triagebot): auto-label `Command-report` (rust-lang/cargo#16429) - fix(sbom): Don't set CARGO_SBOM_PATH when empty (like stable) (rust-lang/cargo#16419) - chore(ci): report-timings to upload HTML report (rust-lang/cargo#16416) - fix(report): get the same feature parity of `--timings` (rust-lang/cargo#16414) - fix(docs): Document the only possible values for DEBUG in build scripts (rust-lang/cargo#16413) - fix(log): emit fingeprint log also for no-rebuild unit (rust-lang/cargo#16408) - Fix link to `doc_cfg` docs in cargo book (rust-lang/cargo#16404) - Add best pratice for how to check in generated files (rust-lang/cargo#16405) - test: Use a larger default term width (rust-lang/cargo#16403) - Document more services and permissions of the cargo team (rust-lang/cargo#16402) - fix(new): Improve quality of package name error messages (rust-lang/cargo#16398) - feat(log): add more log events (rust-lang/cargo#16390) - chore: bump to 0.95.0; update changelog (rust-lang/cargo#16395) - Cache submodule into git db (rust-lang/cargo#16246) r? ghost
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Update cargo submodule 17 commits in e91b2baa632c0c7e84216c91ecfe107c37d887c1..94c368ad2b9db0f0da5bdd8421cea13786ce4412 2025-12-13 16:29:21 +0000 to 2025-12-26 19:39:15 +0000 - fix(vendor): unpack from local-registry cache path (rust-lang/cargo#16435) - feat(index): Stabilize pubtime (rust-lang/cargo#16372) - Experiment: Render timing pipeline in SVG (rust-lang/cargo#15091) - chore(triagebot): auto-label `Command-report` (rust-lang/cargo#16429) - fix(sbom): Don't set CARGO_SBOM_PATH when empty (like stable) (rust-lang/cargo#16419) - chore(ci): report-timings to upload HTML report (rust-lang/cargo#16416) - fix(report): get the same feature parity of `--timings` (rust-lang/cargo#16414) - fix(docs): Document the only possible values for DEBUG in build scripts (rust-lang/cargo#16413) - fix(log): emit fingeprint log also for no-rebuild unit (rust-lang/cargo#16408) - Fix link to `doc_cfg` docs in cargo book (rust-lang/cargo#16404) - Add best pratice for how to check in generated files (rust-lang/cargo#16405) - test: Use a larger default term width (rust-lang/cargo#16403) - Document more services and permissions of the cargo team (rust-lang/cargo#16402) - fix(new): Improve quality of package name error messages (rust-lang/cargo#16398) - feat(log): add more log events (rust-lang/cargo#16390) - chore: bump to 0.95.0; update changelog (rust-lang/cargo#16395) - Cache submodule into git db (rust-lang/cargo#16246) r? ghost
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Update cargo submodule 17 commits in e91b2baa632c0c7e84216c91ecfe107c37d887c1..94c368ad2b9db0f0da5bdd8421cea13786ce4412 2025-12-13 16:29:21 +0000 to 2025-12-26 19:39:15 +0000 - fix(vendor): unpack from local-registry cache path (rust-lang/cargo#16435) - feat(index): Stabilize pubtime (rust-lang/cargo#16372) - Experiment: Render timing pipeline in SVG (rust-lang/cargo#15091) - chore(triagebot): auto-label `Command-report` (rust-lang/cargo#16429) - fix(sbom): Don't set CARGO_SBOM_PATH when empty (like stable) (rust-lang/cargo#16419) - chore(ci): report-timings to upload HTML report (rust-lang/cargo#16416) - fix(report): get the same feature parity of `--timings` (rust-lang/cargo#16414) - fix(docs): Document the only possible values for DEBUG in build scripts (rust-lang/cargo#16413) - fix(log): emit fingeprint log also for no-rebuild unit (rust-lang/cargo#16408) - Fix link to `doc_cfg` docs in cargo book (rust-lang/cargo#16404) - Add best pratice for how to check in generated files (rust-lang/cargo#16405) - test: Use a larger default term width (rust-lang/cargo#16403) - Document more services and permissions of the cargo team (rust-lang/cargo#16402) - fix(new): Improve quality of package name error messages (rust-lang/cargo#16398) - feat(log): add more log events (rust-lang/cargo#16390) - chore: bump to 0.95.0; update changelog (rust-lang/cargo#16395) - Cache submodule into git db (rust-lang/cargo#16246) r? ghost
