Add `io::ErrorKind::TooManyOpenFiles` by valentynkit · Pull Request #158326 · rust-lang/rust

valentynkit · 2026-06-23T19:07:51Z

Adds an unstable io::ErrorKind::TooManyOpenFiles for the open-file-limit condition.

EMFILE and ENFILE currently decode to ErrorKind::Uncategorized, so stable code cannot tell that an operation failed because the process or the system ran out of file descriptors without inspecting raw_os_error() and a platform-specific libc/windows-sys constant.

Implements the accepted ACP rust-lang/libs-team#818, including its decision to collapse EMFILE and ENFILE into a single variant. Finer-grained handling stays available through raw_os_error().

The variant maps:

EMFILE / ENFILE on Unix and WASI
ERROR_TOO_MANY_OPEN_FILES / WSAEMFILE on Windows
FR_TOO_MANY_OPEN_FILES on VEXos

Tracking issue: #158319

r? libs

`EMFILE` and `ENFILE` decoded to `ErrorKind::Uncategorized`, so running out of file descriptors could only be detected through `raw_os_error()`. Map them, and the equivalent codes on Windows (`ERROR_TOO_MANY_OPEN_FILES`, `WSAEMFILE`) and VEXos (`FR_TOO_MANY_OPEN_FILES`), to a new unstable `TooManyOpenFiles` variant.

rust-log-analyzer · 2026-06-23T19:10:49Z

A job failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

  IMAGE: x86_64-gnu-tools
##[endgroup]
    Updating crates.io index
error: failed to get `adler2` as a dependency of package `miniz_oxide v0.8.8`
    ... which satisfies dependency `miniz_oxide = "^0.8.5"` of package `flate2 v1.1.9`
    ... which satisfies dependency `flate2 = "^1.1.9"` of package `citool v0.1.0 (/home/runner/work/rust/rust/src/ci/citool)`

Caused by:
  failed to load source for dependency `adler2`

Caused by:
  unable to update registry `crates-io`

Caused by:
  download of ad/le/adler2 failed

Caused by:
  curl failed

Caused by:

jhpratt · 2026-06-24T03:47:21Z

@bors r+ rollup

PR CI failure is spurious

rust-bors · 2026-06-24T03:47:24Z

📌 Commit 9261852 has been approved by jhpratt

It is now in the queue for this repository.

🌲 The tree is currently closed for pull requests below priority 5. This pull request will be tested once the tree is reopened.

Rollup of 35 pull requests Successful merges: - #158315 (`rust-analyzer` subtree update) - #158336 (Stop excluding `stdarch` test crates from `rust-src`) - #155739 (Add temporary scope to assert_eq and assert_ne) - #156885 (Fix misattributed type inference error span for index expressions) - #157271 (simplify some `proc_macro` things) - #157419 (move rustc_type_ir Term things to term_kind.rs) - #157883 (Remove strict invariant node_type on hir_type during ty privacy visit) - #157921 (trait solver: Resolve region vars in max universe) - #157960 (delegation: add support for infers in generics) - #157983 (Lift the same-signature restriction for `extern "tail"`) - #158053 (Optimize network address parser) - #158105 (Extract all instance shim variants into new `ShimKind` enum) - #158207 (Resolver: local/external split of `resolve_ident_in_module_non_globs_unadjusted` ) - #158279 (Follow goto and drop when linting unreachable code) - #157527 (Move derive tests into their dedicated folder) - #157807 (don't ice on non-lifetime binders under `-Zassumptions-on-binders`) - #157939 (Reorganize `tests/ui/issues` [8/N]) - #157946 (Make `char::is_private_use` and `char::is_assigned` unstably public) - #158003 (Reorganize `tests/ui/issues` [9/N]) - #158020 (Update mingw-w64 C toolchain) - #158039 (c-variadic: test that we use equality up to free lifetimes) - #158060 (Reorganize `tests/ui/issues` [10/N]) - #158222 (format: ignore println newline in foreign format hints) - #158223 (Move target checking for #[lang] to the attribute parser) - #158252 (Use `cfg_select` in `std::os`) - #158263 (Only load the feature list once in the entire resolver) - #158267 (FromUtf8Error::into_utf8_lossy better example and suggest use) - #158272 (Reorganize `tests/ui/issues` [13/N]) - #158274 (triagebot: Stop pinging myself) - #158282 (slice_split_once: bounds check optimization note) - #158300 (Improve unknown crate_type diagnostic suggestions) - #158304 (mailmap: update mu001999) - #158309 (Update `rustc-literal-escaper` version to `0.0.8`) - #158314 (Fix incorrect unsafe debug assertion in unchecked_div_exact) - #158326 (Add `io::ErrorKind::TooManyOpenFiles`)

