[Mesa-dev] [PATCH mesa v2 2/2] meson: bring MESA_GIT_SHA1 in line with other build systems

[Eric Engestrom]

From: Eric Engestrom <eric at engestrom.ch>

Meson's vcs_tag() uses the output of `git describe`, eg.
  17.3-branchpoint-5-gfbf29c3cd15ae831e249+

Whereas the other build systems used a script that outputs only the sha1
of the HEAD commit, eg.
  fbf29c3cd1

Given that this information is used by printing it next to the version
number, there's some redundancy here, and inconsistency between build
systems.

Bring Meson in line by making it use the same script, with the added
advantage of now supporting the MESA_GIT_SHA1_OVERRIDE env var.

Signed-off-by: Eric Engestrom <eric at engestrom.ch>
---
v2: add patch 1/2 to avoid having to rebuild when nothing changed (Jordan Justen)
---
 bin/meson.build | 21 +++++++++++++++++++++
 meson.build     |  1 +
 src/meson.build |  6 ++++--
 3 files changed, 26 insertions(+), 2 deletions(-)
 create mode 100644 bin/meson.build

diff --git a/bin/meson.build b/bin/meson.build
new file mode 100644
index 00000000000000000000..b8b44baf7d03e2b0658f
--- /dev/null
+++ b/bin/meson.build
@@ -0,0 +1,21 @@
+# Copyright © 2017 Eric Engestrom
+
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+git_sha1_gen_py = files('git_sha1_gen.py')
diff --git a/meson.build b/meson.build
index 5f6dabc33ec83498e335..738ebc510ace26fd7917 100644
--- a/meson.build
+++ b/meson.build
@@ -846,4 +846,5 @@ endif
 pkg = import('pkgconfig')
 
 subdir('include')
+subdir('bin')
 subdir('src')
diff --git a/src/meson.build b/src/meson.build
index 9b1b0ae594d103a12ba2..363baf5ae5e63a70333b 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -34,9 +34,11 @@ libglsl_util = static_library(
   build_by_default : false,
 )
 
-sha1_h = vcs_tag(
-  input : 'git_sha1.h.in',
+sha1_h = custom_target(
+  'git_sha1.h',
   output : 'git_sha1.h',
+  command : [prog_python2, git_sha1_gen_py, '--output', '@OUTPUT@'],
+  build_always : true,
 )
 
 subdir('gtest')
-- 
Cheers,
  Eric