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Update cargo submodule 17 commits in e91b2baa632c0c7e84216c91ecfe107c37d887c1..94c368ad2b9db0f0da5bdd8421cea13786ce4412 2025-12-13 16:29:21 +0000 to 2025-12-26 19:39:15 +0000 - fix(vendor): unpack from local-registry cache path (rust-lang/cargo#16435) - feat(index): Stabilize pubtime (rust-lang/cargo#16372) - Experiment: Render timing pipeline in SVG (rust-lang/cargo#15091) - chore(triagebot): auto-label `Command-report` (rust-lang/cargo#16429) - fix(sbom): Don't set CARGO_SBOM_PATH when empty (like stable) (rust-lang/cargo#16419) - chore(ci): report-timings to upload HTML report (rust-lang/cargo#16416) - fix(report): get the same feature parity of `--timings` (rust-lang/cargo#16414) - fix(docs): Document the only possible values for DEBUG in build scripts (rust-lang/cargo#16413) - fix(log): emit fingeprint log also for no-rebuild unit (rust-lang/cargo#16408) - Fix link to `doc_cfg` docs in cargo book (rust-lang/cargo#16404) - Add best pratice for how to check in generated files (rust-lang/cargo#16405) - test: Use a larger default term width (rust-lang/cargo#16403) - Document more services and permissions of the cargo team (rust-lang/cargo#16402) - fix(new): Improve quality of package name error messages (rust-lang/cargo#16398) - feat(log): add more log events (rust-lang/cargo#16390) - chore: bump to 0.95.0; update changelog (rust-lang/cargo#16395) - Cache submodule into git db (rust-lang/cargo#16246) r? ghost
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Update cargo submodule 13 commits in e91b2baa632c0c7e84216c91ecfe107c37d887c1..3861f60f6b58f57524c0e7aab1f5c1ad83e35409 2025-12-13 16:29:21 +0000 to 2025-12-19 21:53:33 +0000 - fix(sbom): Don't set CARGO_SBOM_PATH when empty (like stable) (rust-lang/cargo#16419) - chore(ci): report-timings to upload HTML report (rust-lang/cargo#16416) - fix(report): get the same feature parity of `--timings` (rust-lang/cargo#16414) - fix(docs): Document the only possible values for DEBUG in build scripts (rust-lang/cargo#16413) - fix(log): emit fingeprint log also for no-rebuild unit (rust-lang/cargo#16408) - Fix link to `doc_cfg` docs in cargo book (rust-lang/cargo#16404) - Add best pratice for how to check in generated files (rust-lang/cargo#16405) - test: Use a larger default term width (rust-lang/cargo#16403) - Document more services and permissions of the cargo team (rust-lang/cargo#16402) - fix(new): Improve quality of package name error messages (rust-lang/cargo#16398) - feat(log): add more log events (rust-lang/cargo#16390) - chore: bump to 0.95.0; update changelog (rust-lang/cargo#16395) - Cache submodule into git db (rust-lang/cargo#16246) r? ghost
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Update cargo submodule 17 commits in e91b2baa632c0c7e84216c91ecfe107c37d887c1..94c368ad2b9db0f0da5bdd8421cea13786ce4412 2025-12-13 16:29:21 +0000 to 2025-12-26 19:39:15 +0000 - fix(vendor): unpack from local-registry cache path (rust-lang/cargo#16435) - feat(index): Stabilize pubtime (rust-lang/cargo#16372) - Experiment: Render timing pipeline in SVG (rust-lang/cargo#15091) - chore(triagebot): auto-label `Command-report` (rust-lang/cargo#16429) - fix(sbom): Don't set CARGO_SBOM_PATH when empty (like stable) (rust-lang/cargo#16419) - chore(ci): report-timings to upload HTML report (rust-lang/cargo#16416) - fix(report): get the same feature parity of `--timings` (rust-lang/cargo#16414) - fix(docs): Document the only possible values for DEBUG in build scripts (rust-lang/cargo#16413) - fix(log): emit