Merge "nix flake show: add the description if it exists" into main

5 files changed, 102 insertions, 9 deletions

diff --git a/doc/manual/change-authors.yml b/doc/manual/change-authors.yml
index 775149180..630af29ff 100644
--- a/doc/manual/change-authors.yml
+++ b/doc/manual/change-authors.yml
@@ -70,10 +70,17 @@ horrors:
 iFreilicht:
   github: iFreilicht
 
+isabelroses:
+  forgejo: isabelroses
+  github: isabelroses
+
 jade:
   forgejo: jade
   github: lf-
 
+kjeremy:
+  github: kjeremy
+
 kloenk:
   forgejo: kloenk
   github: kloenk
diff --git a/doc/manual/rl-next/nix-flake-show-description.md b/doc/manual/rl-next/nix-flake-show-description.md
new file mode 100644
index 000000000..e819a3a29
--- /dev/null
+++ b/doc/manual/rl-next/nix-flake-show-description.md
@@ -0,0 +1,37 @@
+---
+synopsis: "Lix will now show the package descriptions in when running `nix flake show`."
+cls: [1540]
+issues: []
+credits: [kjeremy, isabelroses]
+category: Improvements
+---
+
+When running `nix flake show`, Lix will now show the package descriptions, if they exist.
+
+Before:
+
+```shell
+$ nix flake show
+path:/home/isabel/dev/lix-show?lastModified=1721736108&narHash=sha256-Zo8HP1ur7Q2b39hKUEG8EAh/opgq8xJ2jvwQ/htwO4Q%3D
+└───packages
+    └───x86_64-linux
+        ├───aNoDescription: package 'simple'
+        ├───bOneLineDescription: package 'simple'
+        ├───cMultiLineDescription: package 'simple'
+        ├───dLongDescription: package 'simple'
+        └───eEmptyDescription: package 'simple'
+```
+
+After:
+
+```shell
+$ nix flake show
+path:/home/isabel/dev/lix-show?lastModified=1721736108&narHash=sha256-Zo8HP1ur7Q2b39hKUEG8EAh/opgq8xJ2jvwQ/htwO4Q%3D
+└───packages
+    └───x86_64-linux
+        ├───aNoDescription: package 'simple'
+        ├───bOneLineDescription: package 'simple' - 'one line'
+        ├───cMultiLineDescription: package 'simple' - 'line one'
+        ├───dLongDescription: package 'simple' - 'abcdefghijklmnopqrstuvwxyz'
+        └───eEmptyDescription: package 'simple'
+```
diff --git a/package.nix b/package.nix
index 1b711585d..62927e569 100644
--- a/package.nix
+++ b/package.nix
@@ -20,6 +20,7 @@
   doxygen,
   editline-lix ? __forDefaults.editline-lix,
   editline,
+  expect,
   git,
   gtest,
   jq,
@@ -254,6 +255,8 @@ stdenv.mkDerivation (finalAttrs: {
     ++ lib.optional (hostPlatform.canExecute buildPlatform) aws-sdk-cpp-nix
     ++ lib.optionals (finalAttrs.dontBuild) maybePropagatedInputs;
 
+  nativeCheckInputs = [ expect ];
+
   checkInputs = [
     gtest
     rapidcheck
diff --git a/src/nix/flake.cc b/src/nix/flake.cc
index 63b250d13..9d18b81b8 100644
--- a/src/nix/flake.cc
+++ b/src/nix/flake.cc
@@ -15,6 +15,7 @@
 #include "registry.hh"
 #include "eval-cache.hh"
 #include "markdown.hh"
+#include "terminal.hh"
 
