Issue 1:
System is an M1 Macbook Air. Julia info:

julia> versioninfo()
Julia Version 1.7.0-rc1
Commit 9eade6195e (2021-09-12 06:45 UTC)
Platform Info:
OS: macOS (arm64-apple-darwin20.5.0)
CPU: Apple M1
WORD_SIZE: 64
LIBM: libopenlibm
LLVM: libLLVM-12.0.1 (ORCJIT, cyclone)

Starting from a clean installation, I did

] add DataFrames
] test DataFrames

The latter call ran many tests successfully, but then emitted a segfault as here:

Test Summary: | Pass Total
stack view=true additional tests | 2 2
PASSED: reshape.jl

signal (11): Segmentation fault: 11
in expression starting at /Users/gillam/.julia/packages/DataFrames/vuMM8/test/dataframerow.jl:12
ntuple at ./ntuple.jl:0 [inlined]
NamedTuple at /Users/gillam/.julia/packages/DataFrames/vuMM8/src/dataframerow/dataframerow.jl:427
copy at /Users/gillam/.julia/packages/DataFrames/vuMM8/src/dataframerow/dataframerow.jl:442
unknown function (ip: 0x2980b19bb)
jl_apply_generic at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
macro expansion at /Users/sabae/src/julia/usr/share/julia/stdlib/v1.7/Test/src/Test.jl:445 [inlined]
macro expansion at /Users/gillam/.julia/packages/DataFrames/vuMM8/test/dataframerow.jl:20 [inlined]
macro expansion at /Users/sabae/src/julia/usr/share/julia/stdlib/v1.7/Test/src/Test.jl:1282 [inlined]
top-level scope at /Users/gillam/.julia/packages/DataFrames/vuMM8/test/dataframerow.jl:13
jl_toplevel_eval_flex at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
jl_toplevel_eval_flex at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
jl_toplevel_eval_flex at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
jl_toplevel_eval_in at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
eval at ./boot.jl:373 [inlined]
include_string at ./loading.jl:1196
jl_apply_generic at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
_include at ./loading.jl:1253
include at ./client.jl:451
jl_apply_generic at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
top-level scope at /Users/gillam/.julia/packages/DataFrames/vuMM8/test/runtests.jl:50
jl_toplevel_eval_flex at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
jl_toplevel_eval_flex at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
jl_toplevel_eval_in at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
eval at ./boot.jl:373 [inlined]
include_string at ./loading.jl:1196
jl_apply_generic at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
_include at ./loading.jl:1253
include at ./client.jl:451
jl_apply_generic at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
do_call at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
eval_body at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
jl_interpret_toplevel_thunk at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
jl_toplevel_eval_flex at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
jl_toplevel_eval_flex at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
jl_toplevel_eval_in at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
eval at ./boot.jl:373 [inlined]
exec_options at ./client.jl:268
_start at ./client.jl:495
jfptr__start_33611 at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/sys.dylib (unknown line)
jl_apply_generic at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
true_main at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
jl_repl_entrypoint at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
Allocations: 516343408 (Pool: 513344936; Big: 2998472); GC: 1050
ERROR: Package DataFrames errored during testing (exit code: 139)

(I am surprised I'm seeing the /Users/sabae path in this output. It doesn't exist on my system.)

Re-running ] test DataFrames resulted in another segfault, although this time at a different point in the tests:

Test Summary: | Pass Total
non standard selectors | 4 4

signal (11): Segmentation fault: 11
in expression starting at /Users/gillam/.julia/packages/DataFrames/vuMM8/test/sort.jl:150
ntuple at ./ntuple.jl:0 [inlined]
DFPerm at /Users/gillam/.julia/packages/DataFrames/vuMM8/src/abstractdataframe/sort.jl:116
unknown function (ip: 0x2980fa323)
jl_apply_generic at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
ordering at /Users/gillam/.julia/packages/DataFrames/vuMM8/src/abstractdataframe/sort.jl:170
ordering at /Users/gillam/.julia/packages/DataFrames/vuMM8/src/abstractdataframe/sort.jl:212
#sortperm#754 at /Users/gillam/.julia/packages/DataFrames/vuMM8/src/abstractdataframe/sort.jl:512
unknown function (ip: 0x2980f80ab)
sortperm##kw at /Users/gillam/.julia/packages/DataFrames/vuMM8/src/abstractdataframe/sort.jl:503 [inlined]
#sort#753 at /Users/gillam/.julia/packages/DataFrames/vuMM8/src/abstractdataframe/sort.jl:438 [inlined]
sort at /Users/gillam/.julia/packages/DataFrames/vuMM8/src/abstractdataframe/sort.jl:438 [inlined]
sort at /Users/gillam/.julia/packages/DataFrames/vuMM8/src/abstractdataframe/sort.jl:438
unknown function (ip: 0x2980f440f)
jl_apply_generic at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
do_call at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
eval_body at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
eval_body at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
eval_body at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
eval_body at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
jl_interpret_toplevel_thunk at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
jl_toplevel_eval_flex at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
jl_toplevel_eval_flex at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
jl_toplevel_eval_flex at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
jl_toplevel_eval_in at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
eval at ./boot.jl:373 [inlined]
include_string at ./loading.jl:1196
jl_apply_generic at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
_include at ./loading.jl:1253
include at ./client.jl:451
jl_apply_generic at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
top-level scope at /Users/gillam/.julia/packages/DataFrames/vuMM8/test/runtests.jl:50
jl_toplevel_eval_flex at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
jl_toplevel_eval_flex at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
jl_toplevel_eval_in at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
eval at ./boot.jl:373 [inlined]
include_string at ./loading.jl:1196
jl_apply_generic at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
_include at ./loading.jl:1253
include at ./client.jl:451
jl_apply_generic at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
do_call at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
eval_body at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
jl_interpret_toplevel_thunk at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
jl_toplevel_eval_flex at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
jl_toplevel_eval_flex at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
jl_toplevel_eval_in at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
eval at ./boot.jl:373 [inlined]
exec_options at ./client.jl:268
_start at ./client.jl:495
jfptr__start_33611 at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/sys.dylib (unknown line)
jl_apply_generic at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
true_main at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
jl_repl_entrypoint at /Applications/Julia-1.7.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.7.dylib (unknown line)
Allocations: 585978915 (Pool: 582952489; Big: 3026426); GC: 1114
ERROR: Package DataFrames errored during testing (exit code: 139)

Issue 2:
“ismatch(regex, str) has been deprecated in favor of contains(str, regex)”

then later

“contains has been deprecated in favor of a more general occursin function”

It might make more sense if these two paragraphs were somehow merged. Some idiot might change all their ismatches to containss then later have to go back and change all their containss to occursins. (Yes I did! :)