Add String::replace_first and String::replace_last

[WilliamVenner]

Convenience methods that use match_indices and replace_range to efficiently replace a substring in a string without reallocating, if capacity (and the implementation of Vec::splice) allows.

[rust-highfive]

Hey! It looks like you've submitted a new PR for the library teams!

If this PR contains changes to any rust-lang/rust public library APIs then please comment with @rustbot label +T-libs-api -T-libs to tag it appropriately. If this PR contains changes to any unstable APIs please edit the PR description to add a link to the relevant API Change Proposal or create one if you haven't already. If you're unsure where your change falls no worries, just leave it as is and the reviewer will take a look and make a decision to forward on if necessary.

Examples of T-libs-api changes:

• Stabilizing library features
• Introducing insta-stable changes such as new implementations of existing stable traits on existing stable types
• Introducing new or changing existing unstable library APIs (excluding permanently unstable features / features without a tracking issue)
• Changing public documentation in ways that create new stability guarantees
• Changing observable runtime behavior of library APIs

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @kennytm (or someone else) soon.

Please see the contribution instructions for more information.

[WilliamVenner]

String::replace_last is currently blocked by #89196 :[

For now I have manually specified the types in the test and doctest, but these should of course be omitted once the issue is resolved.

[WilliamVenner]

@rustbot label +T-libs-api -T-libs

[JohnCSimon]

@WilliamVenner
Returning to you to address build failures

FYI: when a PR is ready for review, send a message containing
@rustbot ready to switch to S-waiting-on-review so the PR is in the reviewer's backlog.

@rustbot author

[JohnCSimon]

@WilliamVenner
Ping from triage: I'm closing this due to inactivity, Please reopen when you are ready to continue with this.
Note: if you do please open the PR BEFORE you push to it, else you won't be able to reopen - this is a quirk of github.
Thanks for your contribution.

@rustbot label: +S-inactive

[WilliamVenner]

??? This is blocked by #98941 @JohnCSimon

[JohnCSimon]

@WilliamVenner sorry - my mistake, reopened.
Added blocked tag.

[bors]

☔ The latest upstream changes (presumably #93455) made this pull request unmergeable. Please resolve the merge conflicts.

[zachs18]

https://github.com/zachs18/rust/tree/string_replace_in_place_rebase
I have a branch with this PR's changes rebased onto current master that also somewhat avoids the blocking issue by hardcoding the doclink to ../../std/primitive.str.html#method.replacen instead of using intra-doc links. The effect of this is that the doclink is only broken if you build alloc's docs and not std's docs. There is precedent for this e.g. in core::hint::spin_loop which links to std::thread::yield_now

[WilliamVenner]

@zachs18 Thank you 🙂

[WilliamVenner]

@rustbot label: -S-blocked

[rust-log-analyzer]

The job x86_64-gnu-llvm-18 failed! Check out the build log: (web) (plain)

