Don't crash when copying realisations to a non-ca remote

thufschmitt · thufschmitt · commit e1c0bf9a3534 · 2021-02-19T17:58:28.000+01:00
Rather throw a proper exception, and catch&amp;log it on the client side
diff --git a/src/libstore/globals.cc b/src/libstore/globals.cc
@@ -159,10 +159,15 @@ bool Settings::isExperimentalFeatureEnabled(const std::string & name)
     return std::find(f.begin(), f.end(), name) != f.end();
 }
 
+MissingExperimentalFeature::MissingExperimentalFeature(std::string feature)
+    : Error("experimental Nix feature '%1%' is disabled; use '--experimental-features %1%' to override", feature)
+    , missingFeature(feature)
+    {}
+
 void Settings::requireExperimentalFeature(const std::string & name)
 {
     if (!isExperimentalFeatureEnabled(name))
-        throw Error("experimental Nix feature '%1%' is disabled; use '--experimental-features %1%' to override", name);
+        throw MissingExperimentalFeature(name);
 }
 
 bool Settings::isWSL1()
diff --git a/src/libstore/globals.hh b/src/libstore/globals.hh
@@ -28,6 +28,16 @@ struct MaxBuildJobsSetting : public BaseSetting<unsigned int>
     void set(const std::string & str, bool append = false) override;
 };
 
+/* MakeError(MissingExperimentalFeature, Error); */
+class MissingExperimentalFeature: public Error
+{
+public:
+    std::string missingFeature;
+
+    MissingExperimentalFeature(std::string feature);
+    virtual const char* sname() const override { return "MissingExperimentalFeature"; }
+};
+
 class Settings : public Config {
 
     unsigned int getDefaultCores();
@@ -615,7 +625,7 @@ public:
           is `root`.
 
           > **Warning**
-          > 
+          >
           > Adding a user to `trusted-users` is essentially equivalent to
           > giving that user root access to the system. For example, the user
           > can set `sandbox-paths` and thereby obtain read access to
@@ -672,7 +682,7 @@ public:
           send a series of commands to modify various settings to stdout. The
           currently recognized commands are:
 
-            - `extra-sandbox-paths`  
+            - `extra-sandbox-paths`
               Pass a list of files and directories to be included in the
               sandbox for this build. One entry per line, terminated by an
               empty line. Entries have the same format as `sandbox-paths`.
@@ -705,13 +715,13 @@ public:
           The program executes with no arguments. The program's environment
           contains the following environment variables:
 
-            - `DRV_PATH`  
+            - `DRV_PATH`
               The derivation for the built paths.
 
               Example:
               `/nix/store/5nihn1a7pa8b25l9zafqaqibznlvvp3f-bash-4.4-p23.drv`
 
-            - `OUT_PATHS`  
+            - `OUT_PATHS`
               Output paths of the built derivation, separated by a space
               character.
 
@@ -742,7 +752,7 @@ public:
           documentation](https://ec.haxx.se/usingcurl-netrc.html).
 
           > **Note**
-          > 
+          >
           > This must be an absolute path, and `~` is not resolved. For
           > example, `~/.netrc` won't resolve to your home directory's
           > `.netrc`.
diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc
@@ -655,6 +655,7 @@ void LocalStore::checkDerivationOutputs(const StorePath & drvPath, const Derivat
 
 void LocalStore::registerDrvOutput(const Realisation & info)
 {
+    settings.requireExperimentalFeature("ca-derivations");
     auto state(_state.lock());
     retrySQLite<void>([&]() {
         state->stmts->RegisterRealisedOutput.use()
diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
@@ -794,8 +794,18 @@ std::map<StorePath, StorePath> copyPaths(ref<Store> srcStore, ref<Store> dstStor
             realisations.insert(*realisation);
     }
     auto pathsMap = copyPaths(srcStore, dstStore, storePaths, repair, checkSigs, substitute);
-    for (auto& realisation : realisations) {
-        dstStore->registerDrvOutput(realisation);
+    try {
+        for (auto& realisation : realisations) {
+            dstStore->registerDrvOutput(realisation);
+        }
+    } catch (MissingExperimentalFeature & e) {
+        // Don't fail if the remote doesn't support CA derivations is it might
+        // not be whithin our control to change that, and we might still want
+        // to at least copy the output paths.
+        if (e.missingFeature == "ca-derivations")
+            ignoreException();
+        else
+            throw;
     }
 
     return pathsMap;

Original file line number	Diff line number	Diff line change
`@@ -159,10 +159,15 @@ bool Settings::isExperimentalFeatureEnabled(const std::string & name)`
`159`	`159`	`return std::find(f.begin(), f.end(), name) != f.end();`
`160`	`160`	`}`
`161`	`161`
	`162`	`+MissingExperimentalFeature::MissingExperimentalFeature(std::string feature)`
	`163`	`+ : Error("experimental Nix feature '%1%' is disabled; use '--experimental-features %1%' to override", feature)`
	`164`	`+ , missingFeature(feature)`
	`165`	`+ {}`
	`166`	`+`
`162`	`167`	`void Settings::requireExperimentalFeature(const std::string & name)`
`163`	`168`	`{`
`164`	`169`	`if (!isExperimentalFeatureEnabled(name))`
`165`		`- throw Error("experimental Nix feature '%1%' is disabled; use '--experimental-features %1%' to override", name);`
	`170`	`+ throw MissingExperimentalFeature(name);`
`166`	`171`	`}`
`167`	`172`
`168`	`173`	`bool Settings::isWSL1()`
Original file line number	Diff line number	Diff line change
`@@ -655,6 +655,7 @@ void LocalStore::checkDerivationOutputs(const StorePath & drvPath, const Derivat`
`655`	`655`
`656`	`656`	`void LocalStore::registerDrvOutput(const Realisation & info)`
`657`	`657`	`{`
	`658`	`+ settings.requireExperimentalFeature("ca-derivations");`
`658`	`659`	`auto state(_state.lock());`
`659`	`660`	`retrySQLite<void>([&]() {`
`660`	`661`	`state->stmts->RegisterRealisedOutput.use()`