wireproto: define and implement HTTP handshake to upgrade protocol
When clients connect to repositories over HTTP, they issue a request
to the well-known URL "?cmd=capabilities" to fetch the repository
capabilities. This is the handshake portion of the HTTP protocol.
This commit defines a mechanism to use that HTTP request to return
information about modern server features.
If a client sends an X-HgUpgrade-* header containing a list of
client-supported API names, the server responds with a response
containing information about available services. This includes
the normal capabilities string. So if the server doesn't support
any newer services, the client can easily fall back.
By advertising supported services from clients, server operators
can see and log what client support exists in the wild. This will
also help with debugging.
The response contains the base path to API services. We know there
are potential issues with the <repo>/api/ URL space conflicting with
hgwebdir and subrepos. By making the API URL dynamic from the
perspective of the client, the URL for APIs is not subject to backwards
compatibility concerns - at least as long as a ?cmd=capabilities request
is made.
We've also defined the ``cbor`` client capability for the X-HgProto-*
header. This MUST be sent in order to get the modern response from
"?cmd=capabilities". During implementation, I initially always sent
an application/mercurial-cbor response. However, the handshake
mechanism will be more future compatible if the client is in charge
of which formats to request. We already perform content negotiation
from X-HgProto-*, so keying off this for the capabilities response
feels appropriate.
In addition, I initially used application/cbor. However, it is
conceivable that a non-Mercurial server could serve application/cbor.
To rule out this possibility, I've invented a new media type that
is Mercurial specific and can't be confused for generic CBOR.
Differential Revision: https://phab.mercurial-scm.org/D3242
#require symlink execbit
$ tellmeabout() {
> if [ -h $1 ]; then
> echo $1 is a symlink:
> $TESTDIR/readlink.py $1
> elif [ -x $1 ]; then
> echo $1 is an executable file with content:
> cat $1
> else
> echo $1 is a plain file with content:
> cat $1
> fi
> }
$ hg init test1
$ cd test1
$ echo a > a
$ hg ci -Aqmadd
$ chmod +x a
$ hg ci -mexecutable
$ hg up -q 0
$ rm a
$ ln -s symlink a
$ hg ci -msymlink
created new head
Symlink is local parent, executable is other:
$ hg merge --debug
searching for copies back to rev 1
resolving manifests
branchmerge: True, force: False, partial: False
ancestor: c334dc3be0da, local: 521a1e40188f+, remote: 3574f3e69b1c
preserving a for resolve of a
a: versions differ -> m (premerge)
picked tool ':merge' for a (binary False symlink True changedelete False)
merging a
my a@521a1e40188f+ other a@3574f3e69b1c ancestor a@c334dc3be0da
warning: internal :merge cannot merge symlinks for a
warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
0 files updated, 0 files merged, 0 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
[1]
$ tellmeabout a
a is a symlink:
a -> symlink
$ hg resolve a --tool internal:other
(no more unresolved files)
$ tellmeabout a
a is an executable file with content:
a
$ hg st
M a
? a.orig
Symlink is other parent, executable is local:
$ hg update -C 1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg merge --debug --tool :union
searching for copies back to rev 1
resolving manifests
branchmerge: True, force: False, partial: False
ancestor: c334dc3be0da, local: 3574f3e69b1c+, remote: 521a1e40188f
preserving a for resolve of a
a: versions differ -> m (premerge)
picked tool ':union' for a (binary False symlink True changedelete False)
merging a
my a@3574f3e69b1c+ other a@521a1e40188f ancestor a@c334dc3be0da
warning: internal :union cannot merge symlinks for a
warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
0 files updated, 0 files merged, 0 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
[1]
$ tellmeabout a
a is an executable file with content:
a
$ hg update -C 1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg merge --debug --tool :merge3
searching for copies back to rev 1
resolving manifests
branchmerge: True, force: False, partial: False
ancestor: c334dc3be0da, local: 3574f3e69b1c+, remote: 521a1e40188f
preserving a for resolve of a
a: versions differ -> m (premerge)
picked tool ':merge3' for a (binary False symlink True changedelete False)
merging a
my a@3574f3e69b1c+ other a@521a1e40188f ancestor a@c334dc3be0da
warning: internal :merge3 cannot merge symlinks for a
warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
0 files updated, 0 files merged, 0 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
