correctly handle add flag constraints

License: MIT
Signed-off-by: Steven Allen <steven@stebalien.com>

core/commands/add.go

@@ -114,11 +114,11 @@ You can now check what blocks have been created by:
 		cmdkit.BoolOption(hiddenOptionName, "H", "Include files that are hidden. Only takes effect on recursive add."),
 		cmdkit.StringOption(chunkerOptionName, "s", "Chunking algorithm, size-[bytes] or rabin-[min]-[avg]-[max]").WithDefault("size-262144"),
 		cmdkit.BoolOption(pinOptionName, "Pin this object when adding.").WithDefault(true),
-		cmdkit.BoolOption(rawLeavesOptionName, "Use raw blocks for leaf nodes. (experimental)"),
-		cmdkit.BoolOption(noCopyOptionName, "Add the file using filestore. (experimental)"),
+		cmdkit.BoolOption(rawLeavesOptionName, "Use raw blocks for leaf nodes. Implies CIDv1, defaults to on if CIDv1 is enabled. (experimental)"),
+		cmdkit.BoolOption(noCopyOptionName, "Add the file using filestore. Implies raw-leaves. (experimental)"),
 		cmdkit.BoolOption(fstoreCacheOptionName, "Check the filestore for pre-existing blocks. (experimental)"),
-		cmdkit.IntOption(cidVersionOptionName, "Cid version. Non-zero value will change default of 'raw-leaves' to true. (experimental)").WithDefault(0),
-		cmdkit.StringOption(hashOptionName, "Hash function to use. Will set Cid version to 1 if used. (experimental)").WithDefault("sha2-256"),
+		cmdkit.IntOption(cidVersionOptionName, "CID version. Defaults to 0 unless an option that depends on CIDv1 is passed. (experimental)"),
+		cmdkit.StringOption(hashOptionName, "Hash function to use. Implies CIDv1 if not sha2-256. (experimental)").WithDefault("sha2-256"),
 	},
 	PreRun: func(req *cmds.Request, env cmds.Environment) error {
 		quiet, _ := req.Options[quietOptionName].(bool)
@@ -170,31 +170,70 @@ You can now check what blocks have been created by:
 		rawblks, rbset := req.Options[rawLeavesOptionName].(bool)
 		nocopy, _ := req.Options[noCopyOptionName].(bool)
 		fscache, _ := req.Options[fstoreCacheOptionName].(bool)
-		cidVer, _ := req.Options[cidVersionOptionName].(int)
-		hashFunStr, hfset := req.Options[hashOptionName].(string)
-
+		cidVer, cidVerSet := req.Options[cidVersionOptionName].(int)
+		hashFunStr, _ := req.Options[hashOptionName].(string)
+
+		// Given the following constraints:
+		//
+		// nocopy -> filestoreEnabled
+		// nocopy -> rawblocks
+		// rawblocks -> cidv1
+		// (hash != sha2-256) -> cidv1
+		//
+		// We solve for the values of rawblocks and cidv1 in the
+		// following order of preference:
+		//
+		// 1. If cidv1 isn't fixed, set it to false and try solving.
+		// 2. If rawblocks isn't fixed, set it to true and try solving.
+		//
+		// If neither solution works, give up (we have a conflict).
+
+		// nocopy -> filestorEnabled
 		if nocopy && !cfg.Experimental.FilestoreEnabled {
 			res.SetError(errors.New("filestore is not enabled, see https://git.io/vy4XN"),
 				cmdkit.ErrClient)
 			return
 		}
 
-		if hfset && hashFunStr != "sha2-256" && cidVer == 0 {
-			cidVer = 1
-		}
-
-		if cidVer > 0 && !rbset {
+		// nocopy -> rawblocks
+		if nocopy && !rawblks {
+			// fixed?
+			if rbset {
+				res.SetError(
+					fmt.Errorf("nocopy option requires '--raw-leaves' to be enabled as well"),
+					cmdkit.ErrNormal,
+				)
+				return
+			}
+			// No, satisfy mandatory constraint.
 			rawblks = true
 		}
 
-		// if rawblocks is not explicitly set but nocopy is, set rawblocks
-		if nocopy && !rbset {
-			rawblks = true
+		if !cidVerSet {
+			// Default to CIDv0 if possible.
+			// Conditions: no raw blocks, sha2-256
+			if hashFunStr == "sha2-256" && !rawblks {
+				cidVer = 0
+			} else {
+				cidVer = 1
+			}
+		} else if cidVer == 0 {
+			// CIDv0 *was* set...
+			if hashFunStr != "sha2-256" {
+				res.SetError(errors.New("CIDv0 only supports sha2-256"), cmdkit.ErrClient)
+				return
+			} else if rawblks {
+				res.SetError(
+					errors.New("CIDv0 incompatible with raw-leaves and/or nocopy"),
+					cmdkit.ErrClient,
+				)
+				return
+			}
 		}
 
-		if nocopy && !rawblks {
-			res.SetError(fmt.Errorf("nocopy option requires '--raw-leaves' to be enabled as well"), cmdkit.ErrNormal)
-			return
+		// cidV1 -> raw blocks (by default)
+		if cidVer > 0 && !rbset {
+			rawblks = true
 		}
 
 		prefix, err := dag.PrefixForCidVersion(cidVer)