C#: Re-implement the git version logic using an attribute.

csharp/scripts/BUILD.bazel

@@ -0,0 +1,17 @@
+py_binary(
+    name = "gen-assembly-info",
+    srcs = ["gen-assembly-info.py"],
+    deps = ["@rules_python//python/runfiles"],
+)
+
+# this is an instance of the dbscheme kept in the bazel build tree
+# this allows everything that bazel builds to be up-to-date,
+# independently from whether //go:gen was already run to update the checked in files
+genrule(
+    name = "assembly-info-src",
+    srcs = ["@semmle_code//:git_info"],
+    outs = ["AssemblyInfo.cs"],
+    cmd = "$(execpath :gen-assembly-info) $@ $(SRCS)",
+    tools = [":gen-assembly-info"],
+    visibility = ["//csharp:__subpackages__"],
+)

csharp/scripts/gen-assembly-info.py

@@ -0,0 +1,34 @@
+"""
+Generates an `AssemblyInfo.cs` file that specifies the `AssemblyInformationalVersion` attribute.
+
+This attribute is set to the git version string of the repository."""
+
+import pathlib
+import argparse
+
+
+def options():
+    p = argparse.ArgumentParser(
+        description="Generate the assembly info file that contains the git SHA and branch name"
+    )
+    p.add_argument("output", help="The path to the output file")
+    p.add_argument("gitinfo_files", nargs="+", help="The path to the gitinfo files")
+    return p.parse_args()
+
+
+opts = options()
+
+gitfiles = dict()
+for file in map(pathlib.Path, opts.gitinfo_files):
+    gitfiles[file.name] = file
+
+version_string = gitfiles["git-ql-describe-all.log"].read_text().strip()
+version_string += f" ({gitfiles['git-ql-rev-parse.log'].read_text().strip()})"
+
+output_file = pathlib.Path(opts.output)
+output_file_contents = f"""
+using System.Reflection;
+
+[assembly: AssemblyInformationalVersion("{version_string}")]
+"""
+output_file.write_text(output_file_contents)