[1]
$ tellmeabout a
a is an executable file with content:
a
$ hg update -C 1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg merge --debug --tool :merge-local
searching for copies back to rev 1
resolving manifests
branchmerge: True, force: False, partial: False
ancestor: c334dc3be0da, local: 3574f3e69b1c+, remote: 521a1e40188f
preserving a for resolve of a
a: versions differ -> m (premerge)
picked tool ':merge-local' for a (binary False symlink True changedelete False)
merging a
my a@3574f3e69b1c+ other a@521a1e40188f ancestor a@c334dc3be0da
warning: internal :merge-local cannot merge symlinks for a
0 files updated, 0 files merged, 0 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
[1]
$ tellmeabout a
a is an executable file with content:
a
$ hg update -C 1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg merge --debug --tool :merge-other
searching for copies back to rev 1
resolving manifests
branchmerge: True, force: False, partial: False
ancestor: c334dc3be0da, local: 3574f3e69b1c+, remote: 521a1e40188f
preserving a for resolve of a
a: versions differ -> m (premerge)
picked tool ':merge-other' for a (binary False symlink True changedelete False)
merging a
my a@3574f3e69b1c+ other a@521a1e40188f ancestor a@c334dc3be0da
warning: internal :merge-other cannot merge symlinks for a
0 files updated, 0 files merged, 0 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
[1]
$ tellmeabout a
a is an executable file with content:
a
Update to link without local change should get us a symlink (issue3316):
$ hg up -C 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg up
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
updated to "521a1e40188f: symlink"
1 other heads for branch "default"
$ hg st
? a.orig
Update to link with local change should cause a merge prompt (issue3200):
$ hg up -Cq 0
$ echo data > a
$ HGMERGE= hg up -y --debug
searching for copies back to rev 2
resolving manifests
branchmerge: False, force: False, partial: False
ancestor: c334dc3be0da, local: c334dc3be0da+, remote: 521a1e40188f
preserving a for resolve of a
a: versions differ -> m (premerge)
(couldn't find merge tool hgmerge|tool hgmerge can't handle symlinks) (re)
no tool found to merge a
picked tool ':prompt' for a (binary False symlink True changedelete False)
keep (l)ocal [working copy], take (o)ther [destination], or leave (u)nresolved for a? u
0 files updated, 0 files merged, 0 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges
updated to "521a1e40188f: symlink"
1 other heads for branch "default"
[1]
$ hg diff --git
diff --git a/a b/a
old mode 120000
new mode 100644
--- a/a
+++ b/a
@@ -1,1 +1,1 @@
-symlink
\ No newline at end of file
+data
Test only 'l' change - happens rarely, except when recovering from situations
where that was what happened.
$ hg init test2
$ cd test2
$ printf base > f
$ hg ci -Aqm0
$ echo file > f
$ echo content >> f
$ hg ci -qm1
$ hg up -qr0
$ rm f
$ ln -s base f
$ hg ci -qm2
$ hg merge
merging f
warning: internal :merge cannot merge symlinks for f
warning: conflicts while merging f! (edit, then use 'hg resolve --mark')
0 files updated, 0 files merged, 0 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
[1]
$ tellmeabout f
f is a symlink:
f -> base
$ hg up -Cqr1
$ hg merge
merging f
warning: internal :merge cannot merge symlinks for f
warning: conflicts while merging f! (edit, then use 'hg resolve --mark')
0 files updated, 0 files merged, 0 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
[1]
$ tellmeabout f
f is a plain file with content:
file
content
$ cd ..
Test removed 'x' flag merged with change to symlink
$ hg init test3
$ cd test3
$ echo f > f
$ chmod +x f
$ hg ci -Aqm0
$ chmod -x f
$ hg ci -qm1
$ hg up -qr0
$ rm f
$ ln -s dangling f
$ hg ci -qm2
$ hg merge
merging f
warning: internal :merge cannot merge symlinks for f
warning: conflicts while merging f! (edit, then use 'hg resolve --mark')
0 files updated, 0 files merged, 0 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
[1]
$ tellmeabout f
f is a symlink:
f -> dangling
$ hg up -Cqr1
$ hg merge
merging f
warning: internal :merge cannot merge symlinks for f
warning: conflicts while merging f! (edit, then use 'hg resolve --mark')
0 files updated, 0 files merged, 0 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
[1]
$ tellmeabout f
f is a plain file with content:
f
Test removed 'x' flag merged with content change - both ways
$ hg up -Cqr0
$ echo change > f
$ hg ci -qm3
$ hg merge -r1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ tellmeabout f
f is a plain file with content:
change
$ hg up -qCr1
$ hg merge -r3
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ tellmeabout f
f is a plain file with content:
change
$ cd ..
