Add skip when no output enabled, even if feature is enabled (#209)

vergen/src/emitter.rs

@@ -988,4 +988,27 @@ pub(crate) mod test {
         teardown();
         Ok(())
     }
+
+    #[cfg(all(
+        feature = "build",
+        feature = "rustc",
+        all(
+            feature = "git",
+            any(feature = "gitcl", feature = "git2", feature = "gix")
+        ),
+        feature = "cargo",
+        feature = "si"
+    ))]
+    #[test]
+    #[serial_test::serial]
+    fn all_features_no_output() -> Result<()> {
+        use crate::utils::testutils::{setup, teardown};
+
+        setup();
+        let mut stdout_buf = vec![];
+        _ = EmitBuilder::builder().emit_to(&mut stdout_buf)?;
+        assert!(stdout_buf.is_empty());
+        teardown();
+        Ok(())
+    }
 }

vergen/src/feature/build.rs

@@ -17,6 +17,12 @@ pub(crate) struct Config {
     pub(crate) build_timestamp: bool,
 }
 
+impl Config {
+    pub(crate) fn any(self) -> bool {
+        self.build_date || self.build_timestamp
+    }
+}
+
 /// The `VERGEN_BUILD_*` configuration features
 ///
 /// | Variable | Sample |
@@ -175,7 +181,9 @@ impl EmitBuilder {
         map: &mut RustcEnvMap,
         warnings: &mut Vec<String>,
     ) -> Result<()> {
-        self.add_timestamp_entries(idempotent, map, warnings)?;
+        if self.build_config.any() {
+            self.add_timestamp_entries(idempotent, map, warnings)?;
+        }
         Ok(())
     }
 

vergen/src/feature/cargo.rs

@@ -24,6 +24,12 @@ pub(crate) struct Config {
     pub(crate) cargo_target_triple: bool,
 }
 
+impl Config {
+    pub(crate) fn any(self) -> bool {
+        self.cargo_debug || self.cargo_features || self.cargo_opt_level || self.cargo_target_triple
+    }
+}
+
 /// Copnfigure the emission of `VERGEN_CARGO_*` instructions
 ///
 /// **NOTE** - All cargo instructions are considered deterministic.  If you change
@@ -176,40 +182,41 @@ impl EmitBuilder {
     }
 
     pub(crate) fn add_cargo_map_entries(&self, map: &mut RustcEnvMap) -> Result<()> {
-        if self.cargo_config.cargo_debug {
-            if let Ok(value) = env::var(CARGO_DEBUG) {
-                add_map_entry(VergenKey::CargoDebug, value, map);
-            } else {
-                add_map_entry(VergenKey::CargoDebug, env::var("DEBUG")?, map);
+        if self.cargo_config.any() {
+            if self.cargo_config.cargo_debug {
+                if let Ok(value) = env::var(CARGO_DEBUG) {
+                    add_map_entry(VergenKey::CargoDebug, value, map);
+                } else {
+                    add_map_entry(VergenKey::CargoDebug, env::var("DEBUG")?, map);
+                }
             }
-        }
 
-        if self.cargo_config.cargo_features {
-            if let Ok(value) = env::var(CARGO_FEATURES) {
-                add_map_entry(VergenKey::CargoFeatures, value, map);
-            } else {
-                let features: Vec<String> = env::vars().filter_map(is_cargo_feature).collect();
-                let feature_str = features.as_slice().join(",");
-                add_map_entry(VergenKey::CargoFeatures, feature_str, map);
+            if self.cargo_config.cargo_features {
+                if let Ok(value) = env::var(CARGO_FEATURES) {
+                    add_map_entry(VergenKey::CargoFeatures, value, map);
+                } else {
+                    let features: Vec<String> = env::vars().filter_map(is_cargo_feature).collect();
+                    let feature_str = features.as_slice().join(",");
+                    add_map_entry(VergenKey::CargoFeatures, feature_str, map);
+                }
             }
-        }
 