…-files, r=jhpratt Add `io::ErrorKind::TooManyOpenFiles` Adds an unstable `io::ErrorKind::TooManyOpenFiles` for the open-file-limit condition. `EMFILE` and `ENFILE` currently decode to `ErrorKind::Uncategorized`, so stable code cannot tell that an operation failed because the process or the system ran out of file descriptors without inspecting `raw_os_error()` and a platform-specific `libc`/`windows-sys` constant. Implements the accepted ACP rust-lang/libs-team#818, including its decision to collapse `EMFILE` and `ENFILE` into a single variant. Finer-grained handling stays available through `raw_os_error()`. The variant maps: - `EMFILE` / `ENFILE` on Unix and WASI - `ERROR_TOO_MANY_OPEN_FILES` / `WSAEMFILE` on Windows - `FR_TOO_MANY_OPEN_FILES` on VEXos Tracking issue: rust-lang#158319 r? libs

Rollup of 35 pull requests Successful merges: - #158315 (`rust-analyzer` subtree update) - #158336 (Stop excluding `stdarch` test crates from `rust-src`) - #155739 (Add temporary scope to assert_eq and assert_ne) - #156885 (Fix misattributed type inference error span for index expressions) - #157271 (simplify some `proc_macro` things) - #157419 (move rustc_type_ir Term things to term_kind.rs) - #157883 (Remove strict invariant node_type on hir_type during ty privacy visit) - #157921 (trait solver: Resolve region vars in max universe) - #157960 (delegation: add support for infers in generics) - #157983 (Lift the same-signature restriction for `extern "tail"`) - #158053 (Optimize network address parser) - #158105 (Extract all instance shim variants into new `ShimKind` enum) - #158207 (Resolver: local/external split of `resolve_ident_in_module_non_globs_unadjusted` ) - #158279 (Follow goto and drop when linting unreachable code) - #157527 (Move derive tests into their dedicated folder) - #157807 (don't ice on non-lifetime binders under `-Zassumptions-on-binders`) - #157939 (Reorganize `tests/ui/issues` [8/N]) - #157946 (Make `char::is_private_use` and `char::is_assigned` unstably public) - #158003 (Reorganize `tests/ui/issues` [9/N]) - #158020 (Update mingw-w64 C toolchain) - #158039 (c-variadic: test that we use equality up to free lifetimes) - #158060 (Reorganize `tests/ui/issues` [10/N]) - #158222 (format: ignore println newline in foreign format hints) - #158223 (Move target checking for #[lang] to the attribute parser) - #158252 (Use `cfg_select` in `std::os`) - #158263 (Only load the feature list once in the entire resolver) - #158267 (FromUtf8Error::into_utf8_lossy better example and suggest use) - #158272 (Reorganize `tests/ui/issues` [13/N]) - #158274 (triagebot: Stop pinging myself) - #158282 (slice_split_once: bounds check optimization note) - #158300 (Improve unknown crate_type diagnostic suggestions) - #158304 (mailmap: update mu001999) - #158309 (Update `rustc-literal-escaper` version to `0.0.8`) - #158314 (Fix incorrect unsafe debug assertion in unchecked_div_exact) - #158326 (Add `io::ErrorKind::TooManyOpenFiles`)

Rollup merge of #158326 - valentynkit:io-error-too-many-open-files, r=jhpratt Add `io::ErrorKind::TooManyOpenFiles` Adds an unstable `io::ErrorKind::TooManyOpenFiles` for the open-file-limit condition. `EMFILE` and `ENFILE` currently decode to `ErrorKind::Uncategorized`, so stable code cannot tell that an operation failed because the process or the system ran out of file descriptors without inspecting `raw_os_error()` and a platform-specific `libc`/`windows-sys` constant. Implements the accepted ACP rust-lang/libs-team#818, including its decision to collapse `EMFILE` and `ENFILE` into a single variant. Finer-grained handling stays available through `raw_os_error()`. The variant maps: - `EMFILE` / `ENFILE` on Unix and WASI - `ERROR_TOO_MANY_OPEN_FILES` / `WSAEMFILE` on Windows - `FR_TOO_MANY_OPEN_FILES` on VEXos Tracking issue: #158319 r? libs

JonathanBrouwer · 2026-06-25T10:57:39Z

@rust-timer build 125395d
Perf run for #158342

rust-timer · 2026-06-25T22:08:01Z

Finished benchmarking commit (125395d): comparison URL.

Overall result: ❌✅ regressions and improvements - no action needed

Benchmarking means the PR may be perf-sensitive. Consider adding rollup=never if this change is not fit for rolling up.