Test merge with no common ancestor:
a: just different
b: x vs -, different (cannot calculate x, cannot ask merge tool)
c: x vs -, same (cannot calculate x, merge tool is no good)
d: x vs l, different
e: x vs l, same
f: - vs l, different
g: - vs l, same
h: l vs l, different
(where same means the filelog entry is shared and there thus is an ancestor!)
$ hg init test4
$ cd test4
$ echo 0 > 0
$ hg ci -Aqm0
$ echo 1 > a
$ echo 1 > b
$ chmod +x b
$ echo 1 > bx
$ chmod +x bx
$ echo x > c
$ chmod +x c
$ echo 1 > d
$ chmod +x d
$ printf x > e
$ chmod +x e
$ echo 1 > f
$ printf x > g
$ ln -s 1 h
$ hg ci -qAm1
$ hg up -qr0
$ echo 2 > a
$ echo 2 > b
$ echo 2 > bx
$ chmod +x bx
$ echo x > c
$ ln -s 2 d
$ ln -s x e
$ ln -s 2 f
$ ln -s x g
$ ln -s 2 h
$ hg ci -Aqm2
$ hg merge
merging a
warning: cannot merge flags for b without common ancestor - keeping local flags
merging b
merging bx
warning: cannot merge flags for c without common ancestor - keeping local flags
merging d
warning: internal :merge cannot merge symlinks for d
warning: conflicts while merging d! (edit, then use 'hg resolve --mark')
merging f
warning: internal :merge cannot merge symlinks for f
warning: conflicts while merging f! (edit, then use 'hg resolve --mark')
merging h
warning: internal :merge cannot merge symlinks for h
warning: conflicts while merging h! (edit, then use 'hg resolve --mark')
warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
warning: conflicts while merging b! (edit, then use 'hg resolve --mark')
warning: conflicts while merging bx! (edit, then use 'hg resolve --mark')
3 files updated, 0 files merged, 0 files removed, 6 files unresolved
use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
[1]
$ hg resolve -l
U a
U b
U bx
U d
U f
U h
$ tellmeabout a
a is a plain file with content:
<<<<<<< working copy: 0c617753b41b - test: 2
2
=======
1
>>>>>>> merge rev: 2e60aa20b912 - test: 1
$ tellmeabout b
b is a plain file with content:
<<<<<<< working copy: 0c617753b41b - test: 2
2
=======
1
>>>>>>> merge rev: 2e60aa20b912 - test: 1
$ tellmeabout c
c is a plain file with content:
x
$ tellmeabout d
d is a symlink:
d -> 2
$ tellmeabout e
e is a symlink:
e -> x
$ tellmeabout f
f is a symlink:
f -> 2
$ tellmeabout g
g is a symlink:
g -> x
$ tellmeabout h
h is a symlink:
h -> 2
$ hg up -Cqr1
$ hg merge
merging a
warning: cannot merge flags for b without common ancestor - keeping local flags
merging b
merging bx
warning: cannot merge flags for c without common ancestor - keeping local flags
merging d
warning: internal :merge cannot merge symlinks for d
warning: conflicts while merging d! (edit, then use 'hg resolve --mark')
merging f
warning: internal :merge cannot merge symlinks for f
warning: conflicts while merging f! (edit, then use 'hg resolve --mark')
merging h
warning: internal :merge cannot merge symlinks for h
warning: conflicts while merging h! (edit, then use 'hg resolve --mark')
warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
warning: conflicts while merging b! (edit, then use 'hg resolve --mark')
warning: conflicts while merging bx! (edit, then use 'hg resolve --mark')
3 files updated, 0 files merged, 0 files removed, 6 files unresolved
use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
[1]
$ tellmeabout a
a is a plain file with content:
<<<<<<< working copy: 2e60aa20b912 - test: 1
1
=======
2
>>>>>>> merge rev: 0c617753b41b - test: 2
$ tellmeabout b
b is an executable file with content:
<<<<<<< working copy: 2e60aa20b912 - test: 1
1
=======
2
>>>>>>> merge rev: 0c617753b41b - test: 2
$ tellmeabout c
c is an executable file with content:
x
$ tellmeabout d
d is an executable file with content:
1
$ tellmeabout e
e is an executable file with content:
x (no-eol)
$ tellmeabout f
f is a plain file with content:
1
$ tellmeabout g
g is a plain file with content:
x (no-eol)
$ tellmeabout h
h is a symlink:
h -> 1
$ cd ..