Merge 5915951cbf into 806a91f7bf

src/libcmd/command.hh

@@ -352,6 +352,7 @@ void printClosureDiff(
     ref<Store> store,
     const StorePath & beforePath,
     const StorePath & afterPath,
+    bool json,
     std::string_view indent);
 
 }

src/nix/diff-closures.cc

@@ -4,6 +4,7 @@
 #include "common-args.hh"
 #include "names.hh"
 
+#include <nlohmann/json.hpp>
 #include <regex>
 
 #include "strings.hh"
@@ -15,9 +16,38 @@ struct Info
     std::string outputName;
 };
 
+struct DiffInfoForPackage
+{
+    int64_t sizeDelta;
+    std::string addedVersions;
+    std::string removedVersions;
+};
+
 // name -> version -> store paths
 typedef std::map<std::string, std::map<std::string, std::map<StorePath, Info>>> GroupedPaths;
 
+typedef std::map<std::string, DiffInfoForPackage> DiffInfo;
+
+
+nlohmann::json toJSON(DiffInfo diff)
+{
+    nlohmann::json res = nlohmann::json::object();
+
+    for (auto & [name, item] : diff) {
+        auto content = nlohmann::json::object();
+
+        if (!item.removedVersions.empty() || !item.addedVersions.empty()) {
+            content["versionsBefore"] = item.removedVersions;
+            content["versionsAfter"] = item.addedVersions;
+        }
+        content["sizeDelta"] = item.sizeDelta;
+
+        res[name] = std::move(content);
+    }
+
+    return res;
+}
+
 GroupedPaths getClosureInfo(ref<Store> store, const StorePath & toplevel)
 {
     StorePathSet closure;
@@ -47,20 +77,11 @@ GroupedPaths getClosureInfo(ref<Store> store, const StorePath & toplevel)
     return groupedPaths;
 }
 
-std::string showVersions(const std::set<std::string> & versions)
-{
-    if (versions.empty()) return "∅";
-    std::set<std::string> versions2;
-    for (auto & version : versions)
-        versions2.insert(version.empty() ? "ε" : version);
-    return concatStringsSep(", ", versions2);
-}
-
-void printClosureDiff(
+DiffInfo getDiffInfo(
     ref<Store> store,
     const StorePath & beforePath,
-    const StorePath & afterPath,
-    std::string_view indent)
+    const StorePath & afterPath
+)
 {
     auto beforeClosure = getClosureInfo(store, beforePath);
     auto afterClosure = getClosureInfo(store, afterPath);
@@ -69,6 +90,8 @@ void printClosureDiff(
     for (auto & [name, _] : beforeClosure) allNames.insert(name);
     for (auto & [name, _] : afterClosure) allNames.insert(name);
 
+    DiffInfo itemsToPrint;
+
     for (auto & name : allNames) {
         auto & beforeVersions = beforeClosure[name];
         auto & afterVersions = afterClosure[name];
@@ -85,7 +108,6 @@ void printClosureDiff(
         auto beforeSize = totalSize(beforeVersions);
         auto afterSize = totalSize(afterVersions);
         auto sizeDelta = (int64_t) afterSize - (int64_t) beforeSize;
-        auto showDelta = std::abs(sizeDelta) >= 8 * 1024;
 
         std::set<std::string> removed, unchanged;
         for (auto & [version, _] : beforeVersions)
@@ -95,22 +117,65 @@ void printClosureDiff(
         for (auto & [version, _] : afterVersions)
             if (!beforeVersions.count(version)) added.insert(version);
 
