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Differential D9006

chg: make is possible to call by default an hg binary located next to chg
ClosedPublic

Authored by valentin.gatienbaron on Sep 10 2020, 2:12 PM.

Details

Reviewers
marmoute
pulkit
Group Reviewers
hg-reviewers
Commits
rHG4c8d9b53b1c7: chg: make is possible to call by default an hg binary located next to chg
rHG50fa4f631ef6: chg: make is possible to call by default an hg binary located next to chg
rHGeb443f7cbc2c: chg: make is possible to call by default an hg binary located next to chg
Summary

When a single version of hg is in use and it's in the PATH, using chg
is just a matter of calling chg.

But when there are multiple installations of hg+chg around, and hg is
referred to with an absolute path, using chg is more annoying because
it requires both changing the invocation to hg to use chg, but also
setting CHGHG.

Currently, we set HGPATH when we build chg to remove the need to set
CHGHG in the previous paragraph. But that means chg now hardcodes its
installation path, which makes the installation not relocatable. Hence
this proposal to make chg find ./hg relative to itself (as opposed to
CHGHG=./hg which find hg relative to cwd).

This only works on linux as written, but since it's opt-in, it sounds
fine.

Tested by hand, as I'm not sure how else to test this.

Diff Detail

Repository
rHG Mercurial
Lint
Automatic diff as part of commit; lint not applicable.
Unit
Automatic diff as part of commit; unit tests not applicable.

Event Timeline

pulkit added subscribers: yuja, pulkit.Sep 11 2020, 5:15 AM

@yuja something which should not miss your eyes I guess :)

marmoute added a subscriber: marmoute.Sep 17 2020, 3:58 AM

The behavior and the code looks good to me. I guess we should document the variable and the behavior somewhere. However I am not sure of where that might be. @yuya do you know where the chg documentation lives ?

marmoute accepted this revision.Sep 17 2020, 4:01 AM
pulkit accepted this revision.Sep 24 2020, 3:38 AM
This revision is now accepted and ready to land.Sep 24 2020, 3:38 AM

Revision Contents
Changeset List

PathPackages
Mcontrib/chg/Makefile (3 lines)
Mcontrib/chg/README (8 lines)
Mcontrib/chg/chg.c (33 lines)

Diff 22826

contrib/chg/Makefile

TARGET = chg TARGET = chg
SRCS = chg.c hgclient.c procutil.c util.c SRCS = chg.c hgclient.c procutil.c util.c
OBJS = $(SRCS:.c=.o) OBJS = $(SRCS:.c=.o)
CFLAGS ?= -O2 -Wall -Wextra -pedantic -g CFLAGS ?= -O2 -Wall -Wextra -pedantic -g
CPPFLAGS ?= -D_FORTIFY_SOURCE=2 -D_GNU_SOURCE CPPFLAGS ?= -D_FORTIFY_SOURCE=2 -D_GNU_SOURCE
override CFLAGS += -std=gnu99 override CFLAGS += -std=gnu99
ifdef HGPATH ifdef HGPATH
override CPPFLAGS += -DHGPATH=\"$(HGPATH)\" override CPPFLAGS += -DHGPATH=\"$(HGPATH)\"
endif endif
ifdef HGPATHREL
override CPPFLAGS += -DHGPATHREL=\"$(HGPATHREL)\"
endif
DESTDIR = DESTDIR =
PREFIX = /usr/local PREFIX = /usr/local
MANDIR = $(PREFIX)/share/man/man1 MANDIR = $(PREFIX)/share/man/man1
.PHONY: all .PHONY: all
all: $(TARGET) all: $(TARGET)

contrib/chg/README

background command server. background command server.
The following variables are available for testing: The following variables are available for testing:
* CHGDEBUG enables debug messages. * CHGDEBUG enables debug messages.
* CHGSOCKNAME specifies the socket path of the background cmdserver. * CHGSOCKNAME specifies the socket path of the background cmdserver.
* CHGTIMEOUT specifies how many seconds chg will wait before giving up * CHGTIMEOUT specifies how many seconds chg will wait before giving up
connecting to a cmdserver. If it is 0, chg will wait forever. Default: 60 connecting to a cmdserver. If it is 0, chg will wait forever. Default: 60
Build environment variables:
* HGPATH: the path to the hg executable to call when CHGHG and HG are not set,
instead of "hg"
* HGPATHREL=1: when CHGHG and HG are not set, the hg executable will be ./hg
relative to the chg executable. Only works on linux, falls back to "hg"
otherwise.

contrib/chg/chg.c

if (r < 0 || (size_t)r >= sizeof(opts->sockname)) if (r < 0 || (size_t)r >= sizeof(opts->sockname))
abortmsg("too long TMPDIR or CHGSOCKNAME (r = %d)", r); abortmsg("too long TMPDIR or CHGSOCKNAME (r = %d)", r);
r = snprintf(opts->initsockname, sizeof(opts->initsockname), "%s.%u", r = snprintf(opts->initsockname, sizeof(opts->initsockname), "%s.%u",
opts->sockname, (unsigned)getpid()); opts->sockname, (unsigned)getpid());
if (r < 0 || (size_t)r >= sizeof(opts->initsockname)) if (r < 0 || (size_t)r >= sizeof(opts->initsockname))
abortmsg("too long TMPDIR or CHGSOCKNAME (r = %d)", r); abortmsg("too long TMPDIR or CHGSOCKNAME (r = %d)", r);
} }
/* If the current program is, say, /a/b/c/chg, returns /a/b/c/hg. */
static char *getrelhgcmd(void)
{
ssize_t n;
char *res, *slash;
int maxsize = 4096;
res = malloc(maxsize);
if (res == NULL)
goto cleanup;
n = readlink("/proc/self/exe", res, maxsize);
if (n < 0 || n >= maxsize)
goto cleanup;
res[n] = '\0';
slash = strrchr(res, '/');
if (slash == NULL)
goto cleanup;
/* 4 is strlen("/hg") + nul byte */
if (slash + 4 >= res + maxsize)
goto cleanup;
memcpy(slash, "/hg", 4);
return res;
cleanup:
free(res);
return NULL;
}
static const char *gethgcmd(void) static const char *gethgcmd(void)
{ {
static const char *hgcmd = NULL; static const char *hgcmd = NULL;
#ifdef HGPATHREL
int tryrelhgcmd = 1;
#else
int tryrelhgcmd = 0;
#endif
if (!hgcmd) { if (!hgcmd) {
hgcmd = getenv("CHGHG"); hgcmd = getenv("CHGHG");
if (!hgcmd || hgcmd[0] == '\0') if (!hgcmd || hgcmd[0] == '\0')
hgcmd = getenv("HG"); hgcmd = getenv("HG");
if (tryrelhgcmd && (!hgcmd || hgcmd[0] == '\0'))
hgcmd = getrelhgcmd();
if (!hgcmd || hgcmd[0] == '\0') if (!hgcmd || hgcmd[0] == '\0')
#ifdef HGPATH #ifdef HGPATH
hgcmd = (HGPATH); hgcmd = (HGPATH);
#else #else
hgcmd = "hg"; hgcmd = "hg";
#endif #endif
} }
return hgcmd; return hgcmd;