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

------
 > importing cache manifest from ghcr.io/rust-lang/rust-ci-cache:30ca74372d8b771363f68f939a58b017a592fae4f69398600dc51145997160f03e9652051f957840c41898984a88855e9757fa23464703a5a4ba21316ddebb04:
------
##[endgroup]
Setting extra environment values for docker:  --env ENABLE_GCC_CODEGEN=1 --env GCC_EXEC_PREFIX=/usr/lib/gcc/
[CI_JOB_NAME=x86_64-gnu-llvm-18]
---
sccache: Starting the server...
##[group]Configure the build
configure: processing command line
configure: 
configure: build.configure-args := ['--build=x86_64-unknown-linux-gnu', '--llvm-root=/usr/lib/llvm-18', '--enable-llvm-link-shared', '--set', 'rust.randomize-layout=true', '--set', 'rust.thin-lto-import-instr-limit=10', '--set', 'change-id=99999999', '--enable-verbose-configure', '--enable-sccache', '--disable-manage-submodules', '--enable-locked-deps', '--enable-cargo-native-static', '--set', 'rust.codegen-units-std=1', '--set', 'dist.compression-profile=balanced', '--dist-compression-formats=xz', '--set', 'rust.lld=false', '--disable-dist-src', '--release-channel=nightly', '--enable-debug-assertions', '--enable-overflow-checks', '--enable-llvm-assertions', '--set', 'rust.verify-llvm-ir', '--set', 'rust.codegen-backends=llvm,cranelift,gcc', '--set', 'llvm.static-libstdcpp', '--enable-new-symbol-mangling']
configure: target.x86_64-unknown-linux-gnu.llvm-config := /usr/lib/llvm-18/bin/llvm-config
configure: llvm.link-shared     := True
configure: rust.randomize-layout := True
configure: rust.thin-lto-import-instr-limit := 10
---
  Downloaded boml v0.3.1
   Compiling boml v0.3.1
   Compiling y v0.1.0 (/checkout/compiler/rustc_codegen_gcc/build_system)
    Finished `release` profile [optimized] target(s) in 3.73s
     Running `/checkout/obj/build/x86_64-unknown-linux-gnu/stage1-codegen/x86_64-unknown-linux-gnu/release/y test --use-system-gcc --use-backend gcc --out-dir /checkout/obj/build/x86_64-unknown-linux-gnu/stage1-tools/cg_gcc --release --mini-tests --std-tests`
Using system GCC
[BUILD] example
[AOT] mini_core_hello_world
/checkout/obj/build/x86_64-unknown-linux-gnu/stage1-tools/cg_gcc/mini_core_hello_world
abc
---
---- [run-make] tests/run-make/alloc-no-oom-handling stdout ----

