[PATCH v3 6/6] meson: add options to override build information

[Patrick Steinhardt <ps@xxxxxx>]

We inject various different kinds of build information into build
artifacts, like the version string or the commit from which Git was
built. Add options to let users explicitly override this information
with Meson.

Signed-off-by: Patrick Steinhardt <ps@xxxxxx>
---
 Documentation/meson.build |  1 +
 meson.build               | 13 +++++++++++++
 meson_options.txt         | 10 ++++++++++
 3 files changed, 24 insertions(+)

diff --git a/Documentation/meson.build b/Documentation/meson.build
index f2426ccaa30c29bd60b850eb0a9a4ab77c66a629..fca3eab1f1360a5fdeda89c1766ab8cdb3267b89 100644
--- a/Documentation/meson.build
+++ b/Documentation/meson.build
@@ -219,6 +219,7 @@ asciidoc_conf = custom_target(
   input: meson.current_source_dir() / 'asciidoc.conf.in',
   output: 'asciidoc.conf',
   depends: [git_version_file],
+  env: version_gen_environment,
 )
 
 asciidoc_common_options = [
diff --git a/meson.build b/meson.build
index 0dccebcdf16b07650d943e53643f0e09e2975cc9..be32d60e841a3055ed2bdf6fd449a48b66d94cd0 100644
--- a/meson.build
+++ b/meson.build
@@ -201,6 +201,16 @@ if get_option('sane_tool_path') != ''
   script_environment.prepend('PATH', get_option('sane_tool_path'))
 endif
 
+# The environment used by GIT-VERSION-GEN. Note that we explicitly override
+# environment variables that might be set by the user. This is by design so
+# that we always use whatever Meson has configured instead of what is present
+# in the environment.
+version_gen_environment = script_environment
+version_gen_environment.set('GIT_BUILT_FROM_COMMIT', get_option('built_from_commit'))
+version_gen_environment.set('GIT_DATE', get_option('build_date'))
+version_gen_environment.set('GIT_USER_AGENT', get_option('user_agent'))
+version_gen_environment.set('GIT_VERSION', get_option('version'))
+
 compiler = meson.get_compiler('c')
 
 libgit_sources = [
@@ -1485,6 +1495,7 @@ git_version_file = custom_target(
   ],
   input: meson.current_source_dir() / 'GIT-VERSION-FILE.in',
   output: 'GIT-VERSION-FILE',
+  env: version_gen_environment,
   build_always_stale: true,
 )
 
@@ -1501,6 +1512,7 @@ version_def_h = custom_target(
   # Depend on GIT-VERSION-FILE so that we don't always try to rebuild this
   # target for the same commit.
   depends: [git_version_file],
+  env: version_gen_environment,
 )
 
 # Build a separate library for "version.c" so that we do not have to rebuild
@@ -1544,6 +1556,7 @@ if host_machine.system() == 'windows'
     input: meson.current_source_dir() / 'git.rc.in',
     output: 'git.rc',
     depends: [git_version_file],
+    env: version_gen_environment,
   )
 
   common_main_sources += import('windows').compile_resources(git_rc,
diff --git a/meson_options.txt b/meson_options.txt
index 32a72139bae870745d9131cc9086a4594826be91..8ead1349550807420bdb95e55298ea4f3f2ea9d0 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -16,6 +16,16 @@ option('runtime_prefix', type: 'boolean', value: false,
 option('sane_tool_path', type: 'string', value: '',
   description: 'A colon-separated list of paths to prepend to PATH if your tools in /usr/bin are broken.')
 
+# Build information compiled into Git and other parts like documentation.
+option('build_date', type: 'string', value: '',
+  description: 'Build date reported by our documentation.')
+option('built_from_commit', type: 'string', value: '',
+  description: 'Commit that Git was built from reported by git-version(1).')
+option('user_agent', type: 'string', value: '',
+  description: 'User agent reported to remote servers.')
+option('version', type: 'string', value: '',
+  description: 'Version string reported by git-version(1) and other tools.')
+
 # Features supported by Git.
 option('curl', type: 'feature', value: 'enabled',
   description: 'Build helpers used to access remotes with the HTTP transport.')

-- 
2.48.0.rc0.184.g0fc57dec57.dirty