internals: document CBOR utilization
I spoke with some people at Mozilla about CBOR and they advised me
that we should be careful about the subset of CBOR we use in order
to mitigate security, performance, and compatibility concerns.
This commit establishes a document that attempts to formalize our
use of CBOR.
Its main limitations are on what types are allowed. It explicitly
enumerates which types are supported. Notable missing features
include:
* Indefinite-length arrays and maps
* Text strings (bytes all the way)
* Floats
* Date/time types
* Big integers
* Use of indefinite-length byte strings for map keys, values in
containers.
If we have a need for any of these, we can have a discussion about
them when the time comes.
Differential Revision: https://phab.mercurial-scm.org/D4412
test sparse
$ hg init myrepo
$ cd myrepo
$ cat > .hg/hgrc <<EOF
> [extensions]
> sparse=
> purge=
> strip=
> rebase=
> EOF
Config file without [section] is rejected
$ cat > bad.sparse <<EOF
> *.html
> EOF
$ hg debugsparse --import-rules bad.sparse
abort: sparse config entry outside of section: *.html
(add an [include] or [exclude] line to declare the entry type)
[255]
$ rm bad.sparse
$ echo a > index.html
$ echo x > data.py
$ echo z > readme.txt
$ cat > webpage.sparse <<EOF
> # frontend sparse profile
> [include]
> *.html
> EOF
$ cat > backend.sparse <<EOF
> # backend sparse profile
> [include]
> *.py
> EOF
$ hg ci -Aqm 'initial'
$ hg debugsparse --include '*.sparse'
Verify enabling a single profile works
$ hg debugsparse --enable-profile webpage.sparse
$ ls
backend.sparse
index.html
webpage.sparse
Verify enabling two profiles works
$ hg debugsparse --enable-profile backend.sparse
$ ls
backend.sparse
data.py
index.html
webpage.sparse
Verify disabling a profile works
$ hg debugsparse --disable-profile webpage.sparse
$ ls
backend.sparse
data.py
webpage.sparse
Verify that a profile is updated across multiple commits
$ cat > webpage.sparse <<EOF
> # frontend sparse profile
> [include]
> *.html
> EOF
$ cat > backend.sparse <<EOF
> # backend sparse profile
> [include]
> *.py
> *.txt
> EOF
$ echo foo >> data.py
$ hg ci -m 'edit profile'
$ ls
backend.sparse
data.py
readme.txt
webpage.sparse
$ hg up -q 0
$ ls
backend.sparse
data.py
webpage.sparse
$ hg up -q 1
$ ls
backend.sparse
data.py
readme.txt
webpage.sparse
Introduce a conflicting .hgsparse change
$ hg up -q 0
$ cat > backend.sparse <<EOF
> # Different backend sparse profile
> [include]
> *.html
> EOF
$ echo bar >> data.py
$ hg ci -qAm "edit profile other"
$ ls
backend.sparse
index.html
webpage.sparse
Verify conflicting merge pulls in the conflicting changes
$ hg merge 1
temporarily included 1 file(s) in the sparse checkout for merging
merging backend.sparse
merging data.py
warning: conflicts while merging backend.sparse! (edit, then use 'hg resolve --mark')
warning: conflicts while merging data.py! (edit, then use 'hg resolve --mark')
0 files updated, 0 files merged, 0 files removed, 2 files unresolved
use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
[1]
$ rm *.orig
$ ls
backend.sparse
data.py
index.html
webpage.sparse
Verify resolving the merge removes the temporarily unioned files
$ cat > backend.sparse <<EOF
> # backend sparse profile
> [include]
> *.html
> *.txt
> EOF
$ hg resolve -m backend.sparse
$ cat > data.py <<EOF
> x
> foo
> bar
> EOF
$ hg resolve -m data.py
(no more unresolved files)
$ hg ci -qAm "merge profiles"
$ ls
backend.sparse
index.html
readme.txt
webpage.sparse
$ hg cat -r . data.py
x
foo
bar
Verify stripping refreshes dirstate
$ hg strip -q -r .
$ ls
backend.sparse
index.html
webpage.sparse
Verify rebase conflicts pulls in the conflicting changes
$ hg up -q 1
$ ls
backend.sparse
data.py
readme.txt
webpage.sparse
$ hg rebase -d 2
rebasing 1:a2b1de640a62 "edit profile"
temporarily included 1 file(s) in the sparse checkout for merging
merging backend.sparse
merging data.py
warning: conflicts while merging backend.sparse! (edit, then use 'hg resolve --mark')
warning: conflicts while merging data.py! (edit, then use 'hg resolve --mark')
unresolved conflicts (see hg resolve, then hg rebase --continue)
[1]
$ rm *.orig
$ ls
backend.sparse
data.py
index.html
webpage.sparse
Verify resolving conflict removes the temporary files
$ cat > backend.sparse <<EOF
> [include]
> *.html
> *.txt
> EOF
$ hg resolve -m backend.sparse
$ cat > data.py <<EOF
> x
> foo
> bar
> EOF
$ hg resolve -m data.py
(no more unresolved files)
continue: hg rebase --continue
$ hg rebase -q --continue
$ ls
backend.sparse
index.html
readme.txt
webpage.sparse
$ hg cat -r . data.py
x
foo
bar
Test checking out a commit that does not contain the sparse profile. The
warning message can be suppressed by setting missingwarning = false in
[sparse] section of your config:
$ hg debugsparse --reset
$ hg rm *.sparse
$ hg commit -m "delete profiles"
$ hg up -q ".^"
$ hg debugsparse --enable-profile backend.sparse
$ ls
index.html
readme.txt
$ hg up tip | grep warning
warning: sparse profile 'backend.sparse' not found in rev bfcb76de99cc - ignoring it
[1]
$ ls
data.py
index.html
readme.txt
$ hg debugsparse --disable-profile backend.sparse | grep warning
warning: sparse profile 'backend.sparse' not found in rev bfcb76de99cc - ignoring it
[1]
$ cat >> .hg/hgrc <<EOF
> [sparse]
> missingwarning = false
> EOF
$ hg debugsparse --enable-profile backend.sparse
$ cd ..
#if unix-permissions
Test file permissions changing across a sparse profile change
$ hg init sparseperm
$ cd sparseperm
$ cat > .hg/hgrc <<EOF
> [extensions]
> sparse=
> EOF
$ touch a b
$ cat > .hgsparse <<EOF
> [include]
> a
> EOF
$ hg commit -Aqm 'initial'
$ chmod a+x b
$ hg commit -qm 'make executable'
$ cat >> .hgsparse <<EOF
> b
> EOF
$ hg commit -qm 'update profile'
$ hg up -q 0
$ hg debugsparse --enable-profile .hgsparse
$ hg up -q 2
$ ls -l b
-rwxr-xr-x* b (glob)
#endif