-        if (showDelta || !removed.empty() || !added.empty()) {
-            std::vector<std::string> items;
-            if (!removed.empty() || !added.empty())
-                items.push_back(fmt("%s → %s", showVersions(removed), showVersions(added)));
-            if (showDelta)
-                items.push_back(fmt("%s%+.1f KiB" ANSI_NORMAL, sizeDelta > 0 ? ANSI_RED : ANSI_GREEN, sizeDelta / 1024.0));
-            logger->cout("%s%s: %s", indent, name, concatStringsSep(", ", items));
+        if (!removed.empty() || !added.empty()) {
+            auto info = DiffInfoForPackage {
+                .sizeDelta = sizeDelta,
+                .addedVersions = showVersions(added),
+                .removedVersions = showVersions(removed)
+            };
+            itemsToPrint[name] = std::move(info);
         }
     }
+
+    return itemsToPrint;
+}
+
+std::string showVersions(const std::set<std::string> & versions)
+{
+    if (versions.empty()) return "∅";
+    std::set<std::string> versions2;
+    for (auto & version : versions)
+        versions2.insert(version.empty() ? "ε" : version);
+    return concatStringsSep(", ", versions2);
+}
+
+void renderDiffInfo(
+    DiffInfo diff,
+    const std::string_view indent)
+{
+    for (auto & [name, item] : diff) {
+        auto showDelta = std::abs(item.sizeDelta) >= 8 * 1024;
+
+        std::vector<std::string> line;
+        if (!item.removedVersions.empty() || !item.addedVersions.empty())
+            line.push_back(fmt("%s → %s", item.removedVersions, item.addedVersions));
+        if (showDelta)
+            line.push_back(fmt("%s%+.1f KiB" ANSI_NORMAL, item.sizeDelta > 0 ? ANSI_RED : ANSI_GREEN, item.sizeDelta / 1024.0));
+        logger->cout("%s%s: %s", indent, name, concatStringsSep(", ", line));
+    }
+}
+
+void printClosureDiff(
+    ref<Store> store,
+    const StorePath & beforePath,
+    const StorePath & afterPath,
+    const bool json,
+    const std::string_view indent)
+{
+    DiffInfo diff = getDiffInfo(store, beforePath, afterPath);
+
+    if (json) {
+        logger->cout(toJSON(diff).dump());
+    } else {
+        renderDiffInfo(diff, indent);
+    }
 }
 
 }
 
 using namespace nix;
 
-struct CmdDiffClosures : SourceExprCommand, MixOperateOnOptions
+struct CmdDiffClosures : SourceExprCommand, MixJSON, MixOperateOnOptions
 {
     std::string _before, _after;
 
@@ -138,7 +203,7 @@ struct CmdDiffClosures : SourceExprCommand, MixOperateOnOptions
         auto beforePath = Installable::toStorePath(getEvalStore(), store, Realise::Outputs, operateOn, before);
         auto after = parseInstallable(store, _after);
         auto afterPath = Installable::toStorePath(getEvalStore(), store, Realise::Outputs, operateOn, after);
-        printClosureDiff(store, beforePath, afterPath, "");
+        printClosureDiff(store, beforePath, afterPath, json, "");
     }
 };
 

src/nix/diff-closures.md

@@ -24,28 +24,50 @@ of packages, as well as changes in store path sizes.
 
 For each package name in the two closures (where a package name is
 defined as the name component of a store path excluding the version),
-if there is a change in the set of versions of the package, or a
-change in the size of the store paths of more than 8 KiB, it prints a
-line like this:
+it returns information about the change in the set of versions of the
+package, and the change in the size of the store paths.
 
-```console
-dolphin: 20.08.1 → 20.08.2, +13.9 KiB
-```
-
-No size change is shown if it's below the threshold. If the package
-does not exist in either the *before* or *after* closures, it is
-represented using `∅` (empty set) on the appropriate side of the
-arrow. If a package has an empty version string, the version is
-rendered as `ε` (epsilon).
+If the package does not exist in either the *before* or *after*
+closures, it is represented using `∅` (empty set) on the appropriate
+side of the arrow. If a package has an empty version string, the
+version is rendered as `ε` (epsilon).
 
 There may be multiple versions of a package in each closure. In that
 case, only the changed versions are shown. Thus,
 
 ```console
-libfoo: 1.2, 1.3 → 1.4
+1.2, 1.3 → 1.4
 ```
 
 leaves open the possibility that there are other versions (e.g. `1.1`)
 that exist in both closures.
 
+## Regular output
+
+The regular output prints lines like this:
+
+```console
+dolphin: 20.08.1 → 20.08.2, +13.9 KiB
+```
+
+No size change is shown if it's below the 8 KiB threshold.
+
+## JSON output
+
+With `--json`, the output is in a JSON representation suitable for automatic
+processing by other tools.
+
+The printed result looks like this:
+
+```json
+{
+  "dolphin": {
+    "after": "20.08.1",
+    "before": "20.08.2",
+    "sizeDelta": 13900
+  },
+  ...
+}
+```
+
 )""

src/nix/profile.cc

@@ -850,6 +850,7 @@ struct CmdProfileDiffClosures : virtual StoreCommand, MixDefaultProfile
                 printClosureDiff(store,
                     store->followLinksToStorePath(prevGen->path),
                     store->followLinksToStorePath(gen.path),
+                    false,
                     "  ");
             }