@rustbot label: -S-waiting-on-perf -perf-regression

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	1.0%	[0.8%, 1.2%]	6
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.2%	[-0.2%, -0.2%]	1
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (primary 4.9%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	4.9%	[3.9%, 5.8%]	2
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	4.9%	[3.9%, 5.8%]	2

Cycles

Results (primary 1.6%, secondary 2.4%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	1.6%	[1.6%, 1.6%]	1
Regressions ❌ (secondary)	2.4%	[2.4%, 2.4%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	1.6%	[1.6%, 1.6%]	1

Binary size

Results (secondary 0.1%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	0.1%	[0.1%, 0.1%]	3
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Bootstrap: 503.101s -> 505.347s (0.45%)
Artifact size: 353.51 MiB -> 353.43 MiB (-0.02%)

Rollup of 35 pull requests Successful merges: - rust-lang/rust#158315 (`rust-analyzer` subtree update) - rust-lang/rust#158336 (Stop excluding `stdarch` test crates from `rust-src`) - rust-lang/rust#155739 (Add temporary scope to assert_eq and assert_ne) - rust-lang/rust#156885 (Fix misattributed type inference error span for index expressions) - rust-lang/rust#157271 (simplify some `proc_macro` things) - rust-lang/rust#157419 (move rustc_type_ir Term things to term_kind.rs) - rust-lang/rust#157883 (Remove strict invariant node_type on hir_type during ty privacy visit) - rust-lang/rust#157921 (trait solver: Resolve region vars in max universe) - rust-lang/rust#157960 (delegation: add support for infers in generics) - rust-lang/rust#157983 (Lift the same-signature restriction for `extern "tail"`) - rust-lang/rust#158053 (Optimize network address parser) - rust-lang/rust#158105 (Extract all instance shim variants into new `ShimKind` enum) - rust-lang/rust#158207 (Resolver: local/external split of `resolve_ident_in_module_non_globs_unadjusted` ) - rust-lang/rust#158279 (Follow goto and drop when linting unreachable code) - rust-lang/rust#157527 (Move derive tests into their dedicated folder) - rust-lang/rust#157807 (don't ice on non-lifetime binders under `-Zassumptions-on-binders`) - rust-lang/rust#157939 (Reorganize `tests/ui/issues` [8/N]) - rust-lang/rust#157946 (Make `char::is_private_use` and `char::is_assigned` unstably public) - rust-lang/rust#158003 (Reorganize `tests/ui/issues` [9/N]) - rust-lang/rust#158020 (Update mingw-w64 C toolchain) - rust-lang/rust#158039 (c-variadic: test that we use equality up to free lifetimes) - rust-lang/rust#158060 (Reorganize `tests/ui/issues` [10/N]) - rust-lang/rust#158222 (format: ignore println newline in foreign format hints) - rust-lang/rust#158223 (Move target checking for #[lang] to the attribute parser) - rust-lang/rust#158252 (Use `cfg_select` in `std::os`) - rust-lang/rust#158263 (Only load the feature list once in the entire resolver) - rust-lang/rust#158267 (FromUtf8Error::into_utf8_lossy better example and suggest use) - rust-lang/rust#158272 (Reorganize `tests/ui/issues` [13/N]) - rust-lang/rust#158274 (triagebot: Stop pinging myself) - rust-lang/rust#158282 (slice_split_once: bounds check optimization note) - rust-lang/rust#158300 (Improve unknown crate_type diagnostic suggestions) - rust-lang/rust#158304 (mailmap: update mu001999) - rust-lang/rust#158309 (Update `rustc-literal-escaper` version to `0.0.8`) - rust-lang/rust#158314 (Fix incorrect unsafe debug assertion in unchecked_div_exact) - rust-lang/rust#158326 (Add `io::ErrorKind::TooManyOpenFiles`)

rustbot assigned jhpratt Jun 23, 2026

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-libs Relevant to the library team, which will review and decide on the PR/issue. labels Jun 23, 2026

rust-bors Bot added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jun 24, 2026

This was referenced Jun 24, 2026

Tracking Issue for io_error_too_many_open_files #158319

Open

Rollup of 35 pull requests #158342

Merged

JonathanBrouwer mentioned this pull request Jun 24, 2026

[CI] Rollup of 35 pull requests #158354

Draft

rust-bors Bot merged commit 81526af into rust-lang:main Jun 25, 2026
2 of 13 checks passed

rustbot added this to the 1.98.0 milestone Jun 25, 2026

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Add `io::ErrorKind::TooManyOpenFiles`#158326

Add `io::ErrorKind::TooManyOpenFiles`#158326
rust-bors[bot] merged 1 commit into
rust-lang:mainfrom
valentynkit:io-error-too-many-open-files

valentynkit commented Jun 23, 2026 •

edited by rustbot

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rust-timer commented Jun 25, 2026

Overall result: ❌✅ regressions and improvements - no action needed

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valentynkit commented Jun 23, 2026 •

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