Progress percentage: only count actual work

When reporting the percentage already completed, only report actions
that were actually run. Cache hits are considered by reducing the
overall work to be considered, i.e., by making the completed actions
count more. In practice, however, most cache hits are discovered
ayway till the first progress status is reported.

1 files changed, 7 insertions, 1 deletions

diff --git a/src/buildtool/progress_reporting/base_progress_reporter.cpp b/src/buildtool/progress_reporting/base_progress_reporter.cpp
index 449f1dde..563a4a00 100644
--- a/src/buildtool/progress_reporting/base_progress_reporter.cpp
+++ b/src/buildtool/progress_reporting/base_progress_reporter.cpp
@@ -45,9 +45,15 @@ auto BaseProgressReporter::Reporter() -> GraphTraverser::progress_reporter_t {
                     }
                 }
                 constexpr int kOneHundred{100};
+                int total_work = total - cached;
+                int progress =
+                    kOneHundred;  // default if no work has to be done
+                if (total_work > 0) {
+                    progress = run * kOneHundred / total_work;
+                }
                 Logger::Log(LogLevel::Progress,
                             "[{:3}%] {} cached, {} run, {} processing{}.",
-                            (cached + run) * kOneHundred / total,
+                            progress,
                             cached,
                             run,
                             active,