 #include <nlohmann/json.hpp>
 #include <queue>
@@ -1225,25 +1226,42 @@ struct CmdFlakeShow : FlakeCommand, MixJSON
                 auto showDerivation = [&]()
                 {
                     auto name = visitor.getAttr(state->sName)->getString();
+                    std::optional<std::string> description;
+                    if (auto aMeta = visitor.maybeGetAttr(state->sMeta)) {
+                        if (auto aDescription = aMeta->maybeGetAttr(state->sDescription))
+                            description = aDescription->getString();
+                    }
+
                     if (json) {
-                        std::optional<std::string> description;
-                        if (auto aMeta = visitor.maybeGetAttr(state->sMeta)) {
-                            if (auto aDescription = aMeta->maybeGetAttr(state->sDescription))
-                                description = aDescription->getString();
-                        }
                         j.emplace("type", "derivation");
                         j.emplace("name", name);
                         if (description)
                             j.emplace("description", *description);
                     } else {
-                        logger->cout("%s: %s '%s'",
-                            headerPrefix,
+                        auto type =
                             attrPath.size() == 2 && attrPathS[0] == "devShell" ? "development environment" :
                             attrPath.size() >= 2 && attrPathS[0] == "devShells" ? "development environment" :
                             attrPath.size() == 3 && attrPathS[0] == "checks" ? "derivation" :
                             attrPath.size() >= 1 && attrPathS[0] == "hydraJobs" ? "derivation" :
-                            "package",
-                            name);
+                            "package";
+                        if (description && !description->empty()) {
+                            // Trim the string and only display the first line of the description.
+                            auto desc = nix::trim(*description);
+                            auto firstLineDesc = desc.substr(0, desc.find('\n'));
+
+                            std::string output = fmt("%s: %s '%s' - '%s'", headerPrefix, type, name, firstLineDesc);
+                            if (output.size() > getWindowSize().second) {
+                                // we resize to 4 less then the window size to account for the "...'" we append to
+                                // the final string, we also include the ' since that is removed when we truncate the string
+                                output.resize(getWindowSize().second - 4);
+                                output.append("...'");
+                            }
+
+                            logger->cout("%s", output.c_str());
+                        }
+                        else {
+                            logger->cout("%s: %s '%s'", headerPrefix, type, name);
+                        }
                     }
                 };
 
diff --git a/tests/functional/flakes/show.sh b/tests/functional/flakes/show.sh
index a3d300552..25f481575 100644
--- a/tests/functional/flakes/show.sh
+++ b/tests/functional/flakes/show.sh
@@ -85,3 +85,31 @@ assert show_output.legacyPackages.${builtins.currentSystem}.AAAAAASomeThingsFail
 assert show_output.legacyPackages.${builtins.currentSystem}.simple.name == "simple";
 true
 '
+
+cat >flake.nix<<EOF
+{
+  outputs = inputs: {
+    packages.$system = {
+      aNoDescription = import ./simple.nix;
+      bOneLineDescription = import ./simple.nix // { meta.description = "one line"; };
+      cMultiLineDescription = import ./simple.nix // { meta.description = ''
+         line one
+        line two
+      ''; };
+      dLongDescription = import ./simple.nix // { meta.description = ''
+        abcdefghijklmnopqrstuvwxyz
+      ''; };
+      eEmptyDescription = import ./simple.nix // { meta.description = ""; };
+    };
+  };
+}
+EOF
+unbuffer sh -c '
+  stty rows 20 cols 100
+  nix flake show > show-output.txt
+'
+test "$(awk -F '[:] ' '/aNoDescription/{print $NF}' ./show-output.txt)" = "package 'simple'"
+test "$(awk -F '[:] ' '/bOneLineDescription/{print $NF}' ./show-output.txt)" = "package 'simple' - 'one line'"
+test "$(awk -F '[:] ' '/cMultiLineDescription/{print $NF}' ./show-output.txt)" = "package 'simple' - 'line one'"
+test "$(awk -F '[:] ' '/dLongDescription/{print $NF}' ./show-output.txt)" = "package 'simple' - 'abcdefghijklmnopqrs...'"
+test "$(awk -F '[:] ' '/eEmptyDescription/{print $NF}' ./show-output.txt)" = "package 'simple'"