Differences between revisions 13 and 18 (spanning 5 versions)

Simple

Add the following line to your Makefile

HGVERSION:= $(shell hg parents --template 'hgid: {node|short}')

and

-DHGVERSION="\"${HGVERSION}\""

to your CPPFLAGS. Now one can use the define HGVERSION inside the code.

Rebuild files using HGVERSION

Make rebuilds targets only if one of the dependencies is newer. That means even if the version has changed, due to a change somewhere, files using HGVERSION will not be rebuilt automatically. To overcome this, add a new dependency in the Makefile to update these files:

version.o: hgstamp
.PHONY: update_hgstamp
hgstamp: update_hgstamp
        [ -f $@ ] || touch $@
        echo $(HGVERSION) | cmp -s $@ - || echo $(HGVERSION) > $@

You will see in this example version.o has the extra dependency on the file hgstamp.

How this works:

The rule for the hgstamp target specifies the prerequisite update_hgstamp.
The update_hgstamp target is marked as a phony target (see make manual) which forces the recipe for hgstamp to be executed every time.
However make only forces version.o to be remade when the modification time of the hgstamp file changes and this only happens when the hgstamp recipe actually updates the content of the hgstamp file--which only happens if and only if the version has really changed.

See https://bitbucket.org/follower/hgversion-handling for an example of a correctly functioning Makefile.

It is essential that the hgstamp target is not marked as phony.

If hgstamp is marked as phony then the hgstamp file will be considered out of date every time make is run--which will cause version.o and everything that depends on version.o to be rebuilt every time. (Revisions 14-17 of this page used .PHONY for the wrong target causing rebuilds every time.)

Autotools

If you are using automake add the following lines to your Makefile.am:

HGVERSION:= $(shell hg -R $(top_srcdir) parents --template 'hgid: {node|short}' 2> /dev/null || grep node $(top_srcdir)/.hg_archival.txt 2> /dev/null || true )
AM_CPPFLAGS = -DHGVERSION="\"${HGVERSION}\""

version.o: hgstamp
.PHONY: update_hgstamp
hgstamp: update_hgstamp
        [ -f $@ ] || touch $@
        echo $(HGVERSION) | cmp -s $@ - || echo $(HGVERSION) > $@

The definition of HGVERSION is more robust here. It tries to get the version in the following order

hg parents, the -R option is added to prevent hg from searching in lower directories in case we don't have a repository
grabbing it from .hg_archival.txt, in case we are using a tarball made by hg archive
undefined

LaTeX

Just add the following lines to your Makefile

HGID:=$(shell hg parents -R . --template "{node|short}" | sed 's/.*/\\renewcommand{\\hgid}{&}/')
.PHONY: update_hgid
hgid.tex: update_hgid
        [ -f $@ ] || touch $@
        echo '$(HGID)' | cmp -s $@ - || echo '$(HGID)' > $@

and this lines to your main tex file:

\newcommand{\hgid}{null}
\input{hgid}

Now one can use the command \hgid to get the version everywhere.

CategoryHowTo

-  ⇤ ← Revision 13 as of 2010-02-22 11:19:30 → 
  Size: 2228
  Editor: JunghansChristoph
  Comment: better make rule (thanks to Teemu Murtola)
+   ← Revision 18 as of 2015-08-10 06:26:49 → ⇥
  Size: 3283
  Editor: follower
  Comment: Correct misuse of .PHONY with wrong target introduced in Revision 14. Fix wrong target name in LaTeX example.
-Deletions are marked like this.
+Additions are marked like this.
 Line 15:
-Make rebuilds targets only if one of the dependencies is newer. That means even if the version has changed, due to a change somewhere, files using HGVERSION will not be rebuild automatically. To overcome this add new dependency in the Makefile to updated these files:
+Make rebuilds targets only if one of the dependencies is newer. That means even if the version has changed, due to a change somewhere, files using HGVERSION will not be rebuilt automatically. To overcome this, add a new dependency in the Makefile to update these files:
 Line 19:
-hgstamp: dummy
+.PHONY: update_hgstamp
hgstamp: update_hgstamp
-Line 22:
+Line 23:
+}}}
You will see in this example `version.o` has the extra dependency on the file `hgstamp`.
-Line 23:
+Line 26:
-dummy: ;
+How this works:
 1. The rule for the `hgstamp` target specifies the prerequisite `update_hgstamp`.
 1. The `update_hgstamp` target is marked as a ''phony target'' (see [[http://www.gnu.org/software/make/manual/html_node/Phony-Targets.html|make manual]]) which forces the recipe for `hgstamp` to be executed every time.
 1. '''''However''''' `make` only forces `version.o` to be remade when the modification time of the `hgstamp` ''file'' changes and ''this'' only happens when the `hgstamp` recipe ''actually'' updates the content of the `hgstamp` file--which only happens if and only if the version has ''really'' changed.

See https://bitbucket.org/follower/hgversion-handling for an example of a correctly functioning Makefile.

{{{#!wiki caution
It is ''essential'' that the `hgstamp` target is '''''not''''' marked as phony.

If `hgstamp` is marked as phony then the `hgstamp` file will be considered out of date every time `make` is run--which will cause `version.o` and everything that depends on `version.o` to be rebuilt ''every time''. (Revisions 14-17 of this page used `.PHONY` for the wrong target causing rebuilds every time.)
-Line 25:
+Line 38:
-In this example version.o has the extra dependency hgstamp. The hgstamp rule updates hgstamp if and only if the version has ''really'' changed. 
To make sure the hgstamp rule will be executed every time, it depends on a dummy rule, which does nothing.
-Line 29:
+Line 40:
-If you are using automake add the following lines to your Makefile.am
+If you are using automake add the following lines to your Makefile.am:
-Line 36:
+Line 47:
-hgstamp: dummy
+.PHONY: update_hgstamp
hgstamp: update_hgstamp
-Line 39:
+Line 51:
-dummy: ;
-Line 44:
+Line 54:
- * hg parents, the -R option is added to prevent hg to search in lower directories in the case we don't have a repository
+ * hg parents, the -R option is added to prevent hg from searching in lower directories in case we don't have a repository
-Line 49:
+Line 59:
-Just a add the following lines to your Makefile
+Just add the following lines to your Makefile
-Line 53:
+Line 63:
-hgid.tex: dummy
+.PHONY: update_hgid
hgid.tex: update_hgid
-Line 56:
+Line 67:
-dummy: ;
-Line 59:
+Line 68:
-and this lines to your main tex file
+and this lines to your main tex file:
-Line 65:
+Line 74:
-now one can use the command \hgid to get the version everywhere.
+Now one can use the command \hgid to get the version everywhere.

Diff for "VersioningWithMake"

Simple

Rebuild files using HGVERSION

Autotools

LaTeX