`process_cov` throws `BoundsError: attempt to access 8-codeunit String at index [1:9]`

[nickrobinson251]

BoundsError: attempt to access 8-codeunit String at index [1:9]
Stacktrace:
  [1] checkbounds
    @ ./strings/basic.jl:216 [inlined]
  [2] getindex
    @ ./strings/string.jl:265 [inlined]
  [3] process_cov(filename::String, folder::String)
    @ CoverageTools ~/.julia/packages/CoverageTools/JSYpL/src/CoverageTools.jl:133
  [4] process_file(filename::String, folder::String)
    @ CoverageTools ~/.julia/packages/CoverageTools/JSYpL/src/CoverageTools.jl:232
  [5] process_folder(folder::String)
    @ CoverageTools ~/.julia/packages/CoverageTools/JSYpL/src/CoverageTools.jl:258
  [6] process_folder(folder::String) (repeats 2 times)
    @ CoverageTools ~/.julia/packages/CoverageTools/JSYpL/src/CoverageTools.jl:264
  [7] (::var"#3#4")()
    @ Main ~/test_retestitems.jl:39
  [8] with_logstate(f::Function, logstate::Any)
    @ Base.CoreLogging ./logging.jl:511
  [9] with_logger(f::Function, logger::Logging.ConsoleLogger)
    @ Base.CoreLogging ./logging.jl:623
 [10] top-level scope
    @ ~/script.jl:38

CoverageTools.jl/src/CoverageTools.jl

Line 133 in 9d8fba3

cov_segment = line[1:9]

Where ~/script.jl:38 looks like:

    Logging.with_logger(Logging.ConsoleLogger(stderr, Logging.Warn)) do
        src_coverage = Coverage.process_folder("src")
        LCOV.writefile("lcov.info", src_coverage)
    end

[nickrobinson251]

also seen this when using julia-actions/julia-processcoverage@v1 with ReTestItems.jl CI
Example: https://github.com/JuliaTesting/ReTestItems.jl/actions/runs/6830744028/job/18579153092?pr=117
Logs:

Run julia-actions/julia-processcoverage@v1
  with:
    directories: src,ext
  env:
    JULIA_NUM_THREADS: 2
    JULIA_PKG_SERVER_REGISTRY_PREFERENCE: eager

Run julia --color=yes "$GITHUB_ACTION_PATH"/main.jl
  julia --color=yes "$GITHUB_ACTION_PATH"/main.jl
  shell: /bin/bash --noprofile --norc -e -o pipefail {0}
  env:
    JULIA_NUM_THREADS: 2
    JULIA_PKG_SERVER_REGISTRY_PREFERENCE: eager
    INPUT_DIRECTORIES: src,ext
  Activating new project at `~/.julia/environments/coveragetempenv`
    Updating registry at `~/.julia/registries/General.toml`
   Resolving package versions...
   Installed CoverageTools ─ v1.3.0
    Updating `~/.julia/environments/coveragetempenv/Project.toml`
  [c36e975a] + CoverageTools v1.3.0
    Updating `~/.julia/environments/coveragetempenv/Manifest.toml`
  [c36e975a] + CoverageTools v1.3.0
Precompiling project...
  ✓ CoverageTools
  1 dependency successfully precompiled in 1 seconds
[ Info: CoverageTools.process_folder: Searching src for .jl files...
[ Info: CoverageTools.process_file: Detecting coverage for src/ReTestItems.jl
[ Info: CoverageTools.process_cov: processing src/ReTestItems.jl.6082.cov
[ Info: CoverageTools.process_cov: processing src/ReTestItems.jl.6089.cov
...
...
[ Info: CoverageTools.process_cov: processing src/macros.jl.6509.cov
[ Info: CoverageTools.process_cov: processing src/macros.jl.6518.cov
[ Info: CoverageTools.process_cov: processing src/macros.jl.6522.cov
ERROR: LoadError: BoundsError: attempt to access 6-codeunit String at index [1:9]
Stacktrace:
  [1] checkbounds
    @ ./strings/basic.jl:216 [inlined]
  [2] getindex
    @ ./strings/string.jl:276 [inlined]
  [3] process_cov(filename::String, folder::SubString{String})
    @ CoverageTools ~/.julia/packages/CoverageTools/JSYpL/src/CoverageTools.jl:133
  [4] process_file(filename::String, folder::SubString{String})
    @ CoverageTools ~/.julia/packages/CoverageTools/JSYpL/src/CoverageTools.jl:232
  [5] process_folder(folder::SubString{String})
    @ CoverageTools ~/.julia/packages/CoverageTools/JSYpL/src/CoverageTools.jl:258
  [6] mapreduce_first
    @ ./reduce.jl:419 [inlined]
  [7] _mapreduce(f::typeof(process_folder), op::typeof(vcat), #unused#::IndexLinear, A::Vector{SubString{String}})
    @ Base ./reduce.jl:430
  [8] _mapreduce_dim(f::Function, op::Function, #unused#::Base._InitialValue, A::Vector{SubString{String}}, #unused#::Colon)
    @ Base ./reducedim.jl:365
  [9] #mapreduce#800
    @ ./reducedim.jl:357 [inlined]
 [10] mapreduce(f::Function, op::Function, A::Vector{SubString{String}})
    @ Base ./reducedim.jl:357
 [11] top-level scope
    @ ~/work/_actions/julia-actions/julia-processcoverage/v1/main.jl:19
in expression starting at /Users/runner/work/_actions/julia-actions/julia-processcoverage/v1/main.jl:19
Error: Process completed with exit code 1.

[pxl-th]

Observed with AMDGPU.jl in CI:
https://buildkite.com/julialang/amdgpu-dot-jl/builds/2235#018cab31-c8eb-41b1-bd2a-0087ff8c4af6