fingeprint log also for no-rebuild unit (rust-lang/cargo#16408) - Fix link to `doc_cfg` docs in cargo book (rust-lang/cargo#16404) - Add best pratice for how to check in generated files (rust-lang/cargo#16405) - test: Use a larger default term width (rust-lang/cargo#16403) - Document more services and permissions of the cargo team (rust-lang/cargo#16402) - fix(new): Improve quality of package name error messages (rust-lang/cargo#16398) - feat(log): add more log events (rust-lang/cargo#16390) - chore: bump to 0.95.0; update changelog (rust-lang/cargo#16395) - Cache submodule into git db (rust-lang/cargo#16246) r? ghost
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Update cargo submodule 17 commits in e91b2baa632c0c7e84216c91ecfe107c37d887c1..94c368ad2b9db0f0da5bdd8421cea13786ce4412 2025-12-13 16:29:21 +0000 to 2025-12-26 19:39:15 +0000 - fix(vendor): unpack from local-registry cache path (rust-lang/cargo#16435) - feat(index): Stabilize pubtime (rust-lang/cargo#16372) - Experiment: Render timing pipeline in SVG (rust-lang/cargo#15091) - chore(triagebot): auto-label `Command-report` (rust-lang/cargo#16429) - fix(sbom): Don't set CARGO_SBOM_PATH when empty (like stable) (rust-lang/cargo#16419) - chore(ci): report-timings to upload HTML report (rust-lang/cargo#16416) - fix(report): get the same feature parity of `--timings` (rust-lang/cargo#16414) - fix(docs): Document the only possible values for DEBUG in build scripts (rust-lang/cargo#16413) - fix(log): emit fingeprint log also for no-rebuild unit (rust-lang/cargo#16408) - Fix link to `doc_cfg` docs in cargo book (rust-lang/cargo#16404) - Add best pratice for how to check in generated files (rust-lang/cargo#16405) - test: Use a larger default term width (rust-lang/cargo#16403) - Document more services and permissions of the cargo team (rust-lang/cargo#16402) - fix(new): Improve quality of package name error messages (rust-lang/cargo#16398) - feat(log): add more log events (rust-lang/cargo#16390) - chore: bump to 0.95.0; update changelog (rust-lang/cargo#16395) - Cache submodule into git db (rust-lang/cargo#16246) r? ghost
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Update cargo submodule 17 commits in e91b2baa632c0c7e84216c91ecfe107c37d887c1..94c368ad2b9db0f0da5bdd8421cea13786ce4412 2025-12-13 16:29:21 +0000 to 2025-12-26 19:39:15 +0000 - fix(vendor): unpack from local-registry cache path (rust-lang/cargo#16435) - feat(index): Stabilize pubtime (rust-lang/cargo#16372) - Experiment: Render timing pipeline in SVG (rust-lang/cargo#15091) - chore(triagebot): auto-label `Command-report` (rust-lang/cargo#16429) - fix(sbom): Don't set CARGO_SBOM_PATH when empty (like stable) (rust-lang/cargo#16419) - chore(ci): report-timings to upload HTML report (rust-lang/cargo#16416) - fix(report): get the same feature parity of `--timings` (rust-lang/cargo#16414) - fix(docs): Document the only possible values for DEBUG in build scripts (rust-lang/cargo#16413) - fix(log): emit fingeprint log also for no-rebuild unit (rust-lang/cargo#16408) - Fix link to `doc_cfg` docs in cargo book (rust-lang/cargo#16404) - Add best pratice for how to check in generated files (rust-lang/cargo#16405) - test: Use a larger default term width (rust-lang/cargo#16403) - Document more services and permissions of the cargo team (rust-lang/cargo#16402) - fix(new): Improve quality of package name error messages (rust-lang/cargo#16398) - feat(log): add more log events (rust-lang/cargo#16390) - chore: bump to 0.95.0; update changelog (rust-lang/cargo#16395) - Cache submodule into git db (rust-lang/cargo#16246) r? ghost
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Best practice here is to have a test that checks if the generated file
matches, but that wasn't documented anywhere.