-        if self.cargo_config.cargo_opt_level {
-            if let Ok(value) = env::var(CARGO_OPT_LEVEL) {
-                add_map_entry(VergenKey::CargoOptLevel, value, map);
-            } else {
-                add_map_entry(VergenKey::CargoOptLevel, env::var("OPT_LEVEL")?, map);
+            if self.cargo_config.cargo_opt_level {
+                if let Ok(value) = env::var(CARGO_OPT_LEVEL) {
+                    add_map_entry(VergenKey::CargoOptLevel, value, map);
+                } else {
+                    add_map_entry(VergenKey::CargoOptLevel, env::var("OPT_LEVEL")?, map);
+                }
             }
-        }
 
-        if self.cargo_config.cargo_target_triple {
-            if let Ok(value) = env::var(CARGO_TARGET_TRIPLE) {
-                add_map_entry(VergenKey::CargoTargetTriple, value, map);
-            } else {
-                add_map_entry(VergenKey::CargoTargetTriple, env::var("TARGET")?, map);
+            if self.cargo_config.cargo_target_triple {
+                if let Ok(value) = env::var(CARGO_TARGET_TRIPLE) {
+                    add_map_entry(VergenKey::CargoTargetTriple, value, map);
+                } else {
+                    add_map_entry(VergenKey::CargoTargetTriple, env::var("TARGET")?, map);
+                }
             }
         }
-
         Ok(())
     }
 }

vergen/src/feature/git/cmd.rs

@@ -497,13 +497,16 @@ impl EmitBuilder {
         warnings: &mut Vec<String>,
         rerun_if_changed: &mut Vec<String>,
     ) -> Result<()> {
-        let git_cmd = if let Some(cmd) = self.git_config.git_cmd {
-            cmd
-        } else {
-            "git --version"
-        };
-        check_git(git_cmd).and_then(check_inside_git_worktree)?;
-        self.inner_add_git_map_entries(path, idempotent, map, warnings, rerun_if_changed)
+        if self.any() {
+            let git_cmd = if let Some(cmd) = self.git_config.git_cmd {
+                cmd
+            } else {
+                "git --version"
+            };
+            check_git(git_cmd).and_then(check_inside_git_worktree)?;
+            self.inner_add_git_map_entries(path, idempotent, map, warnings, rerun_if_changed)?;
+        }
+        Ok(())
     }
 
     #[allow(clippy::needless_pass_by_value)]

vergen/src/feature/git/git2.rs

@@ -300,7 +300,10 @@ impl EmitBuilder {
         warnings: &mut Vec<String>,
         rerun_if_changed: &mut Vec<String>,
     ) -> Result<()> {
-        self.inner_add_git_map_entries(path, idempotent, map, warnings, rerun_if_changed)
+        if self.any() {
+            self.inner_add_git_map_entries(path, idempotent, map, warnings, rerun_if_changed)?;
+        }
+        Ok(())
     }
 
     #[cfg(test)]
@@ -312,11 +315,13 @@ impl EmitBuilder {
         warnings: &mut Vec<String>,
         rerun_if_changed: &mut Vec<String>,
     ) -> Result<()> {
-        if self.git_config.fail {
-            Err(anyhow!("failed to create entries"))
-        } else {
-            self.inner_add_git_map_entries(path, idempotent, map, warnings, rerun_if_changed)
+        if self.any() {
+            if self.git_config.fail {
+                return Err(anyhow!("failed to create entries"));
+            }
+            self.inner_add_git_map_entries(path, idempotent, map, warnings, rerun_if_changed)?;
         }
+        Ok(())
     }
 
     fn inner_add_git_map_entries(

vergen/src/feature/git/gix.rs

@@ -298,7 +298,10 @@ impl EmitBuilder {
         warnings: &mut Vec<String>,
         rerun_if_changed: &mut Vec<String>,
     ) -> Result<()> {
-        self.inner_add_git_map_entries(path, idempotent, map, warnings, rerun_if_changed)
+        if self.any() {
+            self.inner_add_git_map_entries(path, idempotent, map, warnings, rerun_if_changed)?;
+        }
+        Ok(())
     }
 
     #[cfg(test)]
@@ -310,11 +313,13 @@ impl EmitBuilder {
         warnings: &mut Vec<String>,
         rerun_if_changed: &mut Vec<String>,
     ) -> Result<()> {
-        if self.git_config.fail {
-            Err(anyhow!("failed to create entries"))
-        } else {
-            self.inner_add_git_map_entries(path, idempotent, map, warnings, rerun_if_changed)
+        if self.any() {
+            if self.git_config.fail {
+                return Err(anyhow!("failed to create entries"));
+            }
+            self.inner_add_git_map_entries(path, idempotent, map, warnings, rerun_if_changed)?;
         }
+        Ok(())
     }
 