error: rmake recipe failed to complete
status: exit status: 1
command: cd "/checkout/obj/build/x86_64-unknown-linux-gnu/test/run-make/alloc-no-oom-handling/rmake_out" && env -u RUSTFLAGS AR="ar" CC="cc" CC_DEFAULT_FLAGS="-ffunction-sections -fdata-sections -fPIC -m64" CXX="c++" CXX_DEFAULT_FLAGS="-ffunction-sections -fdata-sections -fPIC -m64" HOST_RPATH_DIR="/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib" LD_LIBRARY_PATH="/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-bootstrap-tools/x86_64-unknown-linux-gnu/release/deps:/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/lib:/checkout/obj/build/x86_64-unknown-linux-gnu/stage2-tools-bin:/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/x86_64-unknown-linux-gnu/lib" LD_LIB_PATH_ENVVAR="LD_LIBRARY_PATH" LLVM_BIN_DIR="/usr/lib/llvm-18/bin" LLVM_COMPONENTS="aarch64 aarch64asmparser aarch64codegen aarch64desc aarch64disassembler aarch64info aarch64utils aggressiveinstcombine all all-targets amdgpu amdgpuasmparser amdgpucodegen amdgpudesc amdgpudisassembler amdgpuinfo amdgputargetmca amdgpuutils analysis arm armasmparser armcodegen armdesc armdisassembler arminfo armutils asmparser asmprinter avr avrasmparser avrcodegen avrdesc avrdisassembler avrinfo binaryformat bitreader bitstreamreader bitwriter bpf bpfasmparser bpfcodegen bpfdesc bpfdisassembler bpfinfo cfguard codegen codegentypes core coroutines coverage debuginfobtf debuginfocodeview debuginfodwarf debuginfogsym debuginfologicalview debuginfomsf debuginfopdb demangle dlltooldriver dwarflinker dwarflinkerclassic dwarflinkerparallel dwp engine executionengine extensions filecheck frontenddriver frontendhlsl frontendoffloading frontendopenacc frontendopenmp fuzzercli fuzzmutate globalisel hexagon hexagonasmparser hexagoncodegen hexagondesc hexagondisassembler hexagoninfo hipstdpar instcombine instrumentation interfacestub interpreter ipo irprinter irreader jitlink lanai lanaiasmparser lanaicodegen lanaidesc lanaidisassembler lanaiinfo libdriver lineeditor linker loongarch loongarchasmparser loongarchcodegen loongarchdesc loongarchdisassembler loongarchinfo lto m68k m68kasmparser m68kcodegen m68kdesc m68kdisassembler m68kinfo mc mca mcdisassembler mcjit mcparser mips mipsasmparser mipscodegen mipsdesc mipsdisassembler mipsinfo mirparser msp430 msp430asmparser msp430codegen msp430desc msp430disassembler msp430info native nativecodegen nvptx nvptxcodegen nvptxdesc nvptxinfo objcarcopts objcopy object objectyaml option orcdebugging orcjit orcshared orctargetprocess passes perfjitevents powerpc powerpcasmparser powerpccodegen powerpcdesc powerpcdisassembler powerpcinfo profiledata remarks riscv riscvasmparser riscvcodegen riscvdesc riscvdisassembler riscvinfo riscvtargetmca runtimedyld scalaropts selectiondag sparc sparcasmparser sparccodegen sparcdesc sparcdisassembler sparcinfo support symbolize systemz systemzasmparser systemzcodegen systemzdesc systemzdisassembler systemzinfo tablegen target targetparser textapi textapibinaryreader transformutils ve veasmparser vecodegen vectorize vedesc vedisassembler veinfo webassembly webassemblyasmparser webassemblycodegen webassemblydesc webassemblydisassembler webassemblyinfo webassemblyutils windowsdriver windowsmanifest x86 x86asmparser x86codegen x86desc x86disassembler x86info x86targetmca xcore xcorecodegen xcoredesc xcoredisassembler xcoreinfo xray xtensa xtensaasmparser xtensacodegen xtensadesc xtensadisassembler xtensainfo" LLVM_FILECHECK="/usr/lib/llvm-18/bin/FileCheck" NODE="/usr/bin/node" PYTHON="/usr/bin/python3" RUSTC="/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" RUSTDOC="/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustdoc" SOURCE_ROOT="/checkout" TARGET="x86_64-unknown-linux-gnu" TARGET_RPATH_DIR="/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/x86_64-unknown-linux-gnu/lib" TARGET_RPATH_ENV="/checkout/obj/build/x86_64-unknown-linux-gnu/test/run-make/alloc-no-oom-handling/rmake_out:/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-bootstrap-tools/x86_64-unknown-linux-gnu/release/deps:/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/lib" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/run-make/alloc-no-oom-handling/rmake"
--- stderr -------------------------------
command failed at line 14
command failed at line 14
Command { cmd: LD_LIBRARY_PATH="/checkout/obj/build/x86_64-unknown-linux-gnu/test/run-make/alloc-no-oom-handling/rmake_out:/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib:/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-bootstrap-tools/x86_64-unknown-linux-gnu/release/deps:/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/lib:/checkout/obj/build/x86_64-unknown-linux-gnu/stage2-tools-bin:/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/x86_64-unknown-linux-gnu/lib" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/run-make/alloc-no-oom-handling/rmake_out" "--edition" "2021" "-Dwarnings" "--crate-type" "rlib" "/checkout/library/alloc/src/lib.rs" "--cfg" "no_global_oom_handling", stdin_buf: None, stdin: None, stdout: None, stderr: None, drop_bomb: DropBomb { command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc", defused: true, armed_location: Location { file: "/checkout/tests/run-make/alloc-no-oom-handling/rmake.rs", line: 8, col: 5 } }, already_executed: true }
output status: `exit status: 1`
=== STDOUT ===


=== STDERR ===
error[E0635]: unknown feature `string_replace_in_place`

[bors]

☔ The latest upstream changes (presumably #130674) made this pull request unmergeable. Please resolve the merge conflicts.

[alex-semenyuk]

@WilliamVenner
From wg-triage. Do you have any updates on this PR?