     #[allow(clippy::unnecessary_wraps)]

vergen/src/feature/rustc.rs

@@ -24,6 +24,17 @@ pub(crate) struct Config {
     rustc_str_to_test: Option<&'static str>,
 }
 
+impl Config {
+    pub(crate) fn any(self) -> bool {
+        self.rustc_channel
+            || self.rustc_commit_date
+            || self.rustc_commit_hash
+            || self.rustc_host_triple
+            || self.rustc_llvm_version
+            || self.rustc_semver
+    }
+}
+
 /// The `VERGEN_RUSTC_*` configuration features
 ///
 /// **NOTE** - All rustc instructions are considered deterministic.  If you change
@@ -169,7 +180,10 @@ impl EmitBuilder {
         map: &mut RustcEnvMap,
         warnings: &mut Vec<String>,
     ) -> Result<()> {
-        self.add_rustc_to_map(version_meta(), map, warnings)
+        if self.rustc_config.any() {
+            self.add_rustc_to_map(version_meta(), map, warnings)?;
+        }
+        Ok(())
     }
 
     #[cfg(test)]
@@ -185,7 +199,10 @@ impl EmitBuilder {
         } else {
             version_meta()
         };
-        self.add_rustc_to_map(vm, map, warnings)
+        if self.rustc_config.any() {
+            self.add_rustc_to_map(vm, map, warnings)?;
+        }
+        Ok(())
     }
 
     fn add_rustc_to_map(

vergen/src/feature/si.rs

@@ -37,6 +37,20 @@ pub(crate) struct Config {
     fail_pid: bool,
 }
 
+impl Config {
+    pub(crate) fn any(&self) -> bool {
+        self.si_name
+            || self.si_os_version
+            || self.si_user
+            || self.si_memory
+            || self.si_cpu_vendor
+            || self.si_cpu_core_count
+            || self.si_cpu_name
+            || self.si_cpu_brand
+            || self.si_cpu_frequency
+    }
+}
+
 /// The `VERGEN_SYSINFO_*` configuration features
 ///
 /// | Variable | Sample |
@@ -213,17 +227,19 @@ impl EmitBuilder {
         map: &mut RustcEnvMap,
         warnings: &mut Vec<String>,
     ) {
-        let system = setup_system();
-
-        self.add_sysinfo_name(&system, idempotent, map, warnings);
-        self.add_sysinfo_os_verison(&system, idempotent, map, warnings);
-        self.add_sysinfo_user(&system, idempotent, map, warnings);
-        self.add_sysinfo_total_memory(&system, idempotent, map, warnings);
-        self.add_sysinfo_cpu_vendor(&system, idempotent, map, warnings);
-        self.add_sysinfo_cpu_core_count(&system, idempotent, map, warnings);
-        self.add_sysinfo_cpu_name(&system, idempotent, map, warnings);
-        self.add_sysinfo_cpu_brand(&system, idempotent, map, warnings);
-        self.add_sysinfo_cpu_frequency(&system, idempotent, map, warnings);
+        if self.sysinfo_config.any() {
+            let system = setup_system();
+
+            self.add_sysinfo_name(&system, idempotent, map, warnings);
+            self.add_sysinfo_os_verison(&system, idempotent, map, warnings);
+            self.add_sysinfo_user(&system, idempotent, map, warnings);
+            self.add_sysinfo_total_memory(&system, idempotent, map, warnings);
+            self.add_sysinfo_cpu_vendor(&system, idempotent, map, warnings);
+            self.add_sysinfo_cpu_core_count(&system, idempotent, map, warnings);
+            self.add_sysinfo_cpu_name(&system, idempotent, map, warnings);
+            self.add_sysinfo_cpu_brand(&system, idempotent, map, warnings);
+            self.add_sysinfo_cpu_frequency(&system, idempotent, map, warnings);
+        }
     }
 
     fn add